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The Effects of Nonfiber Carbohydrate Source and Protein Degradability on Lactation Performance of Holstein Cows


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THE EFFECTS OF NONFIBER CARBOHYDRATE SOURCE AND PROTEIN DEGRADABILITY ON LACTATION PERFORMANCE OF HOLSTEIN COWS By COLLEEN CASEY LARSON A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2003

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Copyright 2003 by Colleen Casey Larson

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This thesis is dedicated to God who provided me the strength and perseverance to complete my graduate program. It is also dedicated to my family who provided unconditional support and understanding throughout the attainment of this goal. I would like to thank my mom, Connie Casey, for the help, encouragement and support she always demonstrated. I would like to thank my dad, Mike Casey, for always supporting me in any goal that I wanted to attain. Finally, I want to thank my husband, Travis Larson, for the support and encouragement throughout this time in our lives.

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ACKNOWLEDGMENTS I wish to express my gratitude to all of the people who contributed and supported me throughout my Master of Science program. First, I wish to express my appreciation to the Milk Check Off program that provided funding for this study. Next, I would like to thank the supervisor of my committee, Dr. Mary Beth Hall, for her patience, guidance, and diligence in helping me attain this goal. Also, I want to thank the members of my committee, Dr. Charles Staples, Dr. Adegbola Adesogan, and the late Dr. Bill Kunkle, for always being willing to take time to answer questions and provide encouragement. Next I would like to recognize all of the people who helped with the study at the farm or in the laboratory: Lucia Holtshausen, Heidi Bissell, Celeste Kearney, Jocelyn Croci, Alexandra Amorocho, Najesda Amorocho, Ashley Hughes, and Connie Casey. I am indebted to each of them for their diligent efforts. I also own a great deal of thanks to the Dairy Research Unit (Hague, FL), with special thanks to Carrie Bradley and those who fed the cows each day. Again, I wish to express my appreciation to all those who made this research possible. iv

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TABLE OF CONTENTS page ACKNOWLEDGMENTS.................................................................................................iv LIST OF TABLES............................................................................................................vii LIST OF FIGURES.........................................................................................................viii ABBREVIATIONS...........................................................................................................ix ABSTRACT.........................................................................................................................x CHAPTER 1 INTRODUCTION........................................................................................................1 2 REVIEW OF THE LITERATURE ON NONFIBER CARBOHYDRATE SOURCE AND RUMEN UNDEGRADABLE PROTEIN IN RUMINANT DIETS..................5 Nonfiber Carbohydrates................................................................................................5 Partitioning............................................................................................................5 Starch.....................................................................................................................6 Sugars....................................................................................................................8 Pectic Substances and Pectin...............................................................................14 Effects of Starch, Sugars, and Pectin on Animal Response.......................................18 Effects of RUP and NFC Source in Ruminant Diets..................................................28 3 EFFECTS OF NONFIBER CARBOHYDRATE SOURCE AND PROTEIN DEGRADABILITY ON LACTATION PEFORMANCE OF HOLSTEIN COWS.........................................................................................................................42 Introduction.................................................................................................................42 Materials and Methods...............................................................................................43 Cows, Diets, and Facilities..................................................................................43 Sample Collection and Analysis..........................................................................44 In Situ Ruminal Incubations................................................................................47 Ruminal Fluid Sampling and Analysis................................................................48 Statistical Analysis..............................................................................................49 Results and Discussion...............................................................................................50 Intake and Lactation Performance.......................................................................50 v

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Plasma and Ruminal Measures............................................................................54 Conclusions.................................................................................................................57 APPENDIX A MILK PRODUCTION, COMPOSITION, AND PLASMA MEASURES................65 B RUMINAL PH AND VOLATILE FATTY ACIDS..................................................71 C IN SITU DEGRADATION OF SORGHUM SILAGE..............................................81 D NUTRIENT INTAKES..............................................................................................87 LIST OF REFERENCES.................................................................................................101 BIOGRAPHICAL SKETCH...........................................................................................108 vi

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LIST OF TABLES Table page 2-1 The effects of NFC source and/or RDP/RUP supplementation on ruminal characteristics...........................................................................................................35 2-2 The effects of NFC source and/or RUP/RDP supplementation on intake, plasma measures, and milk production and composition.....................................................39 3-1 Ingredient and chemical composition of diets..........................................................59 3-2 Nutrient intake by dietary treatment.........................................................................61 3-3 Milk production, milk composition, blood measures, and efficiency measures by dietary treatment.......................................................................................................62 3-4 Ruminal fluid measures by dietary treatment..........................................................63 3-5 Residual NDF by hour of in situ incubation and dietary treatment.........................64 A-1 Averages for milk production, fat percent, protein percent, milk urea N (MUN), and somatic cell count (SCC) by cow period, and diet..........................................65 A-2 Averages for plasma urea nitrogen (PUN), glucose, and insulin by cow, period, and diet. ..................................................................................................................67 B-1 Volatile fatty acids (VFA) and rumen pH by cow, period, hour of sampling, and diet............................................................................................................................72 C-1 In situ degradation of sorghum silage by cow, period, diet, and hour of sampling...................................................................................................................81 D-1 Offered feed and nutrients by cow, period and diet.................................................88 D-2 Refused feed and nutrients by cow, period and diet................................................93 D-3 Intake of feed and nutrients by cow, period and diet...............................................97 vii

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LIST OF FIGURES Figure page 3-1 Temporal patterns of ruminal pH by dietary treatment. Cows were fed following the 0 sampling hour..................................................................................................60 3-2 Acetate, propionate, butyrate and BCVFA by sampling hour for ST-RUP ST+RUP SF-RUP SF+RUP and SU-RUP and SU+RUP ............60 viii

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ABBREVIATIONS ADF acid detergent fiber BCVFA branch chain VFA BW body weight CF crude fiber CP crude protein CPD citrus pulp diet CSC cracked, shelled corn diet DIM days in milk DM dry matter DMI dry matter intake ESBM expeller soybean meal FCM fat-corrected milk FPCM fatand protein-corrected milk HCP corn and dried citrus pulp diet HD hominy diet HMEC high moisture ear corn diet MUN milk urea nitrogen NDF neutral detergent fiber NDFCP neutral detergent fiber crude protein NDSC neutral detergent-soluble carbohydrate NDSF neutral detergent-soluble fiber NEL net energy of lactation NFC nonfiber carbohydrate NFE nitrogen-free extract NSC nonstructural carbohydrate NRC National Research Council OA organic acid OM organic matter PUN plasma urea nitrogen RDP rumen degradable protein RUP rumen undegradable protein SCC somatic cell count SF soluble fiber, citrus pulp SM sugar + malate SSBM solvent soybean meal ST starch, ground corn SU sugar, molasses+sucrose TMR total mixed ration VFA volatile fatty acid ix

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Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science THE EFFECTS OF NONFIBER CARBOHYDRATE SOURCE AND PROTEIN DEGRADABILITY ON LACTATION PERFORMANCE OF HOLSTEIN COWS By Colleen Casey Larson December 2003 Chair: Mary Beth Hall Major Department: Animal Sciences The effects of nonfiber carbohydrate source (NFC) and protein degradability on lactation performance, ruminal, and plasma measures were evaluated using 38 multiparous Holstein cows (82 19 DIM) in a three period partially balanced incomplete Latin square design with a 3x2 factorial arrangement of treatments. Ruminal pH, organic acid profile, and NDF disappearance in situ were evaluated with 6 ruminally cannulated cows within the group. Dietary treatments included three NFC sources (ground corn = starch = ST; citrus pulp = soluble fiber + sugar = SF; and molasses + sucrose = sugar = SU) and two concentrations of ruminally undegradable protein (+ or RUP) achieved by the addition or omission of expeller soybean meal. Diets were provided ad libitum and provided similar levels of NFC and NDF regardless of dietary treatment. Data presented are least squares means. Significant was declared at P<0.05 and tendency at 0.05
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NFC sources. Fat(3.5%) and protein-corrected milk (3.5%FPCM) yield tended to vary by NFC source with cows consuming SU having higher yields than those on SF (38.4 vs. 36.4 kg/d). Milk fat yield was not affected by dietary treatment. Milk protein yield was affected by NFC source with cows on ST yielding more protein than those on SU and SF (1.09 vs. 1.05 and 0.99 kg/d) and cows consuming SU tending to have higher protein yields compared to SF. Milk urea N and plasma urea N were higher for cows consuming ST as compared to SU and SF (13.4 vs. 12.6 and 12.5 mg/dl and 15.0 vs. 13.7 and 13.6 mg/dl) and tended to be increased for cows on RUP as compared to +RUP (13.2 vs. 12.5 mg/dl and 14.6 vs. 13.6). Feed efficiency (3.5%FPCM/dry matter intake) differed for the interaction of NFC x RUP with +RUP increasing efficiency for SU and SF while decreasing efficiency for ST. Plasma glucose (67.2 vs. 65.1 mg/dl) and insulin (0.53 vs. 0.47 ng/ml) concentrations were higher for cows fed SU as compared to SF. The molar percentage of acetate tended to be greater for SF when compared to SU (64.9 vs. 62.9%). Cows consuming SU had the highest butyrate molar percentage (11.8 vs. 10.4 and 9.38%) and lowest branch chain VFA (1.82 vs. 2.45 and 2.90%) compared to SF and ST. Additionally, cows consuming SU had the least disappearance of NDF in situ for several sampling hours. In conclusion, altering the complement of NFC together with RUP has the potential to alter lactation performance and efficiency measures. xi

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CHAPTER 1 INTRODUCTION Carbohydrates comprise approximately 65 to 75% of the lactating dairy cows diet. The two major classifications of carbohydrates in ruminant diets are neutral detergent fiber (NDF) and nonfiber carbohydrates (NFC). Among the predominant carbohydrates are cellulose and hemicelluloses in NDF and starch, pectin, and sugars in NFC (Allen, 1991). In addition to starch, pectin, and sugars (monoand oligosaccharides), organic acids (OA), fructans, and any carbohydrates soluble in neutral detergent with heat-stable, -amylase, are included in the NFC. These are considered to be highly digestible (98%) and rapidly fermentable as compared to the carbohydrates in NDF (NRC, 2001). Currently, there are general but limited recommendations guiding the use of NFC sources in diet formulations. It is essential that the digestion and yield of metabolizable nutrients from various NFC types be understood to accurately and efficiently formulate diets for dairy cattle. Improving the understanding of this large portion of the dairy cattle diet has the potential to improve animal performance and profitability while maintaining health. Carbohydrates can provide nutrients for the cow, as well as for the ruminal microbes. Microbes can use feed carbohydrates for growth, maintenance, and carbohydrate reserves. Fermentation of carbohydrates yields methane, carbon dioxide, organic acids, and microbial cells; the latter two products can serve as glucogenic, lipogenic, and protein substrates to meet the cows requirements. Starch and maltose that pass from the rumen can be hydrolyzed in the small intestine by -amylase and maltase to monosaccharides. Excepting use by small intestinal microflora, these simple sugars and 1

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2 those that escaped ruminal fermentation are absorbed by the brush border. Absorption of monosaccharides provides glucogenic nutrients for maintenance, growth, and production of the cow. Carbohydrates not digested in the small intestine pass to the cecum and large intestine where they may be utilized by the microbes to produce the same fermentation products found in the rumen. The OA produced from hindgut fermentation are absorbed readily into the blood from the lower digestive tract and may provide up to 9% of the cows energy requirement (Bergman, 1990). Current recommendations suggest that NFC be fed to dairy cattle at 30 to 45% of the diet on a dry matter (DM) basis (NRC, 2001). However, the NRC (2001) concedes that the optimal concentration of NFC in dairy cow diets is not well defined. The lack of clear recommendations may be based at least in part on the wide compositional and nutritional variation in the components included in the NFC. They vary greatly in digestion characteristics and yields of metabolizable nutrients. Until recently, practical methods were not available to measure the different carbohydrates in NFC. A recently proposed system for partitioning NFC (Hall et al., 1999) offers researchers the ability to quantitatively evaluate concentrations of starch, sugar, and neutral detergent-soluble fiber in feeds. The ability to measure these major carbohydrate fractions will allow researchers to quantitatively evaluate the animal response to them and explore the potential use for them in diet formulations. Understanding the nutritional value of each NFC type may aid in the use of all available feeds, including byproducts, to efficiently formulate dairy cow diets to enhance production and health. With knowledge of the amount of the carbohydrate fractions represented in feeds, diets may be developed that optimize the utilization of carbohydrates together with other feed fractions to provide the necessary

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3 metabolizable nutrients for the cows maintenance and production requirements and reduce nutrient excretion. Two general divisions of protein in feeds are ruminally degradable protein (RDP), which is available for degradation in the rumen by microbes, and ruminally undegradable protein (RUP), which escapes digestion in the rumen, but may have the potential to be digested in the small intestine. Two sources of protein are available for digestion in the small intestine. In addition to RUP, microbial protein also passes from the rumen and adds to the supply of protein available for digestion in the small intestine. Several factors affect the amount of feed protein that passes through the rumen undigested including: the proportional concentrations of non-protein N and true protein, the physical and chemical characteristics of the protein sources that determine their rate of digestion, and the rate of passage of feedstuffs from the rumen (NRC, 2001). The amount of microbial protein arriving at the small intestine may be influenced by RDP, and potentially, by NFC type. Different types of NFC have been shown to differ in the yield of microbial crude protein from their fermentation in vitro (Hall and Herejk, 2001). Supplying more microbial crude protein to the small intestine may decrease the need to supplement a diet with additional RUP sources. If NFC types differ in microbial yield, they may need to be complemented with different amounts of RUP to optimize nutrient supply to the cow. If these optimal concentrations can be achieved there is potential for maximizing the production of the cow while reducing excretion of N in urine and feces. The objective of this study was to evaluate the effects of three NFC sources with two concentrations of RDP/RUP on lactation performance and blood and ruminal measures. This research is intended to provide a better understanding of how various

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4 NFC and protein types can be used in diet formulation to meet the requirements of lactating dairy cows.

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CHAPTER 2 REVIEW OF THE LITERATURE ON NONFIBER CARBOHYDRATE SOURCE AND RUMINALLY UNDEGRADABLE PROTEIN IN RUMINANT DIETS Nonfiber Carbohydrates Partitioning The first system that partitioned carbohydrates was the proximate analysis or Weende system developed by Henneberg at the Weende experiment station in Germany (Maynard and Loosli, 1975). The proximate analysis system divides carbohydrates into crude fiber (CF) and nitrogen-free extract (NFE) fractions. The CF fraction includes cellulose, alkali-insoluble hemicellulose and lignin. The NFE fraction includes sugars, starches, pectin, organic acids (OA), fructans, and the alkali-soluble hemicellulose and lignin. Proximate analysis was intended to make a clear distinction between the more digestible (i.e., NFE) and less digestible (i.e., CF) carbohydrates. However, in the rumen, portions of the CF are sometimes digested and portions of the NFE are indigestible. These failings of the proximate analysis system in partitioning carbohydrates led to the development of analyses that are more nutritionally relevant. The detergent system, originally developed at the USDA (Goering and Van Soest, 1970), divides plant carbohydrates by their solubility in detergent solutions. The feed components that are insoluble in a neutral detergent solution (pH ~ 7.0) are labeled neutral detergent fiber (NDF) and include cellulose, hemicellulose, and lignin. The feed components that are insoluble in an acid detergent solution (pH ~ 2.0) are labeled acid detergent fiber (ADF) and include cellulose and lignin. These two measures of fiber 5

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6 differ by their inclusion or exclusion of hemicelluloses. The feed components that are soluble in a neutral detergent solution with heat-stable, -amylase are labeled nonfiber carbohydrates (NFC). These include mono-, di-, and oligosaccharides (sugars), starches, OA, fructans, and pectic substances (NRC, 2001) and other carbohydrates of the appropriate solubility. The detergent system is preferred over the proximate analysis system for feed analysis because separation of the most and least digestible fractions of the feeds is achieved. However, carbohydrates in the NFC fraction are not uniform in their nutritional characteristics. Further work has led to partitioning of the NFC as related to digestion characteristics. The neutral detergent-soluble carbohydrate system (NDSC) of analysis divides the NFC into OA, sugars (monoand oligosaccharides), starch and neutral detergent-soluble fiber (NDSF). Recently proposed methods (Hall et al., 1999) allow quantitative measurement of the amounts of sugars and starch and estimation by difference of NDSF in a feed. These carbohydrates appear to differ in their digestion characteristics and potential to provide metabolizable nutrients. Starch Starch is the predominant storage polysaccharide found in plants. Starch is composed of glucose (C 6 H 12 O 6 ) linked by -(1,4) linkages and -(1,6) linkages at the branch points. In its native form, starch is stored by the plant in cold water-insoluble granules of relatively crystalline structure. The two forms of starch are amylose and amylopectin. Amylose is a largely linear molecule made up of predominantly -(1,4) linked glucose molecules, while amylopectin is considerably more branched, containing -(1,6) linkages every 12 to 25 glucose residues (Zubay, 1998). Starch granules vary

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7 from 10 to 30% amylose and 70 to 90% amylopectin (Zubay, 1998) depending on the plant specie and cultivar. Depending upon a variety of factors, including processing method, starch has the potential to be fermented by ruminal microbes, however maximum starch digestion to monosaccharides requires several bacterial species working together (Huntington, 1997). Bacterial species vary in their aptitude for digesting starch at different points in the granule. Bacteria that can hydrolyze the -(1,6) linkages can provide substrates for bacteria that may only have the ability to hydrolyze -(1,4) linkages. These bacteria include, but are not limited to, Streptoccocus bovis, Butyrivibrio fibrisolvens, Bacteriodes ruminicola, and Selenomonas ruminatium (Huntington, 1997). Starch that is not degraded and utilized by ruminal microbes may be digested in the intestines. The pancreas secretes -amylase which breaks down amylose and amylopectin into linear oligosaccharides and limit dextrans. The amount of starch digested post-ruminally can vary from 5 to 20% of starch from the diet with most of that being digested in the small intestine (Streeter et al., 1989, 1991; Hill et al., 1991; Zinn, 1991). Corn, wheat, oats, barley, sorghum, and many by-products such as hominy and bakery waste are common feedstuffs that have high starch contents. Corn contains an average of 72% of DM as starch (Huntington, 1997), which has the potential to be highly digestible and rapidly fermented in the rumen. Total tract digestibility of corn ranges from 91.2 to 98.9% depending on the processing method and grain type, with ground corn averaging 93.5% (Huntington, 1997). If a starch source is rapidly fermented and represents a large portion of the diet, ruminal acidosis can develop, which can cause

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8 digestive upset and a depression in intake and digestibility of other nutrients (Nocek, 1997). Management practices that promote consumption of large meals in a short time frame and heat stress conditions also may contribute to ruminal acidosis. Huntington (1997) proposed that almost all of the adversities associated with feeding high-grain diets are caused by excessively rapid fermentation of starch to OA. These OA include acetate, propionate, and butyrate, as well as lactate. High starch diets have been associated with relatively increased propionate and decreased butyrate concentrations (Strobel and Russell, 1986; Friggens et al., 1998; Heldt et al., 1999) Sugars The term sugars is used collectively to describe mono-, di-, and oligosaccharides. These are comprised of one, two, or less than twenty monosaccharide (typically hexose or pentose) residue molecules, respectively (Zubay, 1998). Functionally, sugars encompass the carbohydrates soluble in 78 to 80% ethanol (Asp, 1993). These sugar residues include but are not limited to glucose, fructose, galactose, mannose, ribose, and xylose. Glucose and fructose are the most common monosaccharides found in plants. Sucrose, the most common disaccharide found in plants, is composed of glucose -(1,2) -fructose (Zubay, 1998). Sucrose, fructose, and glucose are found in relatively high amounts in molasses, a common cattle feed. Samples from U. S. Sugar Corporation in Clewiston, Florida from 1997 to 2003 averaged 48.3% total sugar as invert (as-fed) with 23.7% moisture (personal comm., Dr. Chet Fields, 2003). Another feed that can have a high content of sugars is citrus pulp, but the content is quite variable. Measured values of sugars in citrus pulp range from 12% to 40% on a dry matter (DM) basis (Hall, 2002). As with other fermentable carbohydrates, fermentation of sugars can alter the ruminal environment as well as the supply of metabolizable nutrients to the cow.

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9 Bacteria and protozoa are known to convert a portion of sugars to glycogen (-linked storage polysaccharide in bacteria) (Thomas, 1960). The fermentation of sugars in vitro or in vivo shows variation among sugar sources in the yield of products and effects on the ruminal environment, and differences with other NFC sources. The digestion of oligosaccharides, a relatively small part of the sugars in plant material, has not been extensively studied or described; consequently this thesis will focus on the predominant monoand disaccharides in feeds (glucose, fructose, and sucrose). These very small molecules are typically very readily solubilized and digested. Using trichloroacetic acid-precipitated crude protein (CP) as an estimate of microbial CP, Hall and Herejk (2001) showed that sucrose differed from corn starch and citrus pectin in the temporal pattern of microbial CP yield when fermented with isolated bermudagrass NDF. Peak microbial CP production from the fermentation of sucrose was reached within 12.6 hours of fermentation and CP yields were maintained similar to the peak value through 20 hours of fermentation. In contrast, starch and pectin fermentations peaked later (hours 15.6 and 13.5, respectively) than sucrose, and the yield of microbial CP began to decline by the next sampling point, post-peak. Sucrose, glucose, and fructose have been shown to have increased butyrate and slightly decreased propionate yields relative to starch (Strobel and Russell, 1986; Heldt et al., 1999). Friggens et al. (1998) found that molasses increased butyrate concentrations followed by soybean meal, sweet potato, wheat, and field beans. In other studies with greater than 15% of the dietary DM as sucrose or molasses, molar proportions of butyrate and propionate in the ruminal fluid increased whereas acetate decreased and ruminal pH was depressed within 1 h after feeding (Khalili and Huhtanen, 1991; Moloney et al., 1994). The depression in

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10 pH has not been observed where sucrose or molasses made up less than 12% of the diet DM (Huhtanen, 1988; Petit and Veira, 1994; Maiga et al., 1995). As compared to other carbohydrates, fermentation of sugars has shown greater potential to yield lactate (Cullen et al., 1986; Strobel and Russell, 1986; Heldt et al., 1999). When fermenting glucose, Piwonka and Firkins (1996) found that a decreased rate of NDF digestion was caused by the residual effect of a proteinaceous inhibitor. An in vitro study that evaluated the effects of sucrose and lactose at three concentrations reported limited effects of these sugars on ruminal measures. McCormick et al. (2001) conducted an in vitro fermentation using three concentrations of sucrose and lactose (0, 2.5, and 5% of substrate DM) in combination with solvent soybean meal (SSBM) or expeller soybean meal (ESBM). The smallest NH 3 -N concentration in the media was from the 5% sucrose supplement (P = 0.06) (Table 2-1). Greater concentrations of NH 3 -N were observed from the SSBM as compared to the ESBM (P = 0.01). Concentrations of lactate, acetate, propionate, and total OA were not affected by the protein or sugar treatments. Butyrate concentration tended to be greater for the media containing ESBM and no supplemental sugars than that for SSBM and the five percent sugars (P = 0.07 for protein, P = 0.10 for sugars) (Table 2-1). There was no indication given that the ruminal microbes used as inoculum had been acclimated to galactose prior to collection from the donor animal. It is unknown if the results would have differed if the ruminal microflora had been adapted to lactose. The complement of dietary OA and sugars may alter volatile fatty acid (VFA) yield and pH when starch is fed. Martin et al. (2000) used one ruminally cannulated steer fed 36.3 kg/d of wheat silage and 4.5 kg/d of concentrate supplement to collect ruminal fluid

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11 for an in vitro study. The ruminal contents were collected 1.5 h after feeding and added to a pH 6.5 medium. Two concentrations of sugar plus malate (SM) (a commercial feed supplement) were fermented alone or with ground corn or soluble starch at 0.0, 2.25, or 3.25 g/L. In the absence of added corn or starch, both concentrations of SM decreased final pH (P < 0.05) and increased total VFA, acetate, propionate, and butyrate (P < 0.05) (Table 2-1). For the ground corn fermentation, additions of SM increased concentrations of acetate, propionate, and total VFA (P < 0.05) while the greatest level of SM (3.25 g/L) actually decreased the final pH and butyrate concentrations (P < 0.05). Both concentrations of SM increased concentrations of acetate, propionate, and total VFA when soluble starch was included in the fermentation. In contrast, concentrations of butyrate were reduced when soluble starch was added at 3.25 g/L compared to the control (P < 0.05). Differences in fermentation characteristics and effects on fiber digestibility challenge the notion of the equivalence of starch, monoand disaccharides. An interaction with dietary supplementation of ruminally degradable protein (RDP) also appears to alter the impact of the NFC source. Ruminally degradable protein is protein that is available for use by the ruminal microbes. Heldt et al. (1999) fed twenty ruminally fistulated Angus x Hereford steers (average BW = 449 kg) in two consecutive randomized complete block experiments. Cattle had ad libitum access to low-quality tall-grass prairie hay. The five dietary treatments were no carbohydrate supplement, starch, glucose, fructose, or sucrose fed at 0.30% of bodyweight (BW)/d with RDP (sodium caseinate 91.6% CP) at 0.031% of BW/d (experiment 1) or 0.122% of BW/d (experiment 2). Ruminal pH and apparent total tract digestibilities of organic matter (OM) and NDF

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12 were not affected by supplemental NFC when feeding the low RDP diet (experiment 1). However, concentrations and type of OA in the ruminal fluid were dependent on the type of NFC fed. At low levels of RDP supplementation (0.031% of BW), the greatest OA concentration was reported with sucrose. The smallest concentration was in steers fed the monosaccharides, fructose and glucose (P = 0.05; divs. monosaccharides) with steers fed starch having numerically intermediate concentrations between those fed the monoand disaccharides (P = 0.41 for starch vs. sugars) (Table 2-1). Starch yielded the greatest concentrations of acetate (P < 0.01) and propionate (P = 0.11), but less butyrate (P < 0.01) as compared to the sugars. Steers fed fructose and glucose had greater molar proportions of acetate than did sucrose (P = 0.05) (Table 2-1). Isobutyrate and isovalerate, the branched chain volatile fatty acids (BCVFA), proportions were decreased in steers fed the sugar diets as compared starch (0.83 and 1.02 respectively, P < 0.01) and tended to be even smaller yet for the monosaccharides (glucose and fructose averaged, 0.53 and 0.45 mol/100 mol, P<0.09) as compared to sucrose (0.67 and 0.65 mol/100 mol). At the greater (0.122% BW/d) concentration of RDP in experiment 2, ruminal pH was lesser for the starch supplemented cattle as compared to those supplemented with sugars (P = 0.04) (Table 2-1). Total OA were greater for starch as compared to glucose, fructose, and sucrose (P = 0.05). Again, ruminal acetate and propionate proportions were greater in steers fed starch as compared to those fed sugars (P < 0.01 for starch vs. sugars) (Table 2-1). Butyrate values were again greater with sugar compared to starch supplementation (P < 0.01). Isobutyrate and isovalerate proportions were greater for starch (0.82 and 1.13 mol/100 mol) as compared to sugars (glucose, fructose, and sucrose

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13 averaged, 0.67 and 0.94 mol/100 mol, respectively, P = 0.02 and P = 0.07, respectively), but monoand disaccharides did not differ in these BCVFA. Apparent digestibilities of OM and NDF were lesser for starch supplemented diets (66.7 and 61.2%, respectively) compared to the sugar supplemented diets (glucose 73.1 and 68.1%, fructose 75.2 and 71.3%, and sucrose 67.7 and 62.3%, respectively) (OM P = 0.04 and NDF P = 0.05, for starch vs. sugars). The diets with monosaccharides also had greater OM and NDF digestibility than those with sucrose (OM P = 0.02 and NDF P = 0.03). The authors concluded that feeding limited quantities of supplements that contained RDP and starch or sugars to cattle consuming low-quality forage will improve total digestible OM intake. Another study that evaluated the effects of sugar and starch on ruminal measures was that of Piwonka and coworkers (1994). In that study six cannulated heifers were fed three diets in a 3 x 3 Latin square design. The diets were high forage, high forage with dextrose (5.6% of dietary DM), and a medium concentrate and forage diet (60.3% forage and 39.7% barley, DM basis). Forage was supplied by orchardgrass hay and corn silage. Barley was increased to achieve the medium concentrate diet (4.40 and 39.7% of DM for dextrose and medium concentrate, respectively). Reported nonstructural carbohydrate concentrations were 25.l% for the high forage diet, 27.2% for the high forage with dextrose diet, and 34.9% for the medium concentrate diet (% of dietary DM). Total VFA concentrations were not different between the heifers fed dextrose and concentrate diets (P > 0.05) (Table 2-1). Additionally, ruminal acetate, propionate, and butyrate concentrations did not differ by carbohydrate treatment (P > 0.05). Ruminal NH 3 N concentration was greater for the cows consuming dextrose as compared to those consuming the medium concentrate diet (P < 0.05) (Table 2-1). Mean ruminal pH did

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14 not differ by treatment and remained above 6.0 for all of the diets. Rate of NDF digestion was greater for the cows consuming the dextrose diet compared to the medium concentrate (0.0586 vs. 0.0442 h -1 respectively, P < 0.05). Extents of NDF and OM apparent total tract digestibility did not differ by treatment. Apparent ruminal OM digestibility as a percentage of intake was also greater for heifers consuming the dextrose diet than the medium concentrate (38.1 vs. 25.7%, respectively, P < 0.05). Efficiency of bacterial growth (measured as grams of bacterial N per kilogram of OM truly digested in the rumen) was greater for the heifers consuming the medium concentrate diet compared to those fed dextrose (37.5 vs. 23.8, respectively, P<0.05). This probably occurred because a constant and greater supply of ruminally available carbohydrates for microbial growth without pH depression should allow more efficient capture of NH 3 -N (Nocek and Russell, 1988). Pectic Substances and Pectin Neutral detergent-soluble fiber includes the non-starch, non-NDF polysaccharides that have no covalent linkage with lignin, are soluble in neutral detergent, and are completely available to fermentation (Van Soest, 1994). The NDSF contain carbohydrates from both plant cell contents (fructans) and plant cell wall (pectic substances, mixed linkage -glucans). Pectic substances are one of the most prevalent types of soluble fiber in forages and feeds not of grass origin. There is not a clear distinction between pectic substances and hemicelluloses, because portions of each can appear in the chemical analysis for the other (Van Soest, 1994). This complicates the determination of the absolute amount of pectic substances present in a sample. We will focus on the neutral detergent-soluble fraction of pectic substances.

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15 Pectic substances, a polysaccharide rich in galacturonic acid, is found in the middle lamella and other cell wall layers in the plant. It is made up of a galacturonic acid chain, linked -(1, 4), interrupted and bent by frequent rhamnose units that may have arabinan or galactan side chains attached (Jarvis, 1984). The carboxyl groups on the galacturonic acid residues can be combined with calcium ions or as methyl esters. The pectic polysaccharides can form large aggregates if calcium is available in excess (Jarvis, 1984). In contrast to pectic substances, pectin largely represents the galacturonic acid backbone without the neutral sugar side chains. Starch is hydrolyzed by amylase, whereas pectins are hydrolyzed by pectinesterases and pectinglycosidases (Dehority, 1969). Some feeds that contain a relatively high concentration of pectin are citrus pulp, beet pulp, soybean hulls, and forage legumes. Citrus pulp, a by-product of the citrus juice industry, is a common dairy feed in the Southeast. Citrus pulp is comprised of the fruit and other plant material (leaves, stems, etc.) that remain after the juice is extracted from the fruit. Citrus pulp contains 25 to 44% NDSF (Hall, 2002). As compared to alfalfa, apple, and sugar beet pectin, citrus pectin has the greatest percent of polygalacturonic acid at 98.4% and the greatest degree of esterification (Kasperowicz, 1994). The structural carbohydrate, pectin, is degraded by three groups of bacteria (Kasperowicz, 1994). First, there are bacterial species that degrade pectin and/or use the degradation products. Second are the bacterial species that degrade pectin but can only use the simple sugars. Finally, the third group consists of bacteria that cannot degrade pectin, but utilize the oligogalacturonides and galacturonic acid from the degradation of pectin. Prevotella ruminicola, Butyrivibrio fibrisolvens, and Lachnospira multiparous

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16 make up the first group of bacteria (Stewart and Bryant, 1988). Streptococcus bovis falls in the second group, while Selenomonas ruminantium and Fusobacterium belong to the third group (Tomerska, 1971; Ziolecki et al., 1972). Gradel and Dehority (1972) showed that pure strains of P. ruminicola, L. multiparous, and B. fibrisolvens were able to ferment up to 80% of citrus pectin. Pectin has been shown to yield relatively high amounts of acetic acid compared to other carbohydrate sources (Strobel and Russell, 1986). Citrus pectin yielded the greatest concentration of acetic acid in vitro when compared to lucerne, apple, and sugar beet pectin, although the main end product of fermentation of all of the pectins was acetate (Kasperowicz, 1994). Hatfield and Weimer (1995) showed that fermentation of citrus pectin gave an increased acetate to propionate ratio as compared to lucerne pectin, and they reported an increased yield of acetate from citrus pectin and increased propionate from lucerne pectin. Marounek and Duskova (1999) grew B. fibrisolvens and P. ruminicola in cultures with D-glucose or pectin and found that strains grown on pectin produced more acetate and less butyrate and lactate. Schaibley and Wing (1974) noted an increase in molar proportion of acetate (64.0 to 70.6% from diets with 0 to 82% of dietary DM as citrus pulp, respectively) and a decrease in propionate proportion (13.1 to 11.5% from diets with 0 to 82% of dietary DM as citrus pulp, respectively) in ruminal fluid when feeding increasing concentrations of citrus pulp. Using continuous culture techniques, Mansfield et al. (1994) reported an increase in molar proportions of acetate and no difference in total VFA and propionate (Table 2-1). Lees et al. (1990) evaluated ruminal measures by week of lactation and found that in week 9 and 16 the ruminal VFA proportions of cows fed sugar beet pulp were greater for acetate and butyrate and lesser

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17 for propionate compared to cows fed maize. They also found that cows consuming maize-based diets had greater plasma insulin concentrations than those consuming the sugar-beet pulp based diet. Varying dietary carbohydrate source can result in different fermentation patterns in the rumen, influencing the hormonal status of the animal and potentially affecting the response in milk production (Lees et al., 1990). In contrast, Van Vuuren et al. (1993a) did not detect a difference in ruminal fluid pH or VFA concentrations in either experiment conducted with cows fed corn products or sugar beet pulp and soybean hulls. Pectin-rich feeds have differed from other NFC sources in their support of production of microbial CP. Hall and Herejk (2001) showed that fermentation of pectin plus NDF resulted in decreased peak microbial CP yield than did starch plus NDF but followed a similar pattern of growth. When comparing different pectin sources, Kasperowicz (1994) concluded that the amount of bacterial protein synthesized was more dependent on the species of bacteria than the type of pectin fermented. Kasperowicz (1994) also observed that the depletion of polygalacturonic acid, extent of bacterial protein synthesis and amount of pectin fermented to end products was the greatest from citrus pectin, likely due to its simple structure and accessibility to bacterial enzymes. The consumption of diets rich in pectin sometimes had positive effects on ruminal digestion. Ben-Ghedalia et al. (1989) found that replacing barley with citrus pulp in sheep diets resulted in a less acidic pH and increased acetate concentration in ruminal fluid but a decrease in total VFA and proportion of propionate, valerate, isobutyrate, and isovalerate (Table 2-1). Ben-Ghedalia et al. (1989) concluded that compared to starch, citrus pulp created more favorable conditions for microbial utilization of other

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18 carbohydrates in the rumen at least in part due to a more neutral pH. Strobel and Russell (1986) incubated starch, sucrose, pectin, and a mixture of carbohydrates at a pH of 6.0 or 6.7. Fermentation of all NFC sources was decreased at the lesser pH. Evaluation of starchor pectin-rich total mixed rations (TMR) in continuous culture provided information on fermentation products as well as on microbial efficiencies. Ariza et al. (2001) compared two dietary treatments that contained hominy feed or dried citrus pulp in continuous culture. The hominy diet contained starch at 24% of dietary DM and the citrus pulp diet included NDSF at 14.4% of dietary DM. Concentrations of CP, NDF, and NDSC were similar for both diets. A greater acetate proportion was achieved on the citrus pulp diet (P = 0.03) whereas the hominy diet yielded the most propionate (P = 0.02) (Table 2-1) and BCVFA (3.7 vs. 3.0 mol/100mol, P = 0.03). The acetate to propionate ratio was expectedly greater from the citrus pulp diet as compared to the hominy diet (4.1 vs. 2.8, respectively, P = 0.01). Digestibilities of OM, NDF, ADF, starch, NDSF, and NDSC did not differ by dietary treatment. Greater concentrations of NH 3 -N were detected from the hominy diet as compared to the citrus pulp diet (P = 0.01) (Table 2-1). The efficiency of microbial synthesis tended to be greater for the citrus pulp diet as compared to the hominy diet. Bacterial synthesis measured as g of N/kg of OM truly digested was 30.6 for citrus and 27.8 for hominy (P = 0.06). Bacterial synthesis measured as g of bacterial N/g of available N was 80.1 for citrus and 68.3 for hominy (P = 0.09). Effects of Starch, Sugars, and Pectin on Animal Response Performance measurements such as dry matter intake (DMI), milk yield, milk components, and feed efficiency have varied when replacing starch with soluble fiber (primarily pectin) or sugar sources. The two major pectin-rich feed sources used in

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19 studies were sugar beet pulp and citrus pulp; molasses and sucrose were the most commonly used sugar supplements. Cattle consuming diets containing pectin-rich feeds have been shown to increase intake (Valk et al., 1990; Lees et al., 1990; Chester-Jones et al., 1991), while including sugars in diets occasionally has resulted in increased intake (Maiga et al., 1995; Broderick et al., 2002a). When compared to performance on diets containing more starchy feeds, cows consuming pectin-rich feeds had decreased milk yield (Van Horn et al., 1975; Leiva et al., 2000; Broderick et al., 2002b) and milk protein percentage (Mansfield et al., 1994; Leiva et al., 2000; Solomon et al., 2000; Broderick et al., 2002b) while increasing milk fat concentration (Lees et al., 1990; Mansfield et al., 1994). The increase in milk fat (concentration or yield) by replacing starch with pectin-rich feeds has not been observed in other studies (Leiva et al., 2000; Solomon et al., 2000). Supplementation of sugars has decreased milk protein yield (Sannes et al., 2002) and percentage (Nombekela and Murphy, 1995) and decreased milk fat yield (Sannes et al., 2002) compared to starch. In contrast, supplementation of sugars has raised milk fat yield (Broderick and Radloff, 2002; Broderick et al., 2002a) and shown no effect on protein yield (Maiga et al., 1995; Broderick and Radloff, 2002; Broderick et al., 2002a). Still other studies reported no difference in DMI or milk production by varying NFC type (Fegeros et al.,1995; Malestein et al., 1984). It is not known to what extent varying the concentration, types, and combinations of NFC may alter lactation performance and blood and ruminal measures. The influence of sugar and starch feeding on products of ruminal fermentation, milk composition, and intake was demonstrated by the work of Sannes et al. (2002). The diets contained 17% CP (DM basis), fed with corn at 20% of dietary DM or a

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20 combination of corn and sucrose (13.5 and 3.2% of dietary DM, respectively). Diets were based on corn silage and alfalfa. Total VFA, acetate, propionate, and butyrate concentrations were not affected by dietary treatment (Table 2-1). Branch chain VFA concentrations were decreased for the sucrose compared to the corn treatment (1.34 vs. 1.87 mM, P = 0.02). Cows consuming sucrose tended (P = 0.08) to have lesser NH 3 -N concentrations than those consuming the diet without sucrose added (Table 2-1). Milk fat and protein yields were greater for the cows consuming the corn as compared to those consuming the sucrose treatment (P = 0.05) (Table 2-2). Additionally, milk urea N concentration (MUN) tended (P = 0.06) to be greater for the sucrose treatment compared to the corn (Table 2-2). The authors concluded that achieving a beneficial response to sucrose supplementation may require additional dietary RDP to avoid NH 3 limitation. The effects of replacing starch with sugar on intake, milk composition and ruminal measures were evaluated by Broderick and Radloff (2002). Forty-eight (8 cannulated) Holstein cows were fed one of four diets based on alfalfa silage. The diets contained the following levels of sugars and starch, respectively: 2.6 and 31.3% (0% molasses), 4.2 and 28.4% (4.0% molasses), 5.6 and 25.2% (8.0% molasses), or 7.2 and 23.2% (12% molasses) on a DM basis. Diets were isonitrogenous, and contained similar concentrations of NDF and NFC. High moisture shelled corn provided starch while dried molasses was used to vary the amount of sugars. They found that DMI increased linearly with increasing sugars (P = 0.04) (Table 2-2). However, since milk and milk protein yields did not follow the increase in DMI, efficiencies of DM and nitrogen utilization (milk/DM intake of 1.51 to 1.43 and milk N/N intake of 0.255 to 0.231, P = 0.03 and P = 0.02, respectively) decreased linearly. There was a significant quadratic response for

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21 3.5% fat-corrected milk (FCM) and fat yield (Table 2-2) with the maximum at 3.5% dried molasses in the diet (P = 0.04 for FCM and P = 0.03 for fat yield). Ruminal ammonia showed a quadratic effect reaching the smallest concentration when 6.1% dried molasses was added (P = 0.05) (Table 2-1). The addition of sugars also resulted in a linear decrease in BCVFA (P = 0.05). Molar proportions of butyrate tended to increase linearly with the added molasses (P = 0.10). The effects of replacing starch with sugars using purified substrates were assessed by Broderick and coworkers (2002a). Forty-eight Holstein cows were fed diets based on alfalfa silage and contained the following amounts of starch and sugar, respectively: 28.2 and 2.7%, 27.4 and 5.1%, 24.5 and 7.1% or 21.5 and 10.0%. These concentrations were achieved by feeding decreasing dietary proportions of cornstarch and increasing dietary proportions of sucrose. Diets were isonitrogenous and contained similar concentrations of NDF and NFC. While DMI increased linearly with the addition of sucrose (P = 0.01) (Table 2-2), there were not subsequent increases in milk production. However, milk fat yield (P = 0.05) and percentage (P = 0.01) increased linearly with sucrose addition, with milk fat percentage increasing from 3.8 to 4.2% from no sucrose to 7.5% sucrose, respectively. In this study, ruminal concentrations of propionate increased (P = 0.04) (Table 2-1) and BCVFA decreased (P = 0.02) with the addition of sucrose to the diets. In contrast to other studies that fed sugars, no change in ruminal butyrate concentrations were detected in this study. The prepartum feeding of sucrose had small effects prepartum but no detectable carryover effects in lactation. In the study of Ordway et al. (2002), thirty-four multiparous lactating Holstein cows were fed diets of 0 or 2.7% sucrose (DM basis) with

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22 sucrose partially replacing ground corn (11.5% of dietary DM as ground corn). Cows began consuming diets at 30 d prior to expected calving date and were switched to a lactating cow diet upon calving. Both diets contained corn silage, cottonseed hulls, corn cobs, soyhulls, alfalfa dehydrate, soybean meal, liquid molasses, protein mix and a mineral mix. Diets were isonitrogenous with similar concentrations of NFC and NDF. The control diet contained 21.8 and 6.6% of DM as starch and sugars compared to the sucrose diet with 20.4 and 8.8% of DM starch and sugars, respectively. Dry matter intake, body weight, and body condition score were not affected by sucrose treatment. Plasma glucose tended (P = 0.08) to be greater prepartum for the cows provided the sucrose diet as compared to the control (Table 2-2). Feeding sucrose did not affect DMI, insulin, and blood urea N preor postpartum or milk production and milk composition postpartum. While sucrose supplementation increased blood glucose concentrations prepartum, suggesting absorption of additional glucogenic precursors, a response in lactation performance was not detected. Although not statistically significant, cows supplemented with sucrose appeared to have less periparturient health problems. Numerically, the sucrose-supplemented cows had less incidence of ketosis (4 of 16 in the control group and 1 of 18 in the sucrose group). Maiga et al. (1995) demonstrated that feeding of sugar sources with fat altered lactation response. Forty Holstein cows (28 primiparous and 12 multiparous) were fed one of the following diets; control, fat (tallow at 2% of dietary DM), molasses plus fat (8.3% of diet as liquid feed containing molasses plus 19% fat of DM), or dried whey plus fat (whey at 5.4% and tallow at 2.0% of dietary DM). All diets contained corn silage, alfalfa hay, shelled corn, and soybean meal. Diets contained similar concentrations of

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23 CP, NDF and total nonstructural carbohydrates. Milk fat and protein percentage tended to be greater for the cows fed the tallow diet without sugar as compared to those fed the molasses plus fat and the dried whey plus fat diets (fat: 3.65 vs. 3.53 and 3.40%, respectively, P = 0.10; protein: 2.98 vs. 2.91 and 2.86%, respectively, P = 0.07). Feed efficiency was greatest for the tallow (1.49, P = 0.04 for tallow vs. molasses and dried whey plus fat) followed by the dried whey plus fat (1.46) and then the molasses plus fat (1.39) (P = 0.05 for molasses plus fat vs. dried whey plus fat). There were no differences in yields of milk, 3.5% FCM, or DMI between the fat-supplemented diets. Mean ruminal pH tended to be decreased for the molasses plus fat compared to the dried whey plus fat (P = 0.06) (Table 2-1). Although not statistically significant (P = 0.11), total VFA concentration was greater for the molasses plus fat compared to the dried whey plus fat (Table 2-1). Butyrate concentration was greater for cows fed the molasses and dried whey plus fat diets as compared to the tallow diet (13.2 and 12.9 vs. 12.5 mol/100 mol, respectively, P = 0.03). Low inclusion of sucrose substituted for corn meal modified milk composition in a study by Nombekela and Murphy (1995). Twenty-four Holstein cows were fed a control diet or a diet with sucrose at 1.5% of dietary DM. The sucrose replaced 1.5% of DM of ground corn. Dry matter intake (measured as kg/d, % of BW, and g/kg of BW 0.75 ), milk yield, and 3.5% FCM were not affected by dietary treatment of sucrose supplementation. Milk protein concentration was greater for the cows consuming the control diet as compared to the sucrose supplemented diet (3.51 vs. 3.28%, P<0.01). Milk fat yield tended to be greater for the sucrose supplemented cows as compared to those consuming

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24 the control diet (P = 0.07) (Table 2-2). Feed efficiency (3.5% FCM:DMI, kg/kg) was not affected by dietary treatment. Variability in the effects of feeding starchor pectin-rich diets on lactation performance was illustrated in studies by Leiva et al. (2000). In this study cows were fed one of two diets with the NFC fraction providing predominately either citrus pulp (CPD) or hominy (HD). Eleven multiparous Holstein cows including three ruminally cannulated were evaluated in a two period reversal design. All diets contained corn silage, alfalfa hay, cottonseed hulls, distillers grains, soybean meal, whole cottonseed and a mineral mix in addition to the NFC sources. The average concentrations of CP and NDF for the diets were 17.9 and 36.1% (DM basis), respectively. Starch made up 15.1% (CPD) and 26.5% (HD) of the diets on a DM basis. Sugars were 4.8% of DM in the CPD and 2.5% of DM in the HD diets. Intakes in kg/d of DM, CP, and NDF were all similar with cows on the CPD diet consuming more sugars and NDSF and cows on the HD consuming more starch (P<0.01). Yields of milk, 3.5% fatand protein-corrected milk (FPCM), fat, and protein, and fat percentage were not affected by dietary treatment. Only milk protein percentage differed by diet, with cows on the HD diet having an increased protein concentrations than those on CPD (P = 0.01) (Table 2-2). Feed efficiency (3.5% FPCM/DMI, kg/kg) also was not different by treatment (1.45 vs. 1.47 for CPD and HD respectively, P = 0.65). Ruminal pH, and concentrations of total VFA, acetate, propionate, butyrate, and lactate did not differ by dietary treatment. When replacing maize with sugar beet pulp, milk fat and fat-corrected milk yields have increased. Lees et al. (1990) fed twelve Friesian cows and sixteen heifers a high fiber or high starch concentrate supplement fed with low (1.8% urea as-fed) or high

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25 protein (24.0% soybean meal and 6.0% fishmeal as-fed). All diets contained hay and barley. The high fiber, low and high protein supplements contained 35.0 and 24.5% sugar beet pulp, 35.2 and 24.5% barley, and 18.0 and 12.5% ground maize (as-fed), respectively. The high starch, low and high protein supplement contained 40.2 and 28.0% flaked maize, 31.8 and 22.2% barley, and 16.2 and 11.3% ground maize (as-fed), respectively. Cows fed the sugar beet pulp had greater DMI than cows fed the maize diet (P < 0.05) (Table 2-2). Milk fat percentage (3.9 vs. 2.8%) and FCM (20.3 vs. 17.9 kg/d) were also increased (P < 0.05) with feeding sugar beet pulp, while milk yield was not (Table 2-2). In an early study, Van Horn et al. (1975) fed 36 cows (Holsteins, Jerseys, and Guernseys) diets containing 5% molasses, 25% sugar cane bagasse and urea or soybean meal. Changing NFC source was accomplished by replacing ground corn with either 8 or 43.1% of dietary DM with dried citrus pulp. Cows fed the high corn diet produced more milk (Table 2-2) and had a decreased milk fat percentage (3.41 vs. 4.41%) than those consuming the high citrus diet. Dry matter intake and milk protein percentages were not affected by dietary treatment. Even within the same experiment station, animal intake response to supplementation with starchor pectin-rich feeds has not always differed, although changes in digestibilities have been observed. Van Vuuren et al. (1993a) conducted two separate experiments comparing the effects of corn products vs. sugar beet pulp. In experiment 1, the three diets fed to Dutch Friesian multiparous cows were ryegrass alone, ryegrass supplemented with corn meal and hominy (47.5 and 50% of supplement, respectively, DM basis) and ryegrass supplemented with sugar beet pulp and soybean

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26 hulls (82.5 and 15.0% of supplement, respectively, DM basis). For both carbohydrate sources supplemented, intake of OM increased by 0.2 to 0.3 kg/d. In experiment 2, corn silage replaced perennial ryegrass. Increasing the proportion of corn meal (0, 44, or 87.5% DM basis) or sugar beet pulp (0, 44, or 78.5% DM basis) in the supplement did not affect OM intake. Although intake remained unchanged, Van Vuuren et al. (1993b) reported a digestibility response when feeding three Dutch Friesian multiparous lactating cows fitted with ruminal and duodenal cannulas one of three experimental diets. The diets were the following: grass (14.5 kg/d of DM), grass with a starch supplement (9.3 and 5.3 kg/d of DM, respectively), and grass with a fiber supplement (9.4 and 5.4 kg/d of DM, respectively). The starch supplement contained 47.5% corn meal and 50.0% hominy, whereas the fiber supplement contained 82.5% sugar beet pulp and 15.0% soybean hulls (% of concentrate, DM basis). Dry matter intake and ruminal OM digestibility were not affected regardless of supplement type. Ruminal digestibility of NDF increased from 74.5 to 79.2% when starch was replaced with the fiber supplement. A study with beef cattle demonstrated a positive intake response to feeding pectin-rich feeds. Chester-Jones et al. (1991) fed beef steers one of six diets containing three different concentrations of sugar beet pulp and two soybean products as the protein sources. Diets contained either 10% soybean meal or 9.4% alcohol-treated, defatted soybean flakes (DM basis) with 0, 15, or 30% sugar beet pulp (DM basis). All diets were fed with corn, alfalfa pellets, urea, and a mineral mix. The DMI was greatest for steers fed the 15% beet pulp diet when soybean meal was the main protein source. When beet pulp was increased to 15%, DMI increased 0.43 kg/d. Intake increased linearly with increasing dietary concentration of sugar beet pulp when soybean flakes were the main

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27 protein source. Regardless of protein source, feed efficiency (kg of DMI/kg of gain) decreased linearly with increasing sugar beet pulp in the diet. Average daily gains were not affected by beet pulp treatment. In two conflicting studies, Valk et al. (1990) reported intake increases from starchy feeds and then from pectin-rich feeds. In trial 1, Valk et al. (1990) fed multiparous lactating cows fresh ryegrass (17.5% CP and 14.6% sugar) with a fibrous (beet pulp) or starchy (maize) supplement. Cows fed maize consumed 0.6 kg/d more DM and produced 2.6 kg/d more milk than cows fed beet pulp. In trial 2, an equal mix of maize and beet pulp constituted a third type of supplement (fibrous/starchy) and again the forage source was ryegrass (21.4% CP and 11.3% sugar). Dry matter intake was greatest for cows fed the most beet pulp. Digestibility of NDF was greater for the cows fed beet pulp as compared to those fed maize meal (70.8 vs. 66.1%). Yields of milk, fat, and protein were not different by type of supplementation (Table 2-2). Differences in the quality of ryegrass may have contributed to the conflicting results in trials 1 and 2, although the in vitro OM digestibility of both cuttings was 81%. A study with sheep found no change in lactation performance with feeding citrus pulp. Fegeros et al. (1995) conducted a study with 26 lactating ewes. They received 700 g of alfalfa hay, 300 g of wheat straw, and 550 or 580 g of concentrate with 0 or 30% citrus pulp, respectively. Dried citrus pulp replaced portions of grains (maize and barley), soybean meal, and wheat middlings. No effect of dietary treatment was detected on DMI, milk yield, FCM yield or milk fat and protein content. In contrast to other studies with lactating dairy cows, Friggens et al. (1995) detected no differences between feeding starch-and pectin-rich diets. In that study

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28 eighteen lactating Friesian cows (126 days in milk) were fed diets containing hay (8.9% CP and 73.4% NDF) and concentrate in a 40:60 ratio (DM basis). The three concentrate treatments were the following: 1) 0% sugar beet pulp, 56.4% barley grain, and 20% ground corn, 2) 37.3% sugar beet pulp, 28.2% barley grain, and 10% ground corn, and 3) 74.5% sugar beet pulp, 0% barley grain, and 0% ground corn. Dry matter intake was not reported in this study. Feeding increasing amounts of sugar beet pulp had no effect on milk yield, milk composition, body condition, or body weight. Changing the dietary source of NFC fed to lactating dairy cows has been shown to alter the ruminal environment. Though not always consistent, effects have been observed on proportions of VFA, concentration of rumen NH 3 -N, and extent of fiber digestion with feeding starch, sugars or pectin-rich feeds. These changes in ruminal characteristics likely altered the flow of potentially metabolizable nutrients to the cow throughout the digestive tract. Altering the nutrients provided to the cow may have the potential to change milk production and composition. Effects of RUP and NFC Source in Ruminant Diets Ruminally undegradable protein (RUP), also called undegradable intake protein and bypass protein, is feed protein that escapes microbial degradation in the rumen; it may or may not be digested and absorbed in the small intestine. Digestion of RUP and microbial CP in the small intestine provides metabolizable amino acids to the cow. Other than urea, most feeds that contain N have some RUP; some feeds having relatively greater concentrations than others. The latter include heated and/or treated soybean products, fish meal, meat and bone meal, blood meal, feather meal, and brewers and distillers grains. There is great variation in the digestibility of these products in the small intestine, as well as in the results in feeding studies. Santos et al. (1998) reviewed 88

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29 lactation studies from 1985 to 1997 and found inconsistent animal production responses to RUP supplementation. Only 17% of the studies reported greater milk yield by cows fed diets of greater RUP concentration. Of these, cows fed fish meal or treated soybean meal showed the most positive milk yield response. Although it is clear that varying the intake of readily fermentable carbohydrates affects the supply of protein to the small intestine, little research has been done that has addressed the relationship of dietary concentration of RUP with that of different NFC sources. Microbial CP yield is influenced by carbohydrate source, nitrogen source, rate of carbohydrate fermentation, bacterial growth rate, dilution rate and pH (Van Kessel and Russell, 1995). Varga et al. (1988) reported a decrease in microbial growth and depressed fiber and protein digestibilities in vitro with substrates having NSC:RDP ratios greater than 6.0. Supplying more microbial crude protein to the small intestine may decrease the need to supplement a diet with additional RUP. If NFC sources differ in their support of microbial yield, they may need to be complemented with different amounts of RUP to optimize nutrient supply to the cow. Companion studies that specifically evaluated the effect of NFC type and RUP supplementation were carried out by Broderick et al. (2002b). They fed 48 multiparous, lactating Holstein cows grouped into six blocks based on covariate protein yield (Trial 1) and six multiparous, lactating Holstein cows fitted with ruminal cannulae randomly assigned to a 6 x 6 Latin square design. The diets included one of three carbohydrate sources (high-moisture ear corn, HMEC; cracked shelled corn, CSC; and a 50:50 mixture of high-moisture ear corn plus dried citrus pulp, HCP) fed with or without ESBM. All diets were fed as TMR containing alfalfa silage at 50% of DM and ryegrass

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30 silage at 10% of DM. All diets contained 26.2 to 29.0% of DM as NDF and 38.2 to 43.7% of DM as total NFC. Expeller soybean meal replaced urea to supply the ruminally undegradable protein. The CP was at least 3% greater for each of the ESBM supplemented diets (18.6 to 19.0% of DM) as compared to the diets without ESBM (22.1 to 22.7% of DM). The HCP diets contained 4.9 and 5.3% sugars and the corn diets ranged from 2.7 to 3.5% sugars (DM basis). Starch ranged from 23.4 to 31.0% of DM for the corn diets compared to 20.0 and 17.1% of DM for the HCP diets. The described orthogonal contrasts compared ESBM vs. no supplement, HMEC vs. CSC, HMEC vs. HCP, CSC vs. HCP, and ESBM on HMEC and CSC vs. ESBM on HCP. In trial 1, DMI, yields of milk, 3.5% FCM, fat and protein and concentrations of MUN and plasma urea N (PUN) were all greater for the diets containing ESBM. Cows fed HMEC and CSC consumed more DM than cows fed HCP (P = 0.08 and P = 0.02, respectively) (Table 2-2). Milk and 3.5% FCM yields were both greater for the cows fed the two corn diets as compared to the diet containing citrus pulp (P = 0.01 for milk yield, HMEC vs. HCP and P = 0.02 for milk yield, CSC vs. HCP) (Table 2-2). Milk components followed suit, with cows consuming the HMEC and CSC having greater yields of milk fat (P = 0.01 for fat, HMEC vs. HCP, P = 0.08, CSC vs. HCP) and protein (P < 0.01 for protein, HMEC and CSC vs. HCP) as compared to those fed HCP. Carbohydrate source did not affect MUN and PUN concentrations. Plasma glucose was only greater for the cows consuming CSC compared to HCP (P = 0.01) (Table 2-2). In the second study cows were in late lactation and ruminal effects of diets were the focus. Ruminal pH and NH 3 -N concentration were greater for the cows fed the +ESBM diets (P = 0.03 and P<0.01, respectively) (Table 2-1). Molar proportions of acetate and

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31 butyrate were decreased for cows not supplemented with +ESBM (P = 0.07 and P = 0.01, respectively). Ruminal fluid pH was less acidic in cows consuming the CSC diets compared to those fed the HMEC or HCP diets (P = 0.04 and P = 0.03, respectively); however, there was little variation with average pH ranging from 6.10 to 6.24. Ruminal NH 3 -N was also greatest for cows fed CSC as compared to those fed HMEC and HCP (P < 0.01 and P = 0.04, respectively). Differences (P < 0.10) in the molar proportions of acetate were not detected in this study for the contrasts for carbohydrate source. Molar proportions of propionate were greatest for HMEC followed by CSC and then HCP (P = 0.03 for HMEC vs. CSC, P<0.01 for HMEC vs. HCP, and P = 0.04 for CSC vs. HCP). Molar proportions of butyrate were smallest from cows fed HMEC intermediate for cows fed CSC and greatest for cows fed HCP (P = 0.03 for HMEC vs. CSC, P<0.01 for HMEC vs. HCP, and P<0.01 for CSC vs. HCP). Acetate to propionate ratio was greatest for the HCP diets (3.42 and 3.45, for -ESBM and +ESBM, respectively) followed by CSC (3.25 and 3.30, for -ESBM and +ESBM, respectively) and HMEC (3.03 and 3.17, for -ESBM and +ESBM, respectively) (P = 0.08 for HMEC vs. CSC, P<0.01 for HMEC vs. HCP, and P = 0.10 for CSC vs. HCP) which expectedly followed the inverse of the propionate values. Based on their results, Broderick et al. (2002b) concluded that the NH 3 and VFA patterns suggested that the carbohydrate fermentation decreased in the order of HMEC > CSC > HCP, proposing that site of digestion may have played a role. In this study, the diet with dried citrus pulp was unable to support the production achieved by the two corn (starch) diets. While effects of ESBM were detected in this study, concentration of total

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32 CP differed in the no supplement vs. the ESBM supplemented diets and this may have affected production. In a study similar to that of Broderick et al. (2002b), Solomon et al. (2000) fed twenty lactating Holstein cows diets of high starch or high pectin with (average of 6.0% of DM as ether extract) or without (average of 3.3% of DM as ether extract) the addition of full fat extruded soybeans. The high starch was achieved by feeding elevated amounts of corn grain and the high pectin by increasing the amount of dry citrus pulp pellets fed. Diets contained similar concentrations of CP, NDF, and total NSC. Dry matter intake was greater for the cows fed high starch (P < 0.01) and the extruded soybeans (P < 0.05) (Table 2-2). Milk yield was greater for the extruded soybean diets compared to those without the beans (P < 0.01). Milk protein concentration was greater for cows consuming more starch (P < 0.01) without the extruded soybeans (P < 0.01). Milk fat yield was greater for cows consuming the extruded soybean diets (P < 0.01) (Table 2-2). Elevated MUN concentrations were detected with the addition of extruded soybeans to the diets (P < 0.01) (Table 2-2). With animal by-products as the RUP source, Mansfield et al. (1994) compared the animal response to supplementation with starch from corn or pectin and sugars from sugar beet pulp. Forty-six Holstein cows were assigned one of four dietary treatments comparing corn and dried sugar beet pulp with either soybean meal (more RDP) or animal by-products (more RUP from meat and bone meal, feather meal, and blood meal) in a randomized complete block design, with a 2 x 2 factorial arrangement of treatments. All diets contained alfalfa pellets, alfalfa hay, corn silage, and concentrate. Beet pulp replaced about half of the corn (15% of DM) to achieve the two carbohydrate treatments.

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33 Significance was declared at P < 0.05. Dry matter intake (kg/d and % of BW) was greater for cows fed corn than for those consuming the beet pulp diet (3.97 vs. 3.69% of BW) (Table 2-2). Milk yield and 3.5% FCM were not affected by dietary treatment. Milk fat concentration was greater for the cows fed the beet pulp (3.82 vs. 3.64%) but this did not translate into an increased milk fat yield (Table 2-2). Milk protein percentage (3.01 vs. 2.90%) and yield (Table 2-2) were decreased for the cows fed the beet pulp diet compared to the corn diet. Feed efficiency (3.5% FCM/DMI, kg/kg) was greater for the cows consuming beet pulp as compared to those consuming corn (1.67 vs. 1.55). Milk protein concentration was greater for the cows fed the soybean meal diet as compared to the RUP animal by-product diet (3.00 vs. 2.91%, respectively). Dry matter intake and feed efficiency were not affected by protein type. Feeding a commercial sugar product and two protein sources, McCormick et al. (2001) evaluated milk production and composition response. Thirty-two multiparous Holstein cows were fed the following diets; solvent SBM (SSBM), SSBM plus 5% brown sugar food product, ESBM, or ESBM plus 5% brown sugar food product. All diets contained ryegrass, ground corn and a mineral mix. Intake of DM was not affected by protein source, sugar, or the interaction of the two. While not statistically significant (P = 0.15 for the protein x sugar interaction), milk yield numerically increased with the addition of sugars to the SSBM diet and decreased with the addition of sugars to the ESBM diet (Table 2-2). Milk fat percentage was numerically greater for the ESBM diets compared to the SSBM (3.39 and 3.53 vs. 3.24 and 3.25%, respectively, P = 0.13). Yields of 3.5% fat-corrected milk, fat and protein were not affected by dietary treatment.

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34 Plasma urea N concentration was greater for cows fed the sugar supplemented diets (P = 0.01) (Table 2-2). Although the information is limited, it appears that NFC source together with RUP supplementation have the potential to change ruminal fermentation characteristics, nutrient supply and consequently production response. More studies that feed various NFC types and different ruminal degradabilities of protein are needed to gain a comprehensive understanding of their effects on VFA, ruminal pH, NH 3 -N, blood metabolites, milk production and milk composition.

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35 Table 2-1. The effects of NFC source and/or RDP/RUP supplementation on ruminal characteristics. Studies are listed in alphabetical order. Reference VFA, Acetate, Propionate, Butyrate, Ruminal NH 3 -N, and Treatment mM ------------mol/100 mol------------pH mg/dl Ariza et al. (2001), continuous culture Citrus pulp 104 68.9 16.7 11.4 --9.30 Hominy feed 101 62.6 22.7 11.0 --14.2 Broderick et al. (2002a), 8 cannulated cows 0.0% sucrose and 7.5% corn starch 106 60.9 20.2 14.3 6.19 6.93 2.5% sucrose and 5.0% corn starch 107 60.8 21.1 13.1 6.16 6.87 5.0% sucrose and 2.5% corn starch 112 60.1 21.4 13.5 6.19 6.21 7.5% sucrose and 0.0% corn starch 104 60.4 22.0 14.0 6.21 5.75 Broderick et al. (2002b), 6 cannulated cows High-moisture ear corn (1) 103 62.7 20.8 11.4 6.10 12.8 Cracked shelled corn (2) 102 63.4 19.7 11.7 6.17 18.5 High-moisture ear corn + dried citrus pulp (3) 107 63.7 18.7 13.0 6.12 15.2 1 + expeller soybean meal 101 63.8 20.3 11.0 6.17 18.5 2 + expeller soybean meal 107 63.9 19.4 11.6 6.24 20.2 3 + expeller soybean meal 108 64.3 18.7 12.3 6.15 18.9 Broderick and Radloff (2002), 8 cannulated cows 0% dried molasses and 29% high moisture corn 129 62.2 22.0 11.5 5.81 11.3 4% dried molasses and 25% high moisture corn 129 63.6 20.8 11.3 5.88 9.12 8% dried molasses and 21% high moisture corn 136 62.0 21.9 11.9 5.79 10.7 12% dried molasses and 17% high moisture corn 132 64.1 19.8 12.0 5.91 10.7 Chester-Jones et al. (1991), in vitro Soybean meal (SBM) + 0% beet pulp 134 41.3 40.8 12.6 ----SBM + 15% beet pulp 130 45.0 42.3 8.80 ----SBM + 30% beet pulp 123 47.2 40.8 7.80 ----Alcohol treated, defatted soybean flakes (ATSBF) + 0% beet pulp 137 42.4 40.3 12.6 ----ATSBF + 15% beet pulp 127 45.9 42.4 7.30 ----ATSBF + 30% beet pulp 122 47.0 43.9 5.80 ----

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36 Table 2-1. Continued VFA, Acetate, Propionate, Butyrate, Ruminal NH 3 -N, Reference mM -------------mol/100 mol------------pH mg/dl Heldt et al. (1999), 20 cannulated steers Low RDP (0.031% BW/d) Control --76.1 13.3 9.0 6.40 0.13 Starch --70.3 17.1 10.0 6.36 0.35 Glucose --59.3 15.5 18.6 6.28 0.27 Fructose --58.8 13.5 19.7 6.36 0.49 Sucrose --56.3 15.5 20.9 6.23 0.28 High RDP (0.122% BW/d) Control --73.5 14.0 10.6 6.56 0.43 Starch --69.5 16.4 10.3 6.13 3.39 Glucose --61.5 14.1 17.5 6.16 4.19 Fructose --59.8 14.2 18.9 6.29 3.99 Sucrose --59.7 14.4 19.5 6.22 2.63 Huhtanen (1988), 4 cannulated bulls Barley 98.1 65.2 15.5 16.1 6.33 5.78 Barley + molasses 99.7 62.0 17.1 17.9 6.21 10.0 Beet pulp 100.5 67.6 17.5 12.8 6.40 6.19 Beet pulp + molasses 93.0 65.5 18.5 13.7 6.45 6.20 Khalili and Huhtanen (1991), 4 cannulated bulls Control (starch) 105 63.6 17.8 14.9 6.28 17.6 Sucrose (1 kg/d) 104 58.9 16.5 19.7 6.03 9.90 Leiva et al. (2000), 11 cannulated cows Citrus pulp diet 116 67.7 20.8 11.5 6.19 --Hominy diet 106 67.4 21.4 11.2 6.24 --Maiga et al. (1995), 10 cannulated cows Control 99.5 60.1 23.4 12.8 6.71 14.5 Fat (2% tallow) 86.6 61.1 22.6 12.5 6.82 12.8 Molasses + fat 96.8 60.8 22.9 13.2 6.68 11.7 Dried whey + fat 88.9 61.4 22.4 12.9 6.85 10.5 Mansfield et al. (1994), Continuous culture Main Effects Corn 113 58.7 21.7 15.3 --21.0 Beet pulp 110 61.6 20.5 14.0 --17.9 Soybean meal 112 60.5 21.1 14.2 --21.8 Animal by-product 110 59.8 21.1 15.1 --17.0

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37 Table 2-1. Continued VFA, Acetate, Propionate, Butyrate, Ruminal NH 3 -N, Reference mM -------------mol/100 mol------------pH mg/dl Moloney et al. (1994), 6 cannulated steers Barley 71.2 66.5 15.8 14.0 6.94 9.26 Molasses 71.7 58.4 16.6 23.0 6.86 5.63 Petit and Veira (1994), 6 cannulated steers Silage alone 100 70.8 17.0 8.69 6.59 10.23 7.5% molasses (mol) 103 71.2 17.1 8.88 6.52 6.88 silage + 15% mol 101 70.8 17.5 9.13 6.50 5.93 7.5% canola meal (cm) 102 71.6 17.0 8.48 6.47 9.59 5.5% cm and 7.5% mol 107 71.5 16.8 8.94 6.50 7.74 3.6% cm and 15% mol 103 70.7 17.5 9.17 6.47 7.54 15% cm 104 70.8 17.5 8.43 6.47 12.16 Piwonka et al. (1994), 6 cannulated heifers Control 82.4 70.0 16.7 9.6 --11.9 Dextrose (5.6% of DM) 91.2 68.9 18.1 9.9 --11.7 Medium concentrate (barley) 90.5 68.7 16.7 11.1 --9.8 Ben-Ghedalia et al. (1989), cannulated rams 16.3% dried citrus pulp 82.4 65.0 17.6 14.3 6.18 --67.5% dried citrus pulp 74.4 69.1 14.4 14.2 6.42 --Kasperowicz (1994), in vitro --------------mM/100 ml-------------Sugar beet pectin P. ruminicola 3.64 1.73 --------Sugar beet pectin L. multiparous 1.76 1.76 --------Sugar beet pectin B. fibrisolvens 0.97 0.74 --------Sugar beet pectin mixed culture 4.10 2.74 1.25 0.15 ----Citrus pectin P. ruminicola 5.19 2.63 --------Citrus pectin L. multiparous 2.04 2.71 --------Citrus pectin B. fibrisolvens 1.82 1.47 --------Citrus pectin mixed culture 4.26 3.08 1.05 0.12 ----

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38 Table 2-1. Continued Reference VFA Acetate Propionate Butyrate Ruminal NH 3 -N, and Treatment --------------------------mM------------------------pH mg/dl Martin et al. (2000), in vitro fermentation No substrate Sugar + malate (0.0 g/L) 39.8 31.0 4.30 3.1 6.57 --Sugar + malate (2.25 g/L) 66.8 49.3 11.1 5.1 6.40 --Sugar + malate (3.25 g/L) 64.1 46.3 11.4 5.0 6.40 --Ground corn Sugar + malate (0.0 g/L) 86.8 53.0 13.1 18.8 6.00 --Sugar + malate (2.25 g/L) 102 62.2 19.7 17.6 5.90 --Sugar + malate (3.25 g/L) 101 65.2 18.9 15.0 5.80 --Soluble starch Sugar + malate (0.0 g/L) 89.5 53.6 13.2 20.4 5.92 --Sugar + malate (2.25 g/L) 101 62.5 17.5 19.1 5.96 --Sugar + malate (3.25 g/L) 103 64.5 18.1 18.1 5.96 --McCormick et al. (2001), in vitro fermentation Solvent soybean meal 33.4 20.2 8.21 3.33 6.67 9.36 Expeller soybean meal 29.1 18.6 7.27 2.97 6.79 8.52 Control 32.8 18.3 7.89 3.63 6.77 9.13 2.5% lactose 31.3 20.5 7.45 3.22 6.78 9.23 5.0% lactose 30.3 19.0 7.88 2.95 6.78 9.09 2.5% sucrose 31.6 19.6 8.63 2.80 6.78 8.76 5.0% sucrose 30.3 19.4 6.83 3.17 6.78 8.45 Sannes et al. (2002), 4 cannulated cows Starch 131 85.3 26.3 16.2 --6.89 Sucrose 123 77.8 27.1 15.5 --5.45 Strobel and Russell (1986) In vitro, pH 6.7 Starch --5.1 2.9 0.8 6.7 --Sucrose --4.7 2.1 1.1 6.7 --Pectin --10.1 1.3 0.2 6.7 --In vitro, pH 6.0 Starch --2.7 1.1 0.7 5.8 --Sucrose --1.7 1.1 0.7 5.5 --Pectin --5.0 0.7 0.3 5.8 --

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39 Table 2-2. Effects of NFC source and/or RUP/RDP supplementation on intake, plasma measures, and milk production and composition. Studies are listed in alphabetical order. Reference DMI, Milk, Fat, Protein, MUN, Glucose, Insulin, PUN, and Treatment ------------------kg/d ----------------mg/dl mg/dl ng/ml mg/dl Broderick et al. (2002a), 48 lactating cows 0.0% sucrose 7.5% corn starch 24.5 38.9 1.47 1.24 --------2.5% sucrose 5.0% corn starch 25.6 40.4 1.53 1.28 --------5.0% sucrose 2.5% cornstarch 26.0 40.0 1.65 1.29 --------7.5% sucrose 0.0% corn starch 26.0 39.4 1.62 1.28 --------Broderick et al. (2002b), 48 lactating cows High-moisture ear corn (1) 20.0 34.5 1.18 1.01 12.3 48.5 --14.0 Cracked shelled corn (2) 20.9 33.6 1.11 1.00 11.8 52.0 --13.0 High-moisture ear corn + dried citrus pulp (3) 19.2 29.9 0.98 0.80 11.8 47.0 --13.5 1 + ESBM 21.8 35.8 1.30 1.06 19.8 50.6 --20.1 2 + ESBM 21.9 36.5 1.26 1.11 18.9 50.3 --18.8 3 + ESBM 20.2 34.2 1.15 0.96 19.1 48.3 --19.3 Broderick and Radloff (2002), 48 lactating cows 0.0% dried molasses and 29.0% high moisture corn 25.1 38.0 1.54 1.19 15.3 ------4.0% dried molasses and 25.0% high moisture corn 25.8 37.5 1.59 1.14 14.4 ------8.0% dried molasses and 21.0% high moisture corn 26.2 38.9 1.63 1.23 15.0 ------12.0% dried molasses and 17.0% high moisture corn 26.0 36.7 1.47 1.09 14.7 ------Fegeros et al. (1995), 6 lactating ewes Control (corn, barley, and wheat middlings) 1.14 0.82 0.06 0.04 --------Dried citrus pulp 1.44 0.78 0.06 0.04 --------

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40 Table 2-2. Continued Reference DMI, Milk, Fat, Protein, MUN, Glucose, Insulin, PUN, and Treatment --------------------kg/d ----------------mg/dl mg/dl ng/ml mg/dl Friggens et al. (1995), 18 lactating cows Beet pulp --14.3 0.60 0.48 --------Beet pulp : Grain (50:50) --14.9 0.57 0.51 --------Grain (barley and corn) --14.5 0.58 0.50 --------Lees et al. (1990), 28 lactating cows Beet pulp low CP 14.4 20.6 0.80 0.60 --------Beet pulp high CP 14.6 23.3 0.95 0.70 --------Maize low CP 12.0 21.7 0.62 0.64 --------Maize high CP 12.4 24.5 0.65 0.74 --------Leiva et al. (2000), 11 lactating cows Citrus pulp diet 20.9 31.3 1.11 0.85 --------Hominy diet 21.4 32.8 1.12 0.93 --------Maiga et al. (1995), 40 lactating cows Control 23.1 31.9 1.09 0.94 --------Fat (2% tallow) 24.3 33.7 1.22 1.01 --------Molasses + fat 24.5 33.7 1.15 0.97 --------Dried whey + fat 24.5 34.0 1.17 0.98 --------Mansfield et al. (1994), 46 lactating cows Main effect means Corn 21.5 32.2 1.18 0.97 --------Beet pulp 20.3 31.9 1.21 0.92 --------Soybean meal 21.1 31.9 1.21 0.96 --------Animal by-product 20.7 32.1 1.19 0.93 --------McCormick et al. (2001), 32 lactating cows 0% sucrose + solvent soybean meal 22.8 39.3 1.22 1.10 21.5 ----18.3 5% sucrose + solvent soybean meal 23.1 39.8 1.26 1.14 21.2 ----19.3 0% sucrose + expeller soybean meal 22.8 39.9 1.34 1.18 19.8 ----16.7 5% sucrose + expeller soybean meal 22.6 37.5 1.33 1.11 21.3 ----19.4

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41 Table 2-2. Continued Reference DMI, Milk, Fat, Protein, MUN, Glucose, Insulin, PUN, and Treatment ---------------------kg/d ---------------mg/dl mg/dl ng/ml mg/dl Nombekela and Murphy (1995), 24 lactating cows Control (starch) 19.0 28.4 0.96 0.96 --------Sucrose 19.1 29.3 0.97 0.95 --------Ordway et al. (2002), 34 transitioning cows prepartum Ground corn 16.0 --------66.3 0.64 --2.7% sucrose 16.5 --------69.3 0.76 --postpartum Ground corn 22.1 45.8 ------55.8 0.23 --2.7% sucrose 22.7 45.6 ------56.7 0.25 --Sannes et al. (2002), 16 lactating cows Starch 25.7 34.3 1.33 1.07 14.3 ----13.9 Sucrose 25.5 33.2 1.27 1.03 13.3 ----13.8 Solomon et al. (2000), 20 lactating cows High starch 20.0 35.5 1.18 1.05 13.6 ------High starch + extruded soybeans 22.0 38.3 1.26 1.09 15.3 ------High pectin 20.3 34.6 1.16 1.01 13.7 ------High pectin + extruded soybeans 20.8 38.2 1.26 1.07 15.4 ------Valk et al. (1990), 45 lactating cows Beet pulp 1 --25.8 1.07 0.89 --------Maize 1 --28.4 1.11 0.98 --------Beet pulp 2 --30.9 1.29 1.02 --------Maize 2 --31.6 1.17 1.03 --------Beet pulp + Maize 2 --30.8 1.24 1.02 --------Van Horn et al. (1975), 36 lactating cows 43.1% citrus with urea 17.3 16.6 0.69 0.56 --------8.0% citrus with urea 17.5 17.8 0.64 0.60 --------43.1% citrus with soybean meal 20.1 18.3 0.81 0.65 --------8.0% citrus with soybean meal 20.0 19.6 0.67 0.70 --------

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CHAPTER 3 EFFECTS OF NONFIBER CARBOHYDRATE SOURCE AND PROTEIN DEGRADABILITY ON LACTATION PEFORMANCE OF HOLSTEIN COWS Introduction Collectively, carbohydrates make up 65 to 75% of the diets of lactating dairy cattle. Dietary carbohydrate is comprised of fiber (NDF) and nonfiber (NFC) fractions. Nonfiber carbohydrates may provide 30 to 45% of the diet on a dry matter (DM) basis. Although NFC has been represented as a single value for feeds or diets, the type of carbohydrates in this fraction can vary greatly. For example, the NFC in corn grain is mostly starch (65 to 70% of DM), citrus pulp provides sugar (12 to 40% of DM) and neutral detergent-soluble fiber (NDSF) (25 to 44% of DM), and sugar (monoand oligosaccharides) predominates in molasses (Hall, 2002). The dietary complement of NFC has the potential to alter the supply of metabolizable nutrients to the animal because NFC differ in digestion and fermentation characteristics. In vitro fermentation of sucrose, starch, and pectin resulted in different organic acid profiles (Strobel and Russell, 1986), and in maximal microbial protein yields (Hall and Herejk, 1999). Unlike other NFC, maltose and starch may be digested by mammalian enzymes; monosaccharides and the digestion products may be absorbed in the small intestine. Perhaps because of differences in digestion products, the NFC complement of the diet has the potential to alter feed intake, milk production and composition of milk. Dietary inclusion of feeds with greater contents of pectin have increased intake (Valk et al., 1990; Lees et al., 1990; Chester-Jones et al., 1991). Compared to starch, pectin-rich 42

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43 feeds have decreased milk yield (Van Horn et al., 1975; Leiva et al., 2000; Broderick et al., 2002b) and yield and percentage of milk protein (Mansfield et al., 1994; Leiva et al., 2000; Solomon et al., 2000; Broderick et al., 2002b). Milk fat percentage was increased (Van Horn et al., 1975; Lees et al., 1990; Mansfield et al., 1994) or remained unchanged with the feeding of pectin-rich diets (Leiva et al., 2000; Solomon et al., 2000). Supplementation of sugars in place of starchy feeds decreased milk protein percentage (Nombekela and Murphy, 1995) and yield (Sannes et al., 2002). Still other studies reported no difference in intake or production as the dietary NFC profile changed (Fegeros et al., 1995; Malestein et al., 1984). The objective of this study was to evaluate the effects of altering the dietary complement of NFC at two different dietary concentrations of ruminally undegradable protein (RUP) on lactation performance, as well as on blood and ruminal measures. Materials and Methods Cows, Diets, and Facilities Thirty eight multiparous Holstein cows (six ruminally fistulated, 10 cm i.d., Bar Diamond, Inc. Parma, ID) (82 19 days in milk average bodyweight of 614 56 kg) were assigned randomly to a series of dietary treatments in a partially balanced, incomplete Latin square design with three 21-d periods (14 d for acclimation and 7 d for sample collection). In the second period the cows received a 28-d acclimation to diets due to technical difficulties with the feeding system. In the 3 x 2 factorial arrangement of treatments, the three NFC dietary treatments were starch (ST), soluble fiber plus sugar (SF), or sugar (SU), achieved by altering the proportions of ground corn, citrus pulp, liquid molasses, and sucrose included in the diet. Two concentrations of degradable protein were achieved by supplementing with 48% soybean meal (-RUP) or with a

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44 combination of expeller soybean meal (SoyPLUS; West Central Soy, Ralston, IA) and 48% soybean meal (+RUP). All diets were formulated to contain similar basal concentrations of forage (corn silage and sorghum silage), to be isonitrogenous, and to contain similar concentrations of total NFC and NDF (Table 3-1). Analysis of nutrient contents of the total mixed rations (TMR) indicated that percentages of NDF differed by NFC source with SF diets containing more NDF than SU diets (P < 0.01). Percentages of CP in the TMR were greater for cows fed RUP diets as compared to +RUP (P = 0.02) and for cows fed SU diets as compared to those consuming SF (P < 0.05). However, the differences in measured percentages for NDF and CP in the diets were small (Table 3-1), with the average difference from the mean values of 0.33% and 0.85% of diet DM for CP and NDF contents, respectively. The RUP diets differed from each other by an average of 0.57% CP on a DM basis. Cows were fed individually with diets offered in ad libitum amounts twice daily (at 0600 and 1300 h) through Calan gates (American Calan, Northwood, NH). Cows were milked three times each day at 0500, 1300, and 2100 h. The experiment was conducted at the University of Florida Dairy Research Unit, Hague, Florida, from January to March 2002. Cows were housed in an open-sided, free-stall barn bedded with sand and equipped with fans and misters. Animals were maintained under protocols approved by the University of Florida Institutional Animal Care and Use Committee. Sample Collection and Analyses Amounts of diets fed and refused were recorded daily with subsamples of the TMR and orts obtained for each individual cow during the seven day collection phase of each period. Two to three grams of TMR and orts samples were dried in a forced-air oven at 105C until a constant weight was achieved to determine DM content. Daily dry matter

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45 intake (DMI) was calculated for each animal. The remainders of the samples were individually dried at 55C in a forced-air oven and ground to pass the 1-mm screen of a Wiley mill (A.H. Thomas, Philadelphia, PA) prior to compositing. All TMR and ort samples were composited on a DM basis by cow by period. Composited diet samples were analyzed for DM (105C for 8 h) and organic matter (OM) (512C for 8 h). Neutral detergent fiber was measured using heat-stable, -amylase (Goering and Van Soest, 1970; Van Soest et al., 1991) and was not corrected for ash content in order to retain samples for further analysis. Starch, sugar (80% ethanol-soluble carbohydrate), and NDSF contents of the feed and orts were determined as described by Hall et al. (1999). Crude protein (CP) as N x 6.25 was determined by micro-Kjeldahl using an aluminum block digester (Gallaher et. al., 1975) and an autoanalyzer (ALPKEM Corporation, Method Number A303-S071). The CP contents of 80% ethanol-insoluble residue and NDF (NDFCP) were determined by a modification of a Kjeldahl N procedure (AOAC, 1990) in which a digestion mixture of 96% Na 2 SO 4 and 4% Cu 2 SO 4 was used in the digestion and distilled ammonia was recovered in a 4% boric acid solution (Pierce and Haenisch, 1947). Milk weights were recorded for all milkings during the collection period and samples were collected on d 15, 17, and 19 from all three daily milkings. All milk samples were analyzed by Lancaster DHIA Labs (Lancaster, PA). Milk samples were analyzed for fat and protein using mid-infrared technology (Model B-2000, Bentley Instruments, Chaska, MN). Milk urea nitrogen (MUN) was analyzed by an enzymatic and colorimetric method (Model Chemspec 150, Bentley Instruments, Chaska, MN). Somatic cell count (SCC) was measured by laser counting technology (Model

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46 Somacount 500, Bentley Instruments, Chaska, MN). Production of fat (3.5%)and protein-corrected milk (3.5% FPCM) was calculated by the following equation (derived from Tyrrell et al., 1965): 3.5% FPCM kg/d = (12.82 x fat in kg/d) + (7.13 x protein in kg/d) + (0.323 x milk in kg/d). Feed efficiency was calculated as 3.5% FPCM divided by DMI. Efficiency of nitrogen utilization was determined by the following equation: Milk N / Intake N = (milk kg x (milk protein% / 6.38)) / (DMI kg x (diet CP% / 6.25)). The concentration of net energy of lactation per unit of DMI was estimated by the following equation (NRC, 2001) with all milk measures expressed terms of per cow per day: NE L Mcal/kg of DMI = [(0.08 x BW 0.75 kg) + ((0.0929 x milk fat %) +(0.0547 x milk crude protein %) +0.192) x milk kg)] / DMI kg. For the purpose of comparisons among treatments, it was assumed that energy required for growth, reproduction, and repletion of reserves were minor contributors to energy demands of the cattle on this study. Blood samples (~10 ml) were collected from individual cows on d 15 and 17 of each period by coccygeal venipuncture into Vacutainer tubes (Becton Dickinson, Franklin Lakes, NJ) containing sodium heparin, which were immediately placed on ice. Duplicate samples were transferred into capillary tubes and centrifuged in a micro-capillary centrifuge (I.E.C. MB Centrifuge) to determine hematocrit and plasma protein.

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47 Hematocrit values were measured on whole blood with a Damon micro-capillary reader (I.E.C. Cat. No 2201). Plasma protein content was measured using a Schuco refractometer (Model 5711-2020). Samples were centrifuged at 1916 x g for 30 min at 5C to separate plasma, which was transferred to vials and frozen at -20C until analysis. An autoanalyzer (Technicon Instruments Corp., Chauncey, NY) was used to measure plasma urea N (PUN) (a modification of Marsh et al., 1965 as described in Bran and Luebbe Industrial Method #339-01) and plasma glucose (a modification of Gouchman and Schmitz, 1972 as described in Bran and Luebbe Industrial Method #339-19). Plasma insulin was analyzed with a double antibody radioimmunoassay procedure described by Soeldner and Sloane (1965) and modified by Malven et al. (1987). A Packard auto gamma counter (model B-5005) measured bound radioactivity in tubes. In Situ Ruminal Incubations Extent of DM and NDF disappearance of sorghum silage was measured on d 16, 17, and 18 of each period by the dacron bag technique (Nocek, 1988) using the ruminally cannulated cows. At the beginning of the study approximately 25 kg of sorghum silage was collected and dried at 55C for 48 h, and ground to pass a 2-mm screen (Wiley mill, A.H. Thomas, Philadelphia, PA). Approximately 5.0 g (air dry) was weighed into pre-weighed polyester bags (10 x 20 cm) with an average pore size of 53 10 m (Bar Diamond, Inc., Parma, ID). Duplicate bags were inserted into a nylon mesh bag, which was inserted into the rumen via the rumen cannula, at intervals of 0, 6, 12, 18, 24, 30, and 48 h. All bags were removed simultaneously. The mesh bags were weighted (~ 1kg) to keep them submerged in the rumen contents. Following removal, bags were submerged in cold water and rinsed continuously until the water was clear. Bags were then rinsed in a washing machine on the delicate/cold cycle (Kenmore 70 series, Heavy Duty, Super

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48 Capacity, Sears, Roebuck and Co., IL). Bags were dried in a forced-air oven at 55C for 48 h, and weighed to determine DM residue. The residue was analyzed for NDF (Goering and Van Soest, 1970; Van Soest et al., 1991) using heat-stable, -amylase and corrected for ash content. The potentially digestible fraction and rate of disappearance of the sorghum silage could not be determined because the curve describing sample disappearance did not plateau by the end of the incubation period (48 h). Consequently, bags representing treatments were compared within hour. Ruminal Fluid Sampling and Analysis Ruminal fluid samples were collected via ruminal cannulae from the six ruminally cannulated cows on d 20 of each period. Starting prior to feeding and continuing hourly for the next 13 h, ruminal fluid (~500 mL) was collected from the cranial, ventral and caudal areas of the rumen. Samples were capped, inverted to mix, and pH measured immediately with an electronic pH meter (Fisher Scientific, Accumet Model 15). For each sample, a subsample of 40 ml was acidified with 1 ml of 50% sulfuric acid and centrifuged at 5400 x g for 20 min. The supernatant was collected and frozen at -20C until analysis for volatile fatty acids (VFA) by gas chromatography (4% carbomax 80/120 BDA column, Supelco Inc., Bellefonte, PA) (Autosystem XL gas chromatograph, Perkin Elmer Inc., Norwalk, CT). For analysis, samples were thawed at room temperature (approximately 23C) and centrifuged at 5000 x g for 30 min and filtered with a high affinity protein syringe-driven filter unit (Millex SLAA025LS, Fisher Scientific, Pittsburg, PA). The gas chromatograph was set to a flow rate of 30 ml/min of N, an injection port temperature of 200C, oven at 190C, and the flame ionizing detector at 450C.

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49 Due to multiple health disorders not related to the study, one of the cannulated cows was removed from the study in the third period and was not used for any sampling in that period. Therefore, data for ruminal measures during the third period are for five cows. Statistical Analysis In all analyses, terms including cow were treated as random variables. Average values per cow per period for TMR composition, feed intake, milk production, milk composition, plasma urea nitrogen, plasma glucose, plasma insulin, and in situ substrate disappearance by hour were analyzed by the MIXED procedure of SAS (1996). Data were analyzed according to the model: Y ijkl = + C i + P j + N k + R l + NR kl + ijkl = overall mean, C i = effect of cow (i = 1, 2, ), P j = effect of period (j = 1, 2, 3), N k = effect of NFC treatment (k = ST, SF, SU), R l = effect of RUP treatment (l = +RUP, -RUP), NR kl = effect of interaction of NFC with RUP treatments, and ijkl = residual error. Although reported as pH, ruminal pH was analyzed as hydrogen ion concentration (Murphy, 1982). Ruminal hydrogen ion concentration and VFA data were analyzed as repeated measures by the MIXED procedure of SAS (1996) with the model: Y ijklm = + C i (P j N k R l ) + P j + N k + R l + NR kl + H m + PH jm + RH lm + NH km + NRH klm + ijklm = overall mean,

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50 C i (P j N k R l ) = effect of cow within period and diet (i = 1, 2, 3, 4, 5, 6), P j = effect of period (j = 1, 2, 3), N k = effect of NFC treatment (k = ST, SF, SU), R l = effect of RUP treatment (l = +RUP, -RUP), NR kl = effect of interaction of NFC with RUP treatments, H m = sampling hour (0, 1), PH jm = interaction of period and sampling hour, RH lm = interaction of RUP treatment and hour, NHkm= interaction of NFC and hour, NRH klm = interaction of NFC, RUP and hour, ijklm = residual error. Results are reported as least squares means. The orthogonal contrasts performed were ST vs. SF+SU and SF vs. SU for effect of NFC and interaction of NFC and RUP. Mean separation was performed using the Tukey-Kramer adjustment. Significance was declared at P < 0.05, and tendency at 0.05 < P < 0.10. Results and Discussion Intake and Lactation Performance The NFC and RUP treatments and their interaction affected various measures of performance including DMI and production and composition of milk. Dry matter intake differed by NFC treatment, with cows consuming more on SU than on SF, and cows consuming ST tending to have greater intakes than those receiving the other NFC diets (Table 3-2). Definitive information is lacking regarding the impact of changing the complement of NFC on DMI. Substitution of sugars for starch has increased (Broderick et al., 2002a) or did not change (Nombekela and Murphy, 1995; Ordway et al., 2002)

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51 intake in dairy cattle. Increases in dietary concentrations of NDSF at the expense of starch increased (Lee et al., 1990; Chester-Jones et al., 1991), decreased (Valk et al., 1990; Broderick et al., 2002b), or did not affect (Van Horn et al., 1975; Leiva et al., 2000) DMI. Changes in passage rate (Piwonka et al., 1994) or fiber digestibility (Heldt et al., 1999) with varying NFC source may offer partial answer as to why the changes occur. In the present study, intake was unaffected by protein degradability. As designed, intake of sugars, starch, and NDSF changed with varying NFC treatment. Cows fed treatments ST, SF, and SU had the greatest intakes of starch, NDSF, and sugars, respectively (Table 3-2). Cows tended to consume more starch and consumed more NDSF when fed SF diets than SU diets. Cows consuming the ST treatment gave the smallest sugar and NDSF intakes compared to the other NFC treatments. Intake of NDF did not differ by treatment. However, there were some unexpected differences in intakes of total NFC, ash, and CP. Cows consuming ST and SU diets had greater intakes of total NFC as compared to those consuming SF diets. Intakes of ash were about 0.2 kg/d greater for cows consuming SU diets as compared to those consuming SF diets. Protein intake differed by RUP treatment, with cows offered RUP diets consuming more CP, which may be due in part to the reduced CP% of DM of the +RUP diets. Animals offered SU consumed more CP and NDFCP than those receiving SF. Diets were formulated to be isonitrogenous and to contain a greater concentration of CP (~17%) than measured (Table 3-1). The differences in dietary CP content could relate to undetected changes in forage or concentrate ingredients. Alternatively, the mineral mix provided 0.9% of diet DM as urea; hydrolysis of the urea and its release as ammonia as it was blended with the silage might result in less than

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52 expected measured CP concentrations. The MUN values observed for the cows suggest that degradable protein was not limiting in the diets (Table 3-3). Although replacing starch with sugars has sometimes increased intake, a milk production response has not always followed (Broderick et al., 2002a; Broderick and Radloff, 2002). In contrast, an increase in production with sugar supplementation without a concomitant increase in intake has been reported (McCormick et al., 2001). More consistent patterns of decreased milk yield response with replacing starch sources with sources of NDSF have been reported (Van Horn et al., 1975; Leiva et al., 2000; Broderick et al., 2002b). Milk composition response has varied, with protein usually decreasing with the inclusion of sugars (Nombekela and Murphy; 1995; Maiga et al., 1995; Sannes et al., 2002) and pectin-rich feeds (Mansfield et al., 1994; Leiva et al., 2000; Solomon et al., 2000; Broderick et al., 2002b). The milk fat response also has varied with NFC source, with pectin-rich diets (Lees et al., 1990; Mansfield et al., 1994) and sugars (Broderick et al., 2002a) increasing fat concentrations or amounts. Studies also have reported no effect on milk fat when feeding pectin-rich diets compared to those high in starch (Leiva et al., 2000; Solomon et al., 2000). In the present study, 3.5% FPCM tended to differ among NFC with cows consuming SU having greater yields as compared to SF (Table 3-3). There was a numerical decrease in 3.5% FPCM yield for ST and an increase for SU and SF with the +RUP treatment, which gave rise to a significant NFC x RUP interaction. Milk fat yield was not affected by treatment. Milk protein yield differed by NFC with cows fed ST having greater protein yields than SU and SF. This is consistent with Broderick et al. (2002b) where cows fed high moisture or cracked corn diets produced more milk protein

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53 than those consuming diets with dried citrus pulp. Cows fed SU diets tended to produce greater amounts of milk protein as compared to those fed SF. Milk urea N concentration was greater in cows fed ST than SU and SF. There was also a tendency for cows fed RUP to have greater MUN concentrations. The estimated net energy of lactation (NE L mcal/kg) of the diets differed for the interaction of NFC x RUP and tended to differ by NFC source (Table 3-2). The NE L content of ST tended to be less than for SF and SU. Indirectly, this is consistent with the work of Ariza et al., (2001) that reported increased efficiency of microbial N yield per kg of OM truly fermented on a substrate containing more sugar and NDSF than on one containing more starch. Dietary NE L was decreased for ST with the addition of +RUP, while SU and SF had an increased NE L when +RUP was fed. Little work has been done on NE L determination of non-starchy concentrate or by-product feeds (H. Tyrrell, personal communication). Feed efficiency differed for the interaction of NFC x RUP. Feed efficiency of cows fed +RUP diets decreased when fed ST, but increased when fed SU or SF diets (Table 3-3). This suggests that the cows fed the ST diet did not require additional RUP for milk production, which could have been the case if there was a greater ruminal yield of microbial protein in cows consuming ST or if other nutrients became limiting before protein. Nitrogen efficiency (Milk N/Feed N) tended to vary by NFC source with greater values for cows fed the ST diets as compared to those fed SF and SU diets. The greater microbial protein yields previously reported for starch as compared to sucrose (in vivo; Sannes et al., 2002) and to sucrose and citrus pectin (in vitro; Hall and Herejk, 2001)

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54 could partially explain the greater protein yields and differences for feed and N efficiencies for ST in this study. Plasma and Ruminal Measures Plasma protein concentration and hematocrit (Table 3-3) were not affected by treatment and were not used to adjust the concentrations of metabolites in the blood. Plasma glucose and insulin concentrations were greater for cows fed SU as compared to SF. Increases in blood glucose have been noted previously in dry cows with the inclusion of 2.7% sucrose in the diets (Ordway et al., 2002). Plasma urea N followed the same pattern as MUN increasing with RUP as compared to +RUP, and with ST greater than SU and SF. In the current study, mean ruminal fluid pH differed little by dietary treatment. For +RUP as compared to RUP, the pH was numerically greater for SU, and smaller for ST and SF, with SURUP showing a visibly decreased pH over time than the other treatments (Table 3-3, Figure 3-1). Ruminal pH was affected by sampling hour (P < 0.01) and NFC x hour (P = 0.01) (Figure 3-1). Although pH differences were not detected in the current study (Table 3-4), several studies have shown decreased ruminal pH with the addition of sugars to the diet (Khalili and Huhtanen, 1991; Moloney et al., 1994; Maiga et al., 1995; Martin et al., 2000). In contrast, Heldt et al. (1999) found that feeding starch decreased pH more than feeding glucose, fructose and sucrose. Several effects of NFC source and RUP supplementation, as well as hour of sampling, were detected for ruminal measures. Total VFA concentrations changed over time (P < 0.01) (Figure 3-2), but were not affected by dietary treatment (Table 3-4). Similarly, a number of studies have not detected a change in total ruminal VFA concentration with varying NFC complement (Mansfield et al., 1994; Piwonka et al.,

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55 1994; Leiva et al., 2000; Sannes et al., 2002). Ruminal acetate molar percentage changed over time (P < 0.01) and tended to differ by NFC x hour (P = 0.07). The mean molar percentage of acetate tended to be greater in the ruminal fluid of cows fed SF diets compared to that of cows fed SU diets. This change in acetate was not associated with an increased milk fat yield for cows consuming SF diets. Propionate molar percentage differed only by time of sampling (P < 0.01). These findings differ from those of an in vitro fermentation study that reported increased propionate yields from starch fermentation as compared to that of citrus pectin fermentation, but agrees with their findings of increased acetate concentrations from citrus pectin as compared to sucrose (Strobel and Russell, 1986). Molar percentage of butyrate differed by NFC and hour (P < 0.01) with SU and SF greater than ST, and SU greater than SF. This is consistent with numerous studies (Strobel and Russell, 1986; Khalili and Huhtanen, 1991; Moloney et al., 1994; Friggens et al., 1998; Heldt et al., 1999; Broderick and Radloff, 2002) where the greatest increase in butyrate was demonstrated with feeding sugars as compared to starch. Butyrate molar percentage was also affected by NFC x hour (P = 0.02), RUP x hour (P = 0.04), and NFC x RUP x hour (P = 0.05). The molar percentage of branch chain VFA (BCVFA) differed among NFC treatments and by sampling hour (P < 0.01) with ST greater than SU and SF, and SF greater than SU. This is consistent with a number of studies that have reported a decrease in BCVFA when replacing corn with sucrose (Broderick and Radloff, 2002; Broderick et al., 2002a; Sannes et al., 2002). In those studies the reported decreases in BCVFA were accompanied by decreases in ruminal NH 3 -N.

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56 The acetate to propionate ratio was greater (acetatepropionate) for +RUP diets and SF diets gave greater values than did SU. Also, SU and SF tended to have greater acetate to propionate ratios than ST. This is a result of the increased acetate molar percent from the SF feeding. These findings are consistent with research that showed that fermentation of pectin, the predominant soluble fiber in citrus pulp, yields considerably more acetate than propionate compared to other NFC (Strobel and Russell, 1986). The proportion of residual DM and NDF in situ differed by NFC source for several of the sampling hours (Table 3-5). In hours 18 through 30 cows consuming ST and SF both had less residual DM and NDF as a percentage of the original substrate than did SU. This result is in contrast to studies where digestibility of NDF increased with sugar supplementation in vivo (Piwonka et al., 1994; Heldt et al., 1999), but in agreement with digestibility increases noted when feeding pectin-rich feeds (Ben-Ghedalia et al., 1989; Van Vuuren et al., 1993b) and decreases in rate of NDF digestion when fermenting glucose, attributed to a proteinaceous inhibitor (Piwonka and Firkins, 1996). In the present study, the low pH noted on SU-RUP may have had a negative effect on ruminal digestion, resulting in SU exhibiting more depressed ruminal digestibilities than the other NFC treatments. Alternatively, the decreased BCVFA noted for SU as compared to other NFC treatments may have made this nutrient limiting for fiber utilizing bacteria, and thus limited their ability to grow and digest fiber. Protein degradation products have been shown to be stimulatory to fibrolytic bacteria (Stewart and Bryant, 1988). In situ disappearance of DM and NDF was also affected by RUP in hours 12 and 24 (and 30 for DM). The RUP diets had a greater percentage of remaining DM and NDF when

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57 compared to the +RUP. Additionally, there were several significant interactions of NFC with RUP in hours 6 through 30. In these sampling hours, less DM and NDF were recovered on +RUP for ST and SU, whereas with SF, more DM and NDF remained on +RUP. This suggests that the supplementation of +RUP had a positive effect on ruminal digestion for the ST and SU diets and negative for SF. If RDP was limiting in the SF+RUP diets NDF digestion may have been reduced, however, such a nutrient limitation does not appear to be supported by the MUN or PUN results. The source of NFC together with sufficiency of RDP has been shown to vary in its effects on digestibility of organic matter and NDF (Heldt et al., 1999). Conclusions Varying dietary NFC source together with degradability of dietary protein altered intake, lactation performance, and blood and ruminal measures in lactating dairy cows. The findings of this study suggest that the lactation performance of dairy cattle may be similar when starch or sugars are the main NFC source, but may be reduced when sugars and soluble fiber, as supplied by citrus pulp, are the main NFC source. This response may be due in part to the decreased intakes of cows consuming SF diets. Despite differences in lactation performance, feed efficiency was similar for the starch-, sugarand pectin-rich diets. That feed efficiency and 3.5% FPCM yields on the sugar and citrus diets improved and those on the starch diets declined with increasing RUP, suggest that differences in metabolizable protein yields as affected by the NFC portion of the diets can be supplemented through modification of the dietary protein component. Curiously, estimates of NE L values of the diets suggest that the diets with the greatest starch contents had relatively lesser energy contents.

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58 Compared to the other NFC treatments, consumption of sugars appeared to modify ruminal protein degradation or metabolism. In this study and other studies cited herein, the greatest molar percentage of butyrate and smallest BCVFA molar percentage or concentration have been reported for cows consuming diets containing sugars. Possible explanations for the decreases in ammonia (from other studies) and BCVFA values noted for molasses and sucrose feeding include: decreased RDP or microbial degradation in the rumen, increased usage of BCVFA and NH 3 -N by sugar-utilizing microbes, or increased rate of passage from the rumen. The decreased in situ disappearance of NDF noted on the sugar-rich diet in this study may be related to competition for BCVFA and NH 3 -N between fiber-utilizing and sugar-utilizing microbes. The potential effect of decreased ruminal pH on fiber digestion relative to other diets only applies to the SU-RUP treatment. That ruminal NDF disappearance increased on the starch and sugar diets and decreased on the citrus diet with the addition of RUP is not so readily explained. There is limited discussion of root causes of non-pH-associated changes in fiber digestion in the literature. This area requires further evaluation. The results of this study indicate that changing dietary NFC together with protein degradability can alter lactation performance, possibly through modification of the metabolizable nutrient supply received by the cow. Further work is needed to determine the optimal concentrations of NFC types, in combination with protein degradability and other dietary components, required to promote efficient lactation performance by dairy cows.

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59 Table 3-1. Ingredient and chemical composition of diets. Ingredient, Diets 1 % of diet DM ST-RUP ST+RUP SF-RUP SF+RUP SU-RUP SU+RUP Corn silage 25.9 25.7 25.6 25.2 26.2 25.9 Sorghum silage 11.9 11.8 11.7 11.6 12.0 11.9 Cottonseed hulls 3.9 3.8 3.9 3.8 3.9 3.9 Whole cottonseed 13.6 13.3 13.6 13.4 13.8 13.5 48% Soybean meal 14.6 5.8 15.8 6.4 16.6 6.7 SoyPLUS 2 --9.7 --10.5 --10.9 Corn meal 20.9 20.7 3.8 3.8 1.9 1.9 Citrus pulp 3.8 3.8 20.7 20.4 9.8 9.7 Molasses --------7.1 7.1 Sucrose --------3.3 3.2 Limestone 1.2 1.3 0.6 0.7 1.1 1.1 Mineral mix 3 4.2 4.2 4.3 4.2 4.3 4.3 Measured component, % of diet DM CP 16.4 15.4 16.3 16.2 17.0 16.5 NDF 39.1 39.6 40.7 40.5 38.5 38.1 NDFCP 3.6 4.0 3.8 4.0 3.8 4.0 Sugar 4.1 4.3 7.6 8.0 13.1 13.5 Starch 23.4 23.6 14.8 15.3 13.4 13.0 NDSF 4 1.9 1.9 5.5 5.3 4.0 3.3 Sum of NFC 5 29.4 29.8 27.8 28.5 30.5 29.8 Ash 6.4 6.3 6.6 6.5 7.0 6.9 1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses + sucrose, -RUP = soybean meal, and +RUP = expeller soybean meal. 2 West Central Soy, Ralston, IA. 3 Mineral mix contained (DM basis) 23.9% CP, 1.12% Fat, 1.16% ADF, 9.51% Ca, 0.89% P, 1.51% S, 21.7% NPN, 1.99% Cl, 1.99% Salt, 3.0% Mg, 3.19% K, 8.07% Na, 680 PPM Fe, 1644 ppm Zn, 1195 ppm Mn, 498 ppm Cu, 25.1 ppm Co, 25.5 ppm I, 7.67 ppm Se, 147 KIU/kg vitamin A, 42.8 KIU/kg vitamin D3, 768 KIU/kg vitamin E. 4 Neutral detergent-soluble fiber. 5 starch + sugar + NDSF.

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60 5.65.75.85.966.16.26.36.402468101214Sampling HourRuminal pH ST-RUP ST+RUP SF-RUP SF+RUP SU-RUP SU+RUP Figure 3-1. Temporal patterns of ruminal pH by dietary treatment. Cows were fed following the 0 sampling hour. Acetate0102030405060708012345678910111213molar percentage Propionate051015202512345678910111213molar percentage Butyrate0246810121412345678910111213molar percentage BCVFA00.511.522.533.512345678910111213molar percentage Figure 3-2. Acetate, propionate, butyrate and BCVFA by sampling hour for ST-RUP ST+RUP SF-RUP SF+RUP and SU-RUP and SU+RUP Cows were fed following the hour 1 sampling.

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Table 3-2. Nutrient intake by dietary treatment. Diets 1 P values Contrasts 5 Item ST-RUP ST+ RUP SF-RUP SF+ RUP SU-RUP SU+ RUP SED 1234 NFC RUP NFC x RUP DMI 2 kg/d 25.0 25.2 23.9 23.5 25.2 24.6 0.79 0.02 0.56 0.65 0.09 0.03 0.36 0.84 CP intake, kg/d 4.15 ab 3.97 ab 3.98 ab 3.84 a 4.38 b 4.11 ab 0.15 0.01 0.04 0.82 0.84 0.01 0.88 0.54 NDF intake, kg/d 9.62 10.0 9.70 9.48 9.69 9.57 0.35 0.62 0.94 0.41 0.34 0.89 0.19 0.84 Starch intake, kg/d 5.83 a 6.03 a 3.52 b 3.41 b 3.33 b 3.14 b 0.19 <0.01 0.78 0.31 <0.01 0.09 0.13 0.76 NDSF intake, kg/d 0.54 a 0.52 a 1.31 bc 1.25 bc 1.02 ac 0.91 ac 0.20 <0.01 0.61 0.95 <0.01 0.03 0.80 0.85 Sugar intake, kg/d 1.05 a 1.05 a 1.79 b 1.72 b 3.31 c 3.44 c 0.10 <0.01 0.80 0.36 <0.01 <0.01 0.77 0.15 NFC 3 intake, kg/d 7.47 a 7.53 a 6.65 b 6.40 b 7.64 a 7.47 a 0.32 <0.01 0.55 0.76 0.02 <0.01 0.48 0.86 Ash intake, kg/d 1.63 abc 1.60 ac 1.58 ac 1.54 a 1.79 b 1.72 bc 0.06 0.01 0.25 0.92 0.24 <0.01 0.73 0.86 NE L 4 Mcal/kg of DMI 1.48 ab 1.42 a 1.48 ab 1.55 b 1.46 ab 1.51 ab 0.04 0.10 0.49 0.05 0.07 0.28 0.02 0.74 61 a,b,c Means in the same row with different superscripts differ, P < 0.05. 1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses + sucrose, -RUP = soybean meal, and +RUP = expeller soybean meal. 2 Dry matter intake. 3 Nonfiber carbohydrate intake =starch + sugar + NDSF 4 Estimated net energy of lactation per kg of DMI. 5 1 = ST vs. SU+SF for NFC, 2 = SU vs. SF for NFC, 3 = ST vs. SU+SF for NFC x RUP, and 4 = SU vs. SF for NFC x RUP

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Table 3-3. Milk production, milk composition, blood measures, and efficiency measures by dietary treatment. Diets 1 P values Contrasts 7 Item ST-RUP ST+ RUP SF-RUP SF+ RUP SU-RUP SU+ RUP 1234 SED NFC RUP NFC x RUP Milk, kg/d 41.0 a 39.1 ab 38.0 b 38.6 ab 40.1 ab 40.9 ab 1.10 0.01 0.82 0.15 0.33 0.01 0.05 0.94 3.5% FPCM 2 kg/d 38.9 a 36.8 ab 35.7 b 37.0 ab 38.2 ab 38.5 ab 1.26 0.06 0.84 0.13 0.53 0.03 0.05 0.58 Feed efficiency 3 1.58 1.47 1.51 1.59 1.52 1.56 0.06 0.72 0.90 0.03 0.46 0.78 0.01 0.54 Milk fat, kg/d 1.37 1.30 1.27 1.37 1.38 1.39 0.06 0.26 0.69 0.13 0.51 0.13 0.07 0.36 Milk fat, % 3.35 3.36 3.40 3.67 3.45 3.47 0.11 0.06 0.15 0.16 0.03 0.32 0.33 0.10 Milk protein, kg/d 1.13 a 1.06 ab 1.01 b 0.98 b 1.05 ab 1.05 ab 0.04 <0.01 0.18 0.49 0.01 0.06 0.28 0.60 Milk protein, % 2.80 2.76 2.67 2.64 2.70 2.62 0.03 <0.01 0.02 0.54 <0.01 0.97 0.66 0.30 SCC 2.51 2.78 2.23 2.66 2.75 3.25 0.40 0.15 0.14 0.91 0.75 0.14 0.69 0.91 N efficiency 4 0.27 0.26 0.25 0.26 0.24 0.25 0.01 0.06 0.76 0.40 0.03 0.29 0.18 0.83 Hematocrit 28.4 27.6 28.6 28.1 28.1 27.9 0.65 0.54 0.17 0.72 0.55 0.37 0.50 0.64 Plasma protein 7.52 7.68 7.69 7.82 7.77 7.66 0.16 0.36 0.55 0.43 0.17 0.75 0.42 0.29 MUN 5 mg/dl 13.6 13.2 13.1 12.1 12.8 12.2 0.58 0.05 0.07 0.66 0.02 0.88 0.48 0.58 Glucose, mg/dl 66.0 66.5 65.0 65.3 67.4 66.9 1.02 0.02 0.87 0.77 0.88 0.01 0.64 0.57 PUN 6 mg/dl 15.4 a 14.6 ab 14.3 ab 12.8 b 14.0 ab 13.4 ab 0.80 0.02 0.05 0.70 0.01 0.75 0.80 0.43 Insulin, ng/ml 0.52 0.49 0.46 0.47 0.53 0.54 0.04 0.09 0.73 0.79 0.84 0.03 0.50 1.00 62 a,b,c Means in the same row with different superscripts differ, P < 0.05. 1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses + sucrose, -RUP = soybean meal, and +RUP = expeller soybean meal. 2 3.5% fat and protein corrected milk yield. 3 Feed efficiency calculated as 3.5%FPCM divided by DMI. 4 N efficiency calculated as Milk N divided by N intake. 5 Milk urea N. 6 Plasma urea N. 7 1 = ST vs. SU+SF for NFC, 2 = SU vs. SF for NFC, 3 = ST vs. SU+SF for NFC x RUP, and 4 = SU vs. SF for NFC x RUP

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Table 3-4. Ruminal fluid measures by dietary treatment. Diets 1 P values Contrasts 4 Measure ST-RUP ST+ RUP SF-RUP SF+ RUP SU-RUP SU+ RUP SED 1234 NFC RUP NFC xRUP Total VFA, mM 127 123 129 125 134 124 6.24 0.74 0.13 0.72 0.52 0.66 0.62 0.52 VFA in molar % Acetate 63.2 66.5 65.0 65.0 62.5 63.3 1.43 0.14 0.12 0.24 0.30 0.08 0.11 0.75 Propionate 21.7 19.8 19.6 19.5 20.9 20.4 1.18 0.32 0.26 0.55 0.38 0.25 0.30 0.84 Butyrate 9.70 a 9.07 a 10.1 ab 10.6 ab 12.0 b 11.7 b 0.55 <0.01 0.59 0.36 0.01 0.01 0.33 0.33 BCVFA 2 2.98 2.82 2.58 2.31 1.81 1.83 0.37 0.01 0.53 0.86 0.01 0.05 0.93 0.59 A:P ratio 3 2.96 3.30 3.25 3.38 3.09 3.17 0.26 <0.01 <0.01 0.04 0.01 0.07 0.25 0.77 Ruminal fluid pH 5.99 5.98 6.11 6.03 5.83 6.07 0.39 0.26 0.22 0.53 0.53 0.12 0.39 0.43 63 a,b Means in the same row with different superscripts differ, P < 0.05. 1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses + sucrose, -RUP = soybean meal, and +RUP = expeller soybean meal. 2 Branch chain volatile fatty acids include isobutyrate, methylbutyrate, and isovalerate 3 Acetate to propionate ratio 4 1 = ST vs. SU+SF for NFC, 2 = SU vs. SF for NFC, 3 = ST vs. SU+SF for NFC x RUP, and 4 = SU vs. SF for NFC x RUP

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Table 3-5. Residual NDF by hour of in situ incubation and dietary treatment. Diets 1 P values Contrasts 3 ST-RUP ST+ RUP SF-RUP SF+ RUP SU-RUP SU+ RUP UP1234 SED NFC RUP NFC x R Remaining NDF %, as a % of intial NDF 0 2 0.662 0.665 0.663 0.667 0.665 0.664 0.003 1.00 0.96 1.00 0.99 0.99 0.94 1.00 6 0.627 ac 0.628 ac 0.623 bc 0.637 a 0.631 abc 0.615 b 0.004 0.04 0.95 <0.01 0.38 0.01 0.90 0.01 12 0.597 b 0.565 a 0.586 ab 0.591 b 0.597 b 0.579 ab 0.008 0.47 <0.01 0.01 0.24 0.89 0.01 0.12 18 0.558 ac 0.529 b 0.530 b 0.558 c 0.582 c 0.566 c 0.008 <0.01 0.20 <0.01 0.01 <0.01 0.01 0.01 24 0.533 a 0.489 b 0.519 ab 0.527 a 0.551 a 0.518 ab 0.012 0.05 <0.01 0.01 0.02 0.19 0.04 0.02 30 0.486 ac 0.446 b 0.446 b 0.487 c 0.514 c 0.478 c 0.011 <0.01 0.07 <0.01 0.04 0.01 0.01 0.01 48 0.402 0.383 0.378 0.396 0.403 0.402 0.010 0.12 0.90 0.05 0.84 0.04 0.05 0.21 Remaining DM %, as a % of initial DM 0 0.762 0.762 0.762 0.762 0.762 0.762 0.001 1.00 0.99 1.00 1.00 1.00 0.99 1.00 6 0.707 0.707 0.702 0.713 0.709 0.695 0.006 0.46 0.73 0.04 0.57 0.24 0.74 0.16 12 0.668 0.630 0.657 0.658 0.664 0.647 0.009 0.36 0.01 0.02 0.19 0.74 0.01 0.17 18 0.621 0.589 0.595 0.619 0.645 0.631 0.008 <0.01 0.09 0.01 0.01 <0.01 0.01 0.01 24 0.593 0.548 0.585 0.588 0.614 0.579 0.013 0.05 0.01 0.03 0.02 0.30 0.09 0.06 30 0.540 0.500 0.507 0.546 0.574 0.534 0.012 0.01 0.03 <0.01 0.01 0.01 0.01 0.01 48 0.456 0.434 0.432 0.452 0.460 0.454 0.012 0.23 0.69 0.07 0.63 0.09 0.08 0.17 64 a,b,c Means in the same row with different superscripts differ, P < 0.05. 1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses + sucrose, -RUP = soybean meal, and +RUP = expeller soybean meal. 2 Hour of fermentation 3 1 = ST vs. SU+SF for NFC, 2 = SU vs. SF for NFC, 3 = ST vs. SU+SF for NFC x RUP, and 4 = SU vs. SF for NFC x RUP

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APPENDIX A MILK PRODUCTION, COMPOSITION, AND PLASMA MEASURES Table A-1. Averages for milk production, fat percent, protein percent, milk urea N (MUN), and somatic cell count (SCC) by cow period, and diet. Diets 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP. Cow Period Diet Milk, kg/d Fat % Protein % MUN, mg/dl SCC 2680 1 3 36.7 3.5 2.9 10.5 6.0 2682 1 2 37.6 2.9 2.5 13.7 5.8 2760 1 6 44.7 3.8 2.6 13.2 0.4 2824 1 5 46.7 3.3 2.4 13.0 5.1 2931 1 6 46.7 3.5 2.6 10.7 3.9 2986 1 2 44.4 2.9 2.8 13.2 0.2 3136 1 3 40.6 3.5 2.6 10.7 0.0 3165 1 2 42.8 3.4 2.9 11.9 0.0 3319 1 1 43.1 3.7 2.9 13.1 0.0 3338 1 6 50.3 3.3 2.3 13.4 6.3 3340 1 5 39.7 3.7 2.5 13.7 4.4 3344 1 5 46.8 2.9 2.5 11.0 5.8 3444 1 2 42.3 2.7 2.7 11.1 4.7 3445 1 6 46.1 3.3 2.6 13.9 6.5 3448 1 4 46.2 3.2 2.4 14.6 0.0 3532 1 3 44.8 3.2 2.6 12.4 0.1 3560 1 4 40.6 3.4 2.7 12.1 1.7 3588 1 5 41.6 3.3 2.9 10.6 4.6 3621 1 1 43.9 3.0 2.7 11.3 0.0 3622 1 4 38.4 3.6 2.6 9.3 1.6 3633 1 3 45.0 3.2 2.4 10.0 0.0 3661 1 2 31.1 3.4 2.8 12.2 1.2 3668 1 1 48.6 3.1 2.3 12.5 1.7 3703 1 2 38.3 4.3 2.9 13.1 3.9 3708 1 4 43.4 4.1 2.4 11.4 2.1 3738 1 4 42.3 3.7 2.4 12.7 1.4 3755 1 3 37.9 3.0 2.4 11.2 2.1 3801 1 1 35.5 3.2 2.7 12.7 5.8 5882 1 5 35.5 3.8 2.6 10.6 0.0 5896 1 4 34.1 3.6 2.4 12.3 0.2 6000 1 1 42.9 3.2 2.6 13.2 1.0 6029 1 4 39.9 4.1 2.7 11.7 0.4 6072 1 3 43.2 3.2 2.7 10.8 1.2 6078 1 1 40.2 3.1 2.3 14.7 0.2 6079 1 2 42.9 2.9 2.8 13.4 0.6 6095 1 6 47.3 3.4 2.7 14.6 0.5 65

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66 Table A-1. Continued Cow Period Diet Milk, kg/d Fat % Protein % MUN, mg/dl SCC 6138 1 3 41.9 3.3 2.5 17.2 0.0 6162 1 6 45.4 3.6 2.5 16.0 3.4 2680 2 2 36.3 3.6 3.1 14.0 6.3 2682 2 3 33.0 2.9 2.7 14.9 7.3 2760 2 3 42.3 3.7 2.8 14.3 0.1 2824 2 6 47.3 3.2 2.4 13.3 6.8 2931 2 5 42.7 3.5 2.8 13.5 5.6 2986 2 5 42.7 3.8 3.1 14.7 0.6 3136 2 5 43.7 3.5 2.8 11.1 0.2 3165 2 4 41.0 4.4 3.3 12.6 0.0 3319 2 3 39.6 4.0 3.1 14.7 0.0 3338 2 4 50.7 3.6 2.5 15.3 5.3 3340 2 3 40.4 3.2 2.7 18.1 5.0 3344 2 1 41.1 2.9 2.9 12.8 6.0 3444 2 1 41.2 3.3 3.0 13.2 4.8 3445 2 6 41.0 3.0 2.9 13.5 7.7 3448 2 1 49.5 3.4 2.8 16.0 0.2 3532 2 1 39.9 3.3 2.7 15.5 1.3 3560 2 2 36.4 3.1 3.1 14.3 2.4 3588 2 5 37.7 3.9 3.0 12.9 2.8 3621 2 5 46.9 3.4 2.8 12.6 1.5 3622 2 6 40.5 3.7 2.6 15.1 1.6 3633 2 6 45.6 3.6 2.6 13.0 0.1 3661 2 6 41.2 3.8 2.9 13.1 1.1 3668 2 1 42.2 3.5 2.5 14.4 0.5 3703 2 2 34.1 4.2 3.3 13.0 4.8 3708 2 4 37.7 3.3 2.6 12.8 5.0 3738 2 5 42.3 3.7 2.7 16.4 0.8 3755 2 4 39.4 3.0 2.5 14.5 4.1 3801 2 6 36.3 3.4 2.7 12.3 5.9 5882 2 2 30.8 4.1 3.0 10.5 0.0 5896 2 5 29.7 3.8 2.7 15.5 1.3 6000 2 4 42.1 3.7 2.7 12.9 1.0 6029 2 3 40.7 4.2 2.9 16.6 0.8 6072 2 4 37.7 4.3 3.0 13.1 0.8 6078 2 2 35.2 3.8 2.4 24.7 2.3 6079 2 3 41.8 3.8 2.9 16.6 0.7 6095 2 2 49.9 3.4 2.9 13.5 0.1 6138 2 3 41.1 3.6 2.7 19.2 0.5 6162 2 1 45.0 3.8 2.9 16.0 2.5 2680 3 3 30.6 3.6 2.9 11.0 4.9 2682 3 6 32.0 3.2 2.4 7.6 7.7 2760 3 2 39.6 4.1 2.8 8.7 7.0 2824 3 3 34.4 2.8 2.3 12.9 6.5 2931 3 6 42.2 3.1 2.6 8.7 5.8 2986 3 4 32.2 4.7 2.7 9.6 2.6 3136 3 3 36.2 3.3 2.7 10.3 0.7

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67 Table A-1. Continued Cow Period Diet Milk, kg/d Fat % Protein % MUN, mg/dl SCC 3165 3 2 39.1 3.6 3.2 12.8 0.8 3319 3 1 38.1 3.4 3.2 12.3 0.0 3338 3 4 37.4 2.9 2.4 11.6 6.2 3340 3 3 33.5 3.4 2.5 13.5 4.5 3344 3 5 34.7 2.7 2.7 10.7 4.7 3444 3 2 39.4 2.9 3.0 11.9 4.8 3445 3 2 41.9 3.2 2.9 11.3 5.8 3448 3 6 42.4 3.2 2.5 9.7 0.1 3532 3 1 38.5 2.8 2.7 16.0 0.9 3560 3 2 33.4 2.9 3.0 10.9 3.1 3588 3 1 37.6 3.3 3.0 10.6 4.5 3621 3 5 39.0 3.1 2.7 10.3 2.9 3622 3 4 29.0 3.4 2.5 10.6 2.5 3633 3 5 43.0 3.2 2.4 11.6 0.6 3661 3 6 36.8 4.1 2.7 10.0 3.7 3668 3 3 35.3 3.2 2.3 11.0 0.3 3703 3 4 25.0 3.7 2.9 10.1 5.4 3708 3 6 26.4 2.8 2.4 9.1 6.5 3738 3 2 39.7 3.2 2.7 14.1 1.9 3755 3 1 37.4 3.2 2.6 14.7 4.0 3801 3 1 34.8 3.4 2.9 10.7 5.9 5882 3 1 33.7 3.7 3.0 12.8 0.0 5896 3 2 23.8 3.8 2.6 12.9 0.4 6000 3 3 30.5 3.6 2.4 11.4 3.0 6029 3 4 36.3 3.7 2.7 13.2 2.6 6072 3 1 38.4 3.6 2.9 12.2 2.4 6079 3 6 38.7 3.4 2.8 10.3 4.1 6095 3 6 47.2 3.7 2.6 11.5 2.4 6138 3 5 37.6 3.3 2.6 16.3 1.8 6162 3 4 38.3 3.7 2.5 12.4 3.3 Table A-2. Averages for plasma urea nitrogen (PUN), glucose, and insulin by cow, period, and diet. Diets 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP. PUN, Glucose, Insulin, Cow Period Diet mg/dl mg/dl ng/ml 2680 1 3 13.1 63.9 0.43 2682 1 2 15.1 67.5 0.50 2760 1 6 14.7 71.6 0.32 2824 1 5 12.5 63.8 0.56 2931 1 6 12.1 70.9 0.59 2986 1 2 14.2 60.8 0.32 3136 1 3 13.1 65.8 0.31 3165 1 2 18.9 66.6 0.41 3319 1 1 16.0 61.8 0.67 3338 1 6 19.5 67.7 0.61

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68 Table A-2. Continued PUN, Glucose, Insulin, Cow Period Diet mg/dl mg/dl ng/ml 3340 1 5 16.2 64.8 0.54 3560 2 2 15.2 70.0 0.68 3588 2 5 16.3 71.0 0.61 3344 1 5 11.5 64.9 0.48 3444 1 2 10.9 71.3 0.49 3445 1 6 14.1 69.9 0.56 3448 1 4 13.4 65.0 0.40 3532 1 3 13.7 60.7 0.46 3560 1 4 10.6 70.2 0.58 3588 1 5 14.9 68.0 0.59 3621 1 1 14.8 66.1 0.49 3622 1 4 9.6 67.6 0.33 3633 1 3 10.3 60.8 0.43 3661 1 2 15.1 75.1 0.52 3668 1 1 15.2 65.6 0.61 3703 1 2 18.2 64.4 0.76 3708 1 4 16.5 65.0 0.47 3738 1 4 15.0 63.0 0.37 3755 1 3 15.2 61.6 0.51 3801 1 1 14.4 65.1 0.67 5882 1 5 10.3 61.5 0.50 5896 1 4 12.0 65.0 0.52 6000 1 1 13.5 66.4 0.54 6029 1 4 11.2 63.9 0.48 6072 1 3 11.1 68.6 0.55 6078 1 1 14.3 67.6 0.43 6079 1 2 13.4 63.5 0.44 6095 1 6 14.9 61.1 0.49 6138 1 3 17.0 61.5 0.72 6162 1 6 15.5 62.4 0.48 2680 2 2 19.4 72.1 -2682 2 3 14.6 71.6 0.44 2760 2 3 18.1 74.3 0.48 2824 2 6 15.5 63.8 0.58 2931 2 5 13.9 68.7 0.53 2986 2 5 16.4 65.2 0.43 3136 2 5 13.8 68.1 0.65 3165 2 4 14.8 67.2 0.56 3319 2 3 16.7 66.2 0.54 3338 2 4 18.3 66.2 0.57 3340 2 3 19.3 65.9 0.68 3344 2 1 14.0 67.2 0.63 3444 2 1 11.3 71.5 -3445 2 6 14.0 72.5 0.83 3448 2 1 18.4 65.9 0.38 3532 2 1 20.8 60.4 0.44

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69 Table A-2. Continued PUN, Glucose, Insulin, Cow Period Diet mg/dl mg/dl ng/ml 3621 2 5 13.6 66.7 0.61 3708 3 6 8.9 61.7 -3738 3 2 15.7 60.3 0.69 3622 2 6 19.2 65.0 0.52 3633 2 6 15.3 67.7 0.56 3661 2 6 15.8 75.4 0.59 3668 2 1 16.8 71.1 0.41 3703 2 2 15.7 71.0 0.37 3708 2 4 14.7 62.7 0.41 3738 2 5 18.7 68.3 0.43 3755 2 4 14.2 64.8 0.40 3801 2 6 13.7 70.8 0.43 5882 2 2 10.6 63.5 0.51 5896 2 5 12.8 66.6 0.40 6000 2 4 13.5 68.1 0.47 6029 2 3 15.4 66.9 0.40 6072 2 4 14.2 66.0 0.57 6078 2 2 19.9 62.7 0.34 6079 2 3 15.1 65.4 0.36 6095 2 2 14.0 65.2 0.30 6138 2 3 16.6 65.9 0.44 6162 2 1 15.4 62.6 0.26 2680 3 3 13.1 63.0 0.42 2682 3 6 7.9 75.8 0.40 2760 3 2 9.4 73.1 0.34 2824 3 3 10.9 58.1 0.28 2931 3 6 7.8 61.7 0.47 2986 3 4 11.0 59.2 0.29 3136 3 3 12.4 61.6 0.28 3165 3 2 12.0 64.3 0.24 3319 3 1 16.9 61.6 0.26 3338 3 4 13.7 59.3 0.42 3340 3 3 17.1 63.6 0.37 3344 3 5 12.9 69.3 0.33 3444 3 2 ---3445 3 2 ---3448 3 6 11.4 59.3 -3532 3 1 18.9 60.6 0.37 3560 3 2 10.0 73.0 0.75 3588 3 1 15.3 67.8 0.65 3621 3 5 12.2 68.5 0.70 3622 3 4 19.1 56.7 0.38 3633 3 5 15.3 69.4 -3661 3 6 10.4 72.3 0.57 3668 3 3 15.6 65.1 0.66 3703 3 4 12.1 61.8 0.47

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70 Table A-2. Continued PUN, Glucose, Insulin, Cow Period Diet mg/dl mg/dl ng/ml 3755 3 1 17.6 62.0 0.49 3801 3 1 13.3 66.4 0.76 5882 3 1 12.1 61.8 0.66 5896 3 2 15.0 64.9 0.63 6000 3 3 12.0 67.1 0.53 6029 3 4 12.5 61.5 0.69 6072 3 1 12.5 70.5 0.72 6079 3 6 10.4 63.9 0.64 6095 3 6 11.7 64.4 0.42 6138 3 5 14.6 63.0 0.63 6162 3 4 12.3 59.3 0.50

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APPENDIX B RUMINAL PH AND VOLATILE FATTY ACIDS

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72 Table B-1. Volatile fatty acids (VFA) and rumen pH by cow, period, hour of sampling, and diet. Diet 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------2682 1 0 2 98.50 27.90 0.68 12.90 1.95 0.42 0.67 143.02 5.96 2682 1 1 2 99.82 28.73 0.66 12.28 1.97 0.44 0.64 144.55 5.92 2682 1 2 2 84.60 25.22 0.59 10.47 1.88 0.37 0.67 123.79 5.81 2682 1 3 2 85.76 24.97 0.40 9.07 1.76 0.31 0.59 122.86 6.12 2682 1 4 2 82.11 24.02 0.40 9.19 1.65 0.33 0.62 118.32 5.98 2682 1 5 2 82.99 25.98 0.49 9.47 1.79 0.34 0.64 121.70 5.86 2682 1 6 2 80.19 23.55 0.61 10.74 2.05 0.42 0.92 118.47 6.07 2682 1 7 2 78.17 24.83 0.58 10.93 2.02 0.39 0.83 117.75 5.98 2682 1 8 2 73.23 22.25 0.54 9.76 1.77 0.34 1.01 108.90 6.04 2682 1 9 2 77.88 23.27 0.55 10.60 1.91 0.37 1.42 116.01 5.92 2682 1 10 2 77.12 23.91 0.54 10.54 1.88 0.35 1.46 115.81 6.11 2682 1 11 2 78.17 24.54 0.53 10.90 1.86 0.37 2.38 118.74 5.99 2682 1 12 2 80.72 24.60 0.52 10.92 1.87 0.38 2.44 121.44 5.90 2682 2 0 5 76.02 16.90 0.76 9.97 2.05 0.57 2.27 108.56 5.79 2682 2 1 5 81.59 20.48 0.88 10.41 2.22 0.57 1.51 117.67 5.53 2682 2 2 5 103.01 29.04 1.14 14.53 2.90 0.73 3.05 154.40 5.54 2682 2 3 5 97.91 26.51 0.99 12.88 2.92 0.69 2.85 144.74 5.63 2682 2 4 5 89.36 23.46 0.88 12.12 2.63 0.59 2.55 131.57 5.65 2682 2 5 5 75.20 19.78 0.53 10.31 2.22 0.43 3.04 111.50 5.61

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2824 1 6 4 87.14 29.12 0.40 17.53 1.86 0.30 3.65 140.00 6.04 73Table B-1. Continued IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------2682 2 6 5 76.35 21.86 0.58 11.26 2.32 0.42 3.24 116.02 5.74 2682 2 7 5 78.99 22.35 0.70 11.08 2.43 0.42 2.52 118.49 5.73 2682 2 8 5 68.39 18.89 0.40 10.16 2.00 0.33 3.10 103.26 5.61 2682 2 9 5 73.27 19.53 0.48 10.42 2.02 0.36 3.24 109.32 5.70 2682 2 10 5 88.10 24.92 0.65 13.20 2.44 0.42 4.01 133.75 5.63 2682 2 11 5 90.69 25.65 0.61 13.64 2.58 0.46 4.08 137.70 5.85 2682 2 12 5 78.58 21.12 0.61 12.14 2.39 0.50 3.23 118.57 6.26 2682 3 0 3 77.48 16.99 0.51 10.98 1.52 0.45 2.42 110.36 6.49 2682 3 1 3 85.00 22.67 0.72 13.86 1.88 0.55 3.09 127.77 6.23 2682 3 2 3 76.01 27.54 1.20 16.97 2.36 0.64 4.33 129.04 6.35 2682 3 3 3 87.24 31.26 0.79 16.21 1.94 0.46 3.54 141.44 6.03 2682 3 4 3 87.79 27.52 0.68 16.30 2.08 0.46 4.25 139.08 6.15 2682 3 5 3 81.74 26.30 0.62 16.29 1.98 0.39 4.22 131.55 6.28 2682 3 6 3 78.75 24.42 0.51 14.72 1.77 0.29 3.55 124.01 6.29 2682 3 7 3 72.74 22.81 0.28 13.45 1.52 0.28 3.41 114.48 6.40 2682 3 8 3 68.57 21.43 0.24 13.32 1.32 0.25 3.20 108.33 6.40 2682 3 9 3 67.12 19.30 0.38 12.45 1.33 0.25 2.89 103.72 6.37 2682 3 10 3 77.86 20.79 0.35 13.81 1.50 0.28 3.17 117.75 6.32 2682 3 11 3 74.90 19.02 0.38 13.03 1.54 0.30 2.89 112.06 6.41 2682 3 12 3 70.45 17.18 0.38 11.91 1.50 0.29 2.64 104.35 6.38 2824 1 0 4 69.99 20.58 0.20 11.63 1.39 0.09 2.51 106.40 6.84 2824 1 1 4 77.62 22.51 0.26 12.08 1.30 0.13 2.27 116.17 6.40 2824 1 2 4 78.44 25.05 0.32 14.03 1.48 0.26 2.69 122.27 6.22 2824 1 3 4 78.45 25.13 0.38 14.66 1.54 0.30 2.86 123.33 6.29 2824 1 4 4 75.57 24.70 0.31 14.60 1.58 0.32 2.89 119.97 6.31 2824 1 5 4 94.21 30.57 0.39 18.75 1.97 0.35 3.36 149.60 6.19

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2824 3 7 6 80.30 26.49 0.63 13.24 1.67 0.41 3.81 126.54 6.15 74Table B-1. Continued IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------2824 1 7 4 84.27 27.23 0.30 16.20 1.88 0.30 3.49 133.67 6.32 2824 1 8 4 92.51 30.28 0.36 18.00 2.18 0.35 4.11 147.79 6.37 2824 1 9 4 78.94 25.81 0.37 14.95 1.86 0.29 3.64 125.86 6.37 2824 1 10 4 75.42 24.28 0.32 13.71 1.64 0.31 3.23 118.91 6.18 2824 1 11 4 77.02 24.69 0.28 14.15 1.81 0.30 3.57 121.82 6.25 2824 1 12 4 70.99 23.32 0.29 12.67 1.64 0.27 2.90 112.07 6.30 2824 2 0 1 81.04 24.45 0.28 12.81 1.37 0.22 3.57 123.74 6.10 2824 2 1 1 98.22 30.14 0.38 15.82 1.44 0.23 3.87 150.11 6.06 2824 2 2 1 97.17 33.23 0.39 17.45 1.75 0.25 4.18 154.42 6.03 2824 2 3 1 86.66 28.04 0.39 14.94 1.66 0.21 3.87 135.77 6.02 2824 2 4 1 85.80 29.16 0.29 15.58 1.58 0.20 4.18 136.80 5.95 2824 2 5 1 79.88 26.21 0.31 13.77 1.34 0.16 3.55 125.22 5.78 2824 2 6 1 77.03 27.52 0.31 14.63 1.48 0.16 4.01 125.13 5.89 2824 2 7 1 79.80 26.70 0.33 13.36 1.28 0.16 3.38 125.03 5.83 2824 2 8 1 80.55 29.09 0.38 15.89 1.67 0.19 4.34 132.11 5.76 2824 2 9 1 79.49 29.68 0.30 15.86 1.54 0.19 4.34 131.40 5.79 2824 2 10 1 79.68 29.97 0.32 15.93 1.55 0.18 4.36 132.00 5.81 2824 2 11 1 78.04 27.38 0.25 13.76 1.40 0.17 3.70 124.70 5.78 2824 2 12 1 75.01 25.26 0.20 12.85 1.32 0.14 3.57 118.35 5.80 2824 3 0 6 82.35 25.36 0.54 12.22 1.50 0.38 3.31 125.66 6.09 2824 3 1 6 84.17 27.66 0.68 13.92 1.73 0.44 3.88 132.48 6.01 2824 3 2 6 78.20 29.21 0.78 14.80 1.96 0.49 4.35 129.80 6.00 2824 3 3 6 93.30 32.40 0.80 15.46 2.05 0.53 4.41 148.95 6.04 2824 3 4 6 89.34 30.59 0.74 14.45 1.99 0.51 4.25 141.87 6.22 2824 3 5 6 88.67 30.24 0.80 15.44 2.12 0.59 4.48 142.33 6.28 2824 3 6 6 80.07 27.88 0.83 14.37 1.89 0.45 4.09 129.57 6.52

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3755 2 7 6 79.19 21.70 0.64 13.75 2.41 0.27 3.38 121.34 5.72 3755 2 8 6 69.55 19.09 0.55 11.87 1.97 0.26 3.34 106.63 5.62 75 Table B-1. Continued IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------2824 3 8 6 86.44 27.66 0.59 13.52 1.70 0.42 3.85 134.18 6.05 2824 3 9 6 93.88 29.77 0.68 15.13 1.73 0.42 4.01 145.63 6.08 2824 3 10 6 87.18 30.28 0.70 13.21 1.62 0.43 3.87 137.28 6.19 2824 3 11 6 86.75 29.87 0.66 14.25 1.64 0.41 3.97 137.56 6.03 2824 3 12 6 96.10 32.76 0.68 16.65 1.86 0.50 4.62 153.16 6.10 3755 1 0 3 76.65 20.46 0.68 11.37 1.63 0.30 2.39 113.48 6.26 3755 1 1 3 86.10 26.73 0.69 13.81 1.70 0.30 2.85 132.17 6.30 3755 1 2 3 82.73 26.96 0.74 13.98 2.25 0.43 4.14 131.22 6.00 3755 1 3 3 88.83 29.53 0.76 16.89 2.45 0.46 4.32 143.24 6.09 3755 1 4 3 89.76 28.79 0.78 15.62 2.57 0.44 4.46 142.42 6.13 3755 1 5 3 85.60 26.85 0.73 13.65 2.30 0.45 3.93 133.51 6.27 3755 1 6 3 81.14 26.12 0.75 14.32 2.42 0.46 3.58 128.78 6.15 3755 1 7 3 79.27 23.87 0.77 12.79 2.39 0.50 3.36 122.97 6.18 3755 1 8 3 78.49 23.20 0.85 12.35 2.28 0.43 3.04 120.64 5.97 3755 1 9 3 81.06 24.17 0.85 13.47 2.40 0.47 3.08 125.49 6.23 3755 1 10 3 75.03 20.22 0.66 10.87 2.09 0.42 2.80 112.09 5.89 3755 1 11 3 74.72 19.62 0.67 10.67 2.29 0.35 2.52 110.85 6.09 3755 1 12 3 72.11 23.36 0.70 12.16 1.95 0.36 2.82 113.45 6.29 3755 2 0 6 71.19 17.27 0.69 11.12 1.85 0.32 2.59 105.03 5.92 3755 2 1 6 86.56 23.04 0.72 14.21 2.18 0.37 2.93 130.01 5.73 3755 2 2 6 77.69 20.21 0.68 12.28 2.32 0.30 2.91 116.39 5.73 3755 2 3 6 85.24 23.62 0.70 14.08 2.37 0.36 3.34 129.71 5.74 3755 2 4 6 94.70 25.90 0.81 16.07 2.93 0.36 4.05 144.82 5.76 3755 2 5 6 76.90 20.97 0.65 13.00 2.25 0.29 3.31 117.38 5.98 3755 2 6 6 73.55 19.47 0.54 12.15 2.44 0.28 3.33 111.75 5.75

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5896 1 8 5 79.40 22.27 0.68 12.96 1.25 0.30 3.15 120.02 5.79 5896 1 9 5 78.97 22.39 0.73 12.43 1.40 0.33 3.00 119.25 6.14 76 Table B-1. Continued IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------3755 2 9 6 66.81 17.11 0.50 10.31 1.60 0.26 3.14 99.73 6.04 3755 2 10 6 69.61 19.91 0.51 12.40 1.61 0.25 3.10 107.38 5.86 3755 2 11 6 78.92 24.33 0.53 14.66 2.09 0.23 3.13 123.88 5.81 3755 2 12 6 72.25 21.79 0.49 12.82 2.08 0.27 3.36 113.05 6.01 3755 3 0 4 85.40 22.44 0.78 10.37 1.76 0.39 2.32 123.46 6.29 3755 3 1 4 83.73 25.21 0.73 11.43 2.07 0.44 2.80 126.40 6.16 3755 3 2 4 91.51 31.22 0.87 14.97 2.15 0.53 4.27 145.51 6.19 3755 3 3 4 95.12 30.84 0.82 14.34 2.09 0.49 3.88 147.58 6.18 3755 3 4 4 99.97 31.32 0.96 14.87 2.55 0.67 4.01 154.34 6.05 3755 3 5 4 79.01 29.31 0.95 13.54 2.64 0.52 3.46 129.42 6.16 3755 3 6 4 81.27 27.42 0.95 13.54 3.17 0.59 3.35 130.28 6.07 3755 3 7 4 85.04 28.35 0.90 13.39 2.46 0.52 3.02 133.67 6.19 3755 3 8 4 85.71 29.32 1.00 13.81 2.83 0.65 3.58 136.90 6.17 3755 3 9 4 78.26 24.19 0.86 11.48 2.18 0.51 2.65 120.13 6.17 3755 3 10 4 83.81 27.82 0.97 13.33 2.53 0.56 3.13 132.14 5.98 3755 3 11 4 67.99 22.20 0.82 10.51 1.90 0.39 2.50 106.29 5.91 3755 3 12 4 82.49 26.96 0.89 12.85 2.19 0.45 3.21 129.03 5.91 5896 1 0 5 69.23 22.00 0.67 8.37 0.88 0.22 1.01 102.38 6.17 5896 1 1 5 78.42 25.01 0.94 11.01 1.30 0.35 2.27 119.30 6.04 5896 1 2 5 99.09 32.08 1.80 14.86 1.82 0.56 3.79 153.99 5.95 5896 1 3 5 87.32 25.81 0.87 13.01 1.42 0.36 2.43 131.22 5.99 5896 1 4 5 77.63 24.41 0.83 11.62 1.19 0.32 2.97 118.97 5.81 5896 1 5 5 78.41 24.37 0.76 12.34 1.10 0.29 3.12 120.37 5.94 5896 1 6 5 92.28 30.01 0.97 15.45 1.54 0.40 4.23 144.88 5.67 5896 1 7 5 85.07 29.41 0.82 14.59 1.25 0.33 4.32 135.80 6.04

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5896 3 9 1 77.53 21.83 0.63 9.39 1.61 0.33 2.22 113.53 6.30 5896 3 10 1 79.76 23.27 0.68 10.23 1.54 0.36 2.32 118.16 6.12 77 Table B-1. Continued IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------5896 1 10 5 88.29 26.87 0.85 14.38 1.64 0.58 3.91 136.51 5.79 5896 1 11 5 81.88 23.62 0.73 12.16 1.31 0.49 3.03 123.22 5.90 5896 1 12 5 81.58 23.32 0.76 11.98 1.37 0.37 2.66 122.04 5.94 5896 2 0 2 75.16 21.10 0.59 12.51 1.07 0.28 2.54 113.25 6.13 5896 2 1 2 87.28 28.26 0.68 15.76 1.44 0.32 3.52 137.26 6.06 5896 2 2 2 86.99 29.02 0.79 16.64 1.52 0.33 3.59 138.87 5.99 5896 2 3 2 92.98 31.50 0.84 17.55 1.80 0.36 4.16 149.21 6.04 5896 2 4 2 91.21 31.95 0.82 18.61 1.88 0.33 4.09 148.88 5.98 5896 2 5 2 96.81 32.20 0.87 18.74 1.90 0.35 4.45 155.31 6.23 5896 2 6 2 80.65 31.68 0.88 19.57 1.72 0.38 4.94 139.82 6.09 5896 2 7 2 74.84 25.65 0.64 14.53 1.28 0.28 3.26 120.49 6.14 5896 2 8 2 87.69 31.39 0.83 19.54 1.81 0.37 4.51 146.14 6.11 5896 2 9 2 78.38 26.96 0.69 13.81 1.53 0.34 3.76 125.47 5.99 5896 2 10 2 78.65 34.04 0.84 17.90 1.71 0.35 4.53 138.01 6.01 5896 2 11 2 93.43 35.17 0.79 19.78 1.71 0.33 4.69 155.91 5.95 5896 2 12 2 79.93 29.85 0.67 16.91 1.31 0.31 4.80 133.77 5.99 5896 3 0 1 83.42 20.94 0.72 10.26 1.26 0.40 2.79 119.80 6.27 5896 3 1 1 83.96 22.84 0.93 10.58 1.63 0.36 2.33 122.62 6.22 5896 3 2 1 90.75 23.56 0.84 10.93 1.52 0.38 2.28 130.26 6.22 5896 3 3 1 88.90 23.15 0.86 10.66 1.55 0.37 2.64 128.14 6.23 5896 3 4 1 91.89 23.78 0.82 11.45 1.63 0.49 2.58 132.64 6.08 5896 3 5 1 89.27 23.08 0.76 10.95 1.83 0.36 2.35 128.59 6.28 5896 3 6 1 85.83 25.11 0.89 12.16 2.87 0.56 2.91 130.32 5.94 5896 3 7 1 75.47 21.56 0.75 9.79 2.81 0.50 2.29 113.17 6.07 5896 3 8 1 69.67 19.57 0.64 8.77 1.91 0.36 2.02 102.94 6.11

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6078 2 10 3 72.38 22.93 0.90 11.35 2.96 0.37 2.80 113.68 5.77 6078 2 11 3 75.49 25.56 0.87 12.10 3.12 0.35 2.68 120.17 5.65 78 Table B-1. Continued IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------5896 3 11 1 85.21 27.37 0.79 12.22 1.55 0.34 2.64 130.12 5.98 5896 3 12 1 86.38 26.58 0.82 11.81 1.53 0.31 2.71 130.13 6.06 6078 1 0 6 72.24 22.29 0.68 10.05 1.91 0.41 2.15 109.74 6.26 6078 1 1 6 84.18 26.80 0.91 13.01 2.57 0.53 2.67 130.65 6.15 6078 1 2 6 83.15 25.92 0.92 15.12 3.09 0.59 3.11 131.88 6.04 6078 1 3 6 79.48 26.20 0.84 12.75 2.93 0.48 2.81 125.48 6.16 6078 1 4 6 78.21 24.66 0.81 11.93 2.58 0.43 2.70 121.32 5.90 6078 1 5 6 86.06 28.59 0.83 14.14 3.05 0.49 3.05 136.21 5.92 6078 1 6 6 84.08 28.27 0.83 13.50 2.62 0.45 2.84 132.59 6.03 6078 1 7 6 86.95 29.39 0.88 14.98 3.02 0.47 3.00 138.69 6.06 6078 1 8 6 94.81 32.23 1.04 16.03 3.23 1.27 3.26 151.87 5.73 6078 1 9 6 92.19 30.90 0.91 15.21 2.98 1.24 3.30 146.74 6.07 6078 1 10 6 75.38 27.41 0.83 12.16 2.44 1.02 2.61 121.85 6.04 6078 1 11 6 79.07 29.98 0.96 13.92 2.74 0.43 2.97 130.07 6.26 6078 1 12 6 85.88 32.49 0.98 15.55 3.04 0.47 3.11 141.52 6.28 6078 2 0 3 70.54 23.45 0.89 10.74 2.06 0.44 2.09 110.22 5.85 6078 2 1 3 89.09 27.22 1.10 13.62 2.93 0.54 3.04 137.54 5.93 6078 2 2 3 90.83 30.78 1.35 15.63 3.89 0.61 3.44 146.52 5.77 6078 2 3 3 88.61 26.99 1.06 12.82 3.63 0.53 3.11 136.75 5.69 6078 2 4 3 94.46 28.89 1.12 14.56 4.29 0.75 3.42 147.49 5.69 6078 2 5 3 74.16 20.70 1.13 9.57 3.55 0.36 1.97 111.45 5.71 6078 2 6 3 82.87 25.16 1.05 12.80 3.45 0.56 2.94 128.83 5.67 6078 2 7 3 76.64 22.56 0.85 11.80 2.99 0.48 2.42 117.74 5.76 6078 2 8 3 79.06 26.06 0.91 12.82 3.10 0.46 2.74 125.15 5.78 6078 2 9 3 76.13 25.61 0.87 12.38 3.35 0.44 2.78 121.56 5.81

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6162 2 11 2 75.51 30.32 0.95 11.82 2.28 0.49 3.64 125.00 5.87 6162 2 12 2 65.41 24.81 0.77 9.48 1.86 0.47 3.02 105.83 5.73 79 Table B-1. Continued IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------6078 2 12 3 67.82 21.68 0.69 10.14 2.57 0.33 2.11 105.34 5.52 6162 1 0 1 71.60 21.03 0.53 12.18 0.89 0.12 2.87 109.22 5.95 6162 1 1 1 79.68 26.59 0.65 14.65 1.00 0.21 2.83 125.61 6.09 6162 1 2 1 81.85 27.08 0.63 16.12 1.28 0.30 3.81 131.05 5.74 6162 1 3 1 89.28 26.91 0.86 13.21 1.75 0.38 2.96 135.36 5.95 6162 1 4 1 86.09 27.38 0.59 17.05 1.60 0.31 4.23 137.24 5.80 6162 1 5 1 77.14 25.63 0.57 15.86 1.54 0.30 3.90 124.94 5.92 6162 1 6 1 64.03 21.12 0.54 12.19 1.28 0.30 2.92 102.39 6.17 6162 1 7 1 64.82 21.87 0.53 13.55 1.22 0.28 3.24 105.51 6.22 6162 1 8 1 72.25 26.03 0.58 15.46 1.23 0.31 3.36 119.22 6.07 6162 1 9 1 60.59 21.48 0.56 12.64 1.09 0.25 2.89 99.50 6.44 6162 1 10 1 71.99 23.38 0.50 13.83 1.29 0.26 3.44 114.68 6.13 6162 1 11 1 71.36 28.68 0.64 16.43 1.36 0.28 3.62 122.37 5.98 6162 1 12 1 70.95 23.86 0.59 12.14 1.21 0.28 2.90 111.94 5.80 6162 2 0 2 59.08 21.45 0.69 9.26 1.62 0.46 2.52 95.07 6.03 6162 2 1 2 79.76 28.58 0.81 10.39 1.94 0.64 3.09 125.21 6.08 6162 2 2 2 78.27 28.07 0.88 11.04 2.17 0.63 3.30 124.36 6.06 6162 2 3 2 76.56 28.30 0.82 11.21 2.23 0.61 3.77 123.49 6.07 6162 2 4 2 78.51 28.29 0.81 11.05 2.27 0.56 3.68 125.18 5.93 6162 2 5 2 70.99 24.63 0.80 9.54 1.72 0.36 2.82 110.87 5.99 6162 2 6 2 72.22 23.01 0.82 9.13 1.80 0.38 3.04 110.39 5.79 6162 2 7 2 71.51 26.99 0.87 10.18 2.00 0.41 3.21 115.17 6.12 6162 2 8 2 66.99 25.51 0.78 9.57 1.97 0.44 3.16 108.43 6.02 6162 2 9 2 69.24 27.52 0.77 10.33 2.09 0.46 3.53 113.94 6.25 6162 2 10 2 78.73 30.50 0.88 11.92 2.26 0.54 3.92 128.75 5.92

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80 Table B-1. Continued IsoMethylIsoTotal Cow Period Hour Diet Acetate Propionate ButyrateButyrate Butyrate ValerateValerate VFA pH ----------------------------------------------------mM--------------------------------------------------------6162 3 0 4 70.45 20.79 0.80 10.58 1.76 0.36 2.69 107.44 6.21 6162 3 1 4 88.06 27.52 1.12 13.23 1.83 0.39 3.11 135.26 6.13 6162 3 2 4 84.53 28.18 1.09 14.47 1.84 0.41 3.57 134.09 6.04 6162 3 3 4 77.95 23.02 0.84 11.93 1.82 0.37 3.34 119.26 6.00 6162 3 4 4 71.51 21.82 0.69 12.13 1.62 0.26 3.29 111.31 5.84 6162 3 5 4 86.13 29.18 1.01 16.76 2.22 0.38 4.19 139.87 5.79 6162 3 6 4 85.87 27.55 0.82 14.73 1.77 0.31 2.63 133.68 5.71 6162 3 7 4 95.54 29.86 0.86 16.45 2.17 0.35 4.26 149.49 5.93 6162 3 8 4 80.76 27.93 0.76 14.16 1.60 0.32 3.62 129.15 5.87 6162 3 9 4 89.12 28.13 0.79 15.33 1.59 0.29 3.71 138.97 6.07 6162 3 10 4 96.85 30.33 0.88 16.69 1.83 0.31 4.04 150.93 5.86 6162 3 11 4 80.24 27.09 0.72 13.99 1.58 0.30 2.81 126.72 5.83 6162 3 12 4 67.19 22.98 0.64 11.43 1.28 0.23 2.55 106.30 6.06

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81 2682 3 6 6 4.54 3.15 2.81 2682 3 6 12 4.54 3.05 2.72 APPENDIX C IN SITU DEGRADATION OF SORGHUM SILAGE Table C-1. In situ degradation of sorghum silage by cow, period, diet, and hour of sampling. Diet 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP. Original Remaining Remaining Cow Period Diet Hour DM, g DM, g NDF, g 2682 1 2 0 4.54 3.50 3.16 2682 1 2 0 4.54 3.52 3.14 2682 1 2 0 4.53 3.52 3.21 2682 1 2 6 4.53 3.24 2.88 2682 1 2 6 4.54 3.26 2.90 2682 1 2 12 4.54 2.99 2.67 2682 1 2 12 4.54 3.00 2.69 2682 1 2 18 4.53 2.79 2.52 2682 1 2 18 4.54 2.71 2.43 2682 1 2 24 4.53 2.57 2.30 2682 1 2 24 4.54 2.61 2.30 2682 1 2 30 4.53 2.31 2.04 2682 1 2 30 4.54 2.27 2.02 2682 1 2 48 4.54 2.02 1.81 2682 1 2 48 4.54 1.99 1.75 2682 2 3 0 4.54 3.47 2.93 2682 2 3 0 4.54 3.47 2.94 2682 2 3 0 4.54 --2682 2 3 6 4.54 3.24 2.87 2682 2 3 6 4.54 3.23 2.87 2682 2 3 12 4.54 2.94 2.63 2682 2 3 12 4.54 --2682 2 3 18 4.54 2.62 2.35 2682 2 3 18 4.54 2.67 2.36 2682 2 3 24 4.54 2.68 2.40 2682 2 3 24 4.54 2.85 2.53 2682 2 3 30 4.54 2.30 2.03 2682 2 3 30 4.54 2.49 2.22 2682 2 3 48 4.54 2.14 1.89 2682 2 3 48 4.54 2.05 1.80 2682 3 6 0 4.54 3.39 2.95 2682 3 6 0 4.54 3.38 2.91 2682 3 6 0 4.54 3.40 2.95 2682 3 6 6 4.54 3.21 2.85

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82 Table C-1. Continued Original Remaining Remaining Cow Period Diet Hour DM, g DM, g NDF, g 2682 3 6 12 4.54 3.06 2.72 2824 3 3 12 4.54 3.08 2.76 2824 3 3 12 4.54 3.04 2.71 2682 3 6 18 4.54 2.97 2.64 2682 3 6 18 4.54 2.91 2.61 2682 3 6 24 4.54 2.73 2.46 2682 3 6 24 4.54 2.84 2.55 2682 3 6 30 4.54 2.56 2.31 2682 3 6 30 4.54 2.63 2.37 2682 3 6 48 4.54 2.15 1.90 2682 3 6 48 4.54 2.32 2.06 2824 1 5 0 4.54 3.50 3.16 2824 1 5 0 4.54 3.52 3.14 2824 1 5 0 4.53 3.52 3.21 2824 1 5 6 4.54 3.28 2.94 2824 1 5 6 4.54 3.29 2.94 2824 1 5 12 4.54 3.02 2.74 2824 1 5 12 4.54 3.13 2.80 2824 1 5 18 4.54 2.95 2.68 2824 1 5 18 4.54 2.98 2.70 2824 1 5 24 4.54 2.85 2.58 2824 1 5 24 4.54 2.83 2.54 2824 1 5 30 4.54 2.71 2.44 2824 1 5 30 4.54 2.58 2.34 2824 1 5 48 4.54 2.11 1.83 2824 1 5 48 4.54 2.22 1.91 2824 2 6 0 4.54 3.47 2.93 2824 2 6 0 4.54 3.47 2.94 2824 2 6 0 4.54 --2824 2 6 6 4.54 3.20 2.85 2824 2 6 6 4.54 --2824 2 6 12 4.54 2.89 2.58 2824 2 6 12 4.53 2.95 2.66 2824 2 6 18 4.54 2.88 2.61 2824 2 6 18 4.54 2.88 2.61 2824 2 6 24 4.54 2.60 2.32 2824 2 6 24 4.54 --2824 2 6 30 4.54 2.47 2.23 2824 2 6 30 4.54 2.44 2.16 2824 2 6 48 4.54 2.16 1.93 2824 2 6 48 4.54 2.20 1.95 2824 3 3 0 4.54 3.39 2.95 2824 3 3 0 4.54 3.38 2.91 2824 3 3 0 4.54 3.40 2.95 2824 3 3 6 4.54 3.26 2.89 2824 3 3 6 4.54 3.21 2.88

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83 Table C-1. Continued Original Remaining Remaining Cow Period Diet Hour DM, g DM, g NDF, g 2824 3 3 18 4.54 2.79 2.50 3755 3 1 12 4.54 3.05 2.74 3755 3 1 18 4.54 2.84 2.54 2824 3 3 18 4.54 2.77 2.47 2824 3 3 24 4.54 2.86 2.56 2824 3 3 24 4.54 2.83 2.52 2824 3 3 30 4.54 2.42 2.17 2824 3 3 30 4.54 2.39 2.11 2824 3 3 48 4.54 2.08 1.83 2824 3 3 48 4.54 2.04 1.79 3755 1 3 0 4.54 3.50 3.16 3755 1 3 0 4.54 3.52 3.14 3755 1 3 0 4.53 3.52 3.21 3755 1 3 6 4.54 3.14 2.81 3755 1 3 6 4.54 3.24 2.83 3755 1 3 12 4.54 3.02 2.69 3755 1 3 12 4.54 2.99 2.66 3755 1 3 18 4.53 2.76 2.47 3755 1 3 18 4.54 2.78 2.47 3755 1 3 24 4.54 2.42 2.16 3755 1 3 24 4.54 2.47 2.18 3755 1 3 30 4.54 2.20 1.92 3755 1 3 30 4.54 2.16 1.89 3755 1 3 48 4.54 1.82 1.57 3755 1 3 48 4.54 1.87 1.62 3755 2 4 0 4.54 3.47 2.93 3755 2 4 0 4.54 3.47 2.94 3755 2 4 0 4.54 --3755 2 4 6 4.54 3.20 2.84 3755 2 4 6 4.54 3.25 2.88 3755 2 4 12 4.54 2.91 2.60 3755 2 4 12 4.54 2.88 2.59 3755 2 4 18 4.53 2.73 2.47 3755 2 4 18 4.54 2.81 2.54 3755 2 4 24 4.54 2.65 2.38 3755 2 4 24 4.54 2.52 2.29 3755 2 4 30 4.54 2.29 2.07 3755 2 4 30 4.54 2.49 2.24 3755 2 4 48 4.54 1.93 1.68 3755 2 4 48 4.54 2.12 1.85 3755 3 1 0 4.54 3.39 2.95 3755 3 1 0 4.54 3.38 2.91 3755 3 1 0 4.54 3.40 2.95 3755 3 1 6 4.54 3.28 2.89 3755 3 1 6 4.54 3.23 2.84 3755 3 1 12 4.54 3.00 2.66

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84 Table C-1. Continued Original Remaining Remaining Cow Period Diet Hour DM, g DM, g NDF, g 3755 3 1 18 4.54 2.84 2.55 5896 3 2 18 4.54 2.49 2.25 5896 3 2 18 4.54 2.51 2.26 3755 3 1 24 4.54 2.64 2.38 3755 3 1 24 4.54 2.60 2.36 3755 3 1 30 4.54 2.39 2.15 3755 3 1 30 4.54 2.51 2.27 3755 3 1 48 4.54 2.02 1.79 3755 3 1 48 4.54 1.93 1.71 5896 1 4 0 4.54 3.50 3.16 5896 1 4 0 4.54 3.52 3.14 5896 1 4 0 4.53 3.52 3.21 5896 1 4 6 4.54 3.20 2.86 5896 1 4 6 4.54 3.13 2.79 5896 1 4 12 4.54 2.89 2.61 5896 1 4 12 4.54 2.99 2.69 5896 1 4 18 4.54 2.64 2.36 5896 1 4 18 4.54 2.63 2.32 5896 1 4 24 4.53 2.46 2.21 5896 1 4 24 4.53 2.41 2.17 5896 1 4 30 4.54 2.40 2.12 5896 1 4 30 4.54 2.16 1.92 5896 1 4 48 4.54 1.81 1.61 5896 1 4 48 4.54 1.88 1.59 5896 2 5 0 4.54 3.47 2.93 5896 2 5 0 4.54 3.47 2.94 5896 2 5 0 4.54 --5896 2 5 6 4.54 3.09 2.73 5896 2 5 6 4.54 3.12 2.77 5896 2 5 12 4.53 2.87 2.59 5896 2 5 12 4.54 2.88 2.60 5896 2 5 18 4.53 2.69 2.40 5896 2 5 18 4.54 2.78 2.52 5896 2 5 24 4.54 2.57 2.31 5896 2 5 24 4.53 2.56 2.29 5896 2 5 30 4.54 2.49 2.21 5896 2 5 30 4.54 2.31 2.03 5896 2 5 48 4.54 1.93 1.69 5896 2 5 48 4.54 1.91 1.69 5896 3 2 0 4.54 3.39 2.95 5896 3 2 0 4.54 3.38 2.91 5896 3 2 0 4.54 3.40 2.95 5896 3 2 6 4.54 3.05 2.74 5896 3 2 6 4.54 3.10 2.78 5896 3 2 12 4.54 2.77 2.51 5896 3 2 12 4.54 2.67 2.43

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85 Table C-1. Continued Original Remaining Remaining Cow Period Diet Hour DM, g DM, g NDF, g 5896 3 2 24 4.54 2.27 2.03 6162 1 6 18 4.54 2.87 2.56 6162 1 6 24 4.54 2.65 2.37 5896 3 2 24 4.54 2.23 2.00 5896 3 2 30 4.54 2.16 1.95 5896 3 2 30 4.54 2.21 1.98 5896 3 2 48 4.54 1.74 1.53 5896 3 2 48 4.54 1.77 1.56 6078 1 1 0 4.54 3.50 3.16 6078 1 1 0 4.54 3.52 3.14 6078 1 1 0 4.53 3.52 3.21 6078 1 1 6 4.54 3.27 2.88 6078 1 1 6 4.54 3.25 2.90 6078 1 1 12 4.53 3.18 2.85 6078 1 1 12 4.54 3.08 2.75 6078 1 1 18 4.54 2.97 2.68 6078 1 1 18 4.53 3.00 2.72 6078 1 1 24 4.54 2.79 2.50 6078 1 1 24 4.54 2.88 2.57 6078 1 1 30 4.54 2.60 2.34 6078 1 1 30 4.54 2.58 2.30 6078 1 1 48 4.54 2.02 1.78 6078 1 1 48 4.54 --6078 2 1 0 4.54 3.47 2.93 6078 2 2 0 4.54 3.47 2.94 6078 2 2 0 4.54 --6078 2 2 6 4.54 3.27 2.87 6078 2 2 6 4.54 3.33 2.94 6078 2 2 12 4.54 3.01 2.69 6078 2 2 12 4.54 2.82 2.51 6078 2 2 18 4.54 2.81 2.52 6078 2 2 18 4.54 2.69 2.41 6078 2 2 24 4.54 2.83 2.51 6078 2 2 24 4.54 2.58 2.30 6078 2 2 30 4.54 2.44 2.17 6078 2 2 30 4.54 2.43 2.16 6078 2 2 48 4.54 2.22 1.97 6078 2 2 48 4.53 2.09 1.85 6162 1 6 0 4.54 3.50 3.16 6162 1 6 0 4.54 3.52 3.14 6162 1 6 0 4.53 3.52 3.21 6162 1 6 6 4.54 3.11 2.73 6162 1 6 6 4.53 3.13 2.74 6162 1 6 12 4.54 2.90 2.60 6162 1 6 12 4.54 2.85 2.56 6162 1 6 18 4.54 2.73 2.44

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86 Table C-1. Continued Original Remaining Remaining Cow Period Diet Hour DM, g DM, g NDF, g 6162 1 6 24 4.54 2.53 2.24 6162 1 6 30 4.54 2.26 2.02 6162 1 6 30 4.54 2.29 2.04 6162 1 6 48 4.54 2.02 1.75 6162 1 6 48 4.54 1.86 1.66 6162 2 1 0 4.54 3.47 2.93 6162 2 1 0 4.54 3.47 2.94 6162 2 1 0 4.54 --6162 2 1 6 4.54 3.12 2.78 6162 2 1 6 4.54 3.13 2.76 6162 2 1 12 4.54 2.92 2.62 6162 2 1 12 4.54 2.92 2.59 6162 2 1 18 4.54 2.73 2.42 6162 2 1 18 4.54 --6162 2 1 24 4.54 2.63 2.36 6162 2 1 24 4.54 2.63 2.35 6162 2 1 30 4.54 2.37 2.12 6162 2 1 30 4.54 2.28 2.04 6162 2 1 48 4.54 2.16 1.89 6162 2 1 48 4.54 2.16 1.90 6162 3 4 0 4.54 3.39 2.95 6162 3 4 0 4.54 3.38 2.91 6162 3 4 0 4.54 3.40 2.95 6162 3 4 6 4.54 3.19 2.83 6162 3 4 6 4.54 3.15 2.82 6162 3 4 12 4.54 2.94 2.59 6162 3 4 12 4.54 2.94 2.64 6162 3 4 18 4.54 2.85 2.58 6162 3 4 18 4.54 2.77 2.50 6162 3 4 24 4.54 2.65 2.38 6162 3 4 24 4.54 2.55 2.26 6162 3 4 30 4.54 2.51 2.21 6162 3 4 30 4.54 2.39 2.12 6162 3 4 48 4.54 1.98 1.74 6162 3 4 48 4.54 --

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APPENDIX D NUTRIENT INTAKES

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88 Table D-1. Offered feed and nutrients by cow, period and diet. Diet 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP. Offered, Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d DM -----------------------------------% of DM---------------------------------2680 1 3 27.2 0.46 0.07 0.14 0.40 0.10 0.16 0.06 2682 1 2 25.6 0.45 0.07 0.16 0.39 0.05 0.25 0.02 2760 1 6 33.0 0.47 0.07 0.17 0.37 0.16 0.14 0.04 2824 1 5 25.4 0.48 0.07 0.18 0.37 0.13 0.13 0.06 2931 1 6 29.7 0.46 0.07 0.17 0.39 0.16 0.14 0.03 2986 1 2 28.8 0.42 0.06 0.16 0.40 0.05 0.25 0.01 3136 1 3 30.1 0.47 0.07 0.15 0.41 0.09 0.16 0.05 3165 1 2 25.6 0.45 0.06 0.17 0.40 0.05 0.25 0.02 3319 1 1 27.0 0.45 0.06 0.16 0.40 0.05 0.25 0.02 3338 1 6 24.8 0.47 0.07 0.17 0.40 0.14 0.14 -3340 1 5 25.6 0.48 0.07 0.18 0.40 0.14 0.13 0.03 3344 1 5 29.5 0.47 0.08 0.17 0.40 0.13 0.15 0.02 3444 1 2 28.8 0.45 0.06 0.16 0.40 0.05 0.23 0.04 3445 1 6 32.7 0.47 0.07 0.18 0.39 0.14 0.13 0.05 3448 1 4 28.8 0.44 0.06 0.16 0.43 0.08 0.16 0.03 3532 1 3 29.3 0.47 0.06 0.17 0.38 0.08 0.16 0.08 3560 1 4 29.9 0.48 0.06 0.17 0.38 0.08 0.17 0.08 3588 1 5 28.2 0.46 0.07 0.16 0.43 0.14 0.15 -3621 1 1 29.7 0.44 0.07 0.17 0.39 0.04 0.21 0.05 3622 1 4 29.1 0.46 0.06 0.16 0.38 0.08 0.15 0.08

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3338 2 4 29.7 0.47 0.07 0.17 0.41 0.07 0.13 0.07 3340 2 3 25.4 0.44 0.07 0.17 0.41 0.06 0.15 0.06 89 Table D-1. Continued Offered, Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d DM ------------------------------------% of DM---------------------------------3633 1 3 26.1 0.48 0.06 0.17 0.40 0.08 0.16 0.05 3661 1 2 25.1 0.45 0.07 0.16 0.39 0.04 0.26 -3668 1 1 24.9 0.44 0.06 0.16 0.38 0.05 0.23 -3703 1 2 28.2 0.45 0.06 0.15 0.36 0.05 0.22 0.04 3708 1 4 24.1 0.49 0.06 0.16 0.38 0.07 0.17 0.03 3738 1 4 24.3 0.46 0.06 0.17 0.41 0.08 0.15 0.01 3755 1 3 25.0 0.46 0.06 0.17 0.41 0.09 0.12 0.05 3801 1 1 24.5 0.46 0.07 0.17 0.41 0.04 0.23 0.00 5882 1 5 28.2 0.45 0.07 0.18 0.39 0.13 0.13 0.06 5896 1 4 24.7 0.44 0.06 0.16 0.40 0.07 0.16 0.06 6000 1 1 28.7 0.45 0.06 0.17 0.39 0.04 0.24 0.00 6029 1 4 28.7 0.50 0.06 0.16 0.37 0.08 0.18 0.03 6072 1 3 28.6 0.47 0.07 0.16 0.41 0.08 0.17 0.02 6078 1 1 25.7 0.46 0.06 0.18 0.38 0.05 0.24 -6079 1 2 27.9 0.42 0.06 0.18 0.39 0.04 0.25 0.00 6095 1 6 32.3 0.44 0.07 0.18 0.40 0.14 0.14 0.04 6138 1 3 26.3 0.42 0.07 0.17 0.40 0.07 0.18 0.05 6162 1 6 32.5 0.48 0.07 0.16 0.39 0.14 0.09 0.11 2680 2 2 30.6 0.47 0.07 0.16 0.39 0.04 0.23 0.04 2682 2 3 25.9 0.47 0.07 0.17 0.40 0.08 0.16 0.05 2760 2 3 32.8 0.45 0.07 0.18 0.39 0.08 0.15 0.07 2824 2 6 26.5 0.47 0.07 0.17 0.39 0.14 0.13 0.03 2931 2 5 35.2 0.50 0.07 0.17 0.35 0.13 0.14 0.06 2986 2 5 34.0 0.47 0.07 0.18 0.38 0.13 0.13 0.06 3136 2 5 31.1 0.47 0.07 0.18 0.39 0.13 0.13 0.07 3165 2 4 29.6 0.46 0.07 0.17 0.40 0.08 0.13 0.07 3319 2 3 28.5 0.46 0.07 0.17 0.40 0.07 0.16 0.07

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2680 3 3 26.4 0.47 0.07 0.15 0.42 0.07 0.14 0.05 2682 3 6 26.9 0.49 0.07 0.16 0.39 0.13 0.13 0.02 90 Table D-1. Continued Offered, Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d DM -----------------------------------% of DM----------------------------------3344 2 1 28.1 0.46 0.07 0.17 0.37 0.04 0.24 0.04 3444 2 1 27.2 0.44 0.06 0.18 0.37 0.04 0.24 0.05 3445 2 6 33.9 0.47 0.07 0.18 0.39 0.12 0.12 0.04 3448 2 1 32.3 0.46 0.07 0.18 0.43 0.04 0.24 -3532 2 1 27.9 0.46 0.07 0.18 0.37 0.05 0.23 0.05 3560 2 2 31.6 0.45 0.07 0.16 0.39 0.04 0.23 0.04 3588 2 5 27.6 0.46 0.07 0.18 0.38 0.13 0.13 0.05 3621 2 5 32.1 0.48 0.07 0.18 0.38 0.13 0.13 0.05 3622 2 6 27.5 0.45 0.08 0.17 0.38 0.14 0.12 0.05 3633 2 6 27.8 0.47 0.07 0.14 0.38 0.14 0.13 0.03 3661 2 6 27.2 0.46 0.07 0.16 0.38 0.13 0.12 0.08 3668 2 1 26.9 0.47 0.06 0.17 0.39 0.05 0.23 0.00 3703 2 2 32.2 0.47 0.06 0.15 0.38 0.04 0.24 0.02 3708 2 4 26.3 0.48 0.07 0.17 0.40 0.07 0.13 0.07 3738 2 5 29.0 0.48 0.07 0.17 0.37 0.13 0.12 0.04 3755 2 4 31.4 0.48 0.07 0.16 0.39 0.08 0.15 0.05 3801 2 6 25.9 0.47 0.07 0.17 0.40 0.13 0.13 0.02 5882 2 2 29.9 0.47 0.05 0.17 0.42 0.04 0.23 0.02 5896 2 5 26.4 0.49 0.06 0.17 0.37 0.14 0.15 0.02 6000 2 4 27.5 0.42 0.07 0.17 0.41 0.07 0.14 0.06 6029 2 3 28.0 0.45 0.06 0.17 0.43 0.07 0.15 0.05 6072 2 4 33.1 0.46 0.07 0.16 0.39 0.07 0.15 0.05 6078 2 2 24.8 0.45 0.07 0.16 0.39 0.04 0.24 0.02 6079 2 3 31.4 0.46 0.07 0.14 0.38 0.08 0.14 0.06 6095 2 2 35.4 0.48 0.07 0.14 0.39 0.04 0.23 0.03 6138 2 3 27.2 0.45 0.07 0.17 0.39 0.07 0.16 0.06 6162 2 1 33.8 0.47 0.06 0.17 0.39 0.04 0.22 0.04

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5896 3 2 24.4 0.45 0.06 0.15 0.36 0.04 0.23 0.06 91 Table D-1. Continued Offered, Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d DM -----------------------------------% of DM----------------------------------2760 3 2 36.7 0.47 0.06 0.15 0.45 0.05 0.23 -2824 3 3 24.6 0.48 0.07 0.16 0.42 0.07 0.13 0.06 2931 3 6 32.3 0.47 0.06 0.16 0.39 0.12 0.13 0.04 2986 3 4 30.7 0.48 0.06 0.15 0.43 0.05 0.15 0.05 3136 3 3 23.5 0.47 0.07 0.15 0.43 0.07 0.13 0.05 3165 3 2 30.2 0.49 0.06 0.14 0.40 0.05 0.23 0.02 3319 3 1 29.8 0.46 0.06 0.14 0.39 0.05 0.24 0.02 3338 3 4 22.9 0.47 0.06 0.14 0.41 0.08 0.14 0.06 3340 3 3 24.3 0.46 0.07 0.14 0.43 0.07 0.13 0.05 3344 3 5 27.1 0.48 0.07 0.15 0.38 0.13 0.13 0.03 3444 3 2 32.1 0.49 0.06 0.15 0.41 0.04 0.22 0.03 3445 3 2 37.3 0.46 0.06 0.15 0.40 0.04 0.23 0.03 3448 3 6 29.1 0.45 0.07 0.16 0.38 0.13 0.14 0.02 3532 3 1 27.9 0.46 0.07 0.15 0.39 0.04 0.23 0.03 3560 3 2 29.7 0.44 0.06 0.15 0.42 0.04 0.23 0.01 3588 3 1 27.8 0.45 0.06 0.15 0.40 0.04 0.23 0.02 3621 3 5 31.9 0.47 0.07 0.16 0.39 0.13 0.13 0.02 3622 3 4 24.9 0.50 0.07 0.16 0.42 0.07 0.13 0.08 3633 3 5 25.7 0.47 0.07 0.17 0.39 0.13 0.13 0.04 3661 3 6 28.0 0.46 0.07 0.17 0.40 0.13 0.14 0.01 3668 3 3 24.4 0.46 0.07 0.17 0.41 0.07 0.13 0.05 3703 3 4 22.4 0.47 0.06 0.17 0.41 0.07 0.13 0.05 3708 3 6 22.4 0.50 0.07 0.17 0.40 0.13 0.13 0.01 3738 3 2 28.6 0.45 0.06 0.16 0.39 0.04 0.24 0.02 3755 3 1 29.6 0.46 0.07 0.16 0.39 0.04 0.23 0.02 3801 3 1 24.5 0.44 0.06 0.15 0.42 0.03 0.23 -5882 3 1 27.6 0.46 0.06 0.14 0.40 0.04 0.24 0.01

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92 Table D-1. Continued Offered, Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d DM -----------------------------------% of DM----------------------------------6000 3 3 23.6 0.47 0.07 0.17 0.42 0.06 0.13 0.06 6029 3 4 28.2 0.48 0.07 0.16 0.43 0.06 0.14 0.04 6072 3 1 30.1 0.47 0.07 0.15 0.37 0.04 0.24 0.02 6079 3 6 29.3 0.46 0.07 0.16 0.40 0.12 0.13 0.01 6095 3 6 33.1 0.46 0.07 0.16 0.41 0.12 0.13 0.00 6138 3 5 28.4 0.46 0.07 0.15 0.39 0.12 0.13 0.02 6162 3 4 27.7 0.46 0.07 0.15 0.42 0.06 0.14 0.03

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3738 1 4 1.22 0.47 0.06 0.15 0.42 0.08 0.14 0.02 93 Table D-2. Refused feed and nutrients by cow, period and diet. Diet 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP. Refusal, Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d DM ------------------------------------------% of DM------------------------------------------2680 1 3 1.79 0.43 0.06 0.13 0.39 0.09 0.19 0.06 2682 1 2 4.43 0.44 0.06 0.15 0.40 0.05 0.27 0.01 2760 1 6 1.08 0.48 0.07 0.16 0.38 0.14 0.16 0.03 2824 1 5 2.36 0.46 0.07 0.15 0.37 0.17 0.15 0.06 2931 1 6 1.94 0.47 0.06 0.14 0.41 0.15 0.15 0.02 2986 1 2 2.91 0.44 0.06 0.15 0.43 0.04 0.23 0.00 3136 1 3 1.91 0.44 0.06 0.15 0.43 0.09 0.18 0.01 3165 1 2 0.30 0.36 0.05 0.14 0.41 0.05 0.23 0.03 3319 1 1 3.75 0.45 0.07 0.16 0.40 0.04 0.28 0.01 3338 1 6 1.98 0.43 0.06 0.15 0.41 0.15 0.16 -3340 1 5 3.16 0.43 0.06 0.14 0.38 0.15 0.16 0.03 3344 1 5 4.18 0.47 0.07 0.16 0.38 0.15 0.15 0.03 3444 1 2 3.56 0.40 0.06 0.15 0.42 0.04 0.23 0.02 3445 1 6 2.80 0.43 0.07 0.16 0.40 0.12 0.14 0.03 3448 1 4 4.46 0.41 0.06 0.15 0.39 0.08 0.19 0.04 3532 1 3 1.46 0.49 0.06 0.14 0.39 0.07 0.17 0.06 3560 1 4 3.22 0.43 0.06 0.14 0.44 0.07 0.15 0.02 3588 1 5 2.39 0.44 0.06 0.14 0.40 0.12 0.16 0.01 3621 1 1 2.86 0.38 0.06 0.14 0.38 0.04 0.21 0.08 3622 1 4 5.80 0.44 0.06 0.15 0.40 0.08 0.17 0.05 3633 1 3 1.79 0.40 0.06 0.15 0.43 0.07 0.17 0.04 3661 1 2 1.84 0.46 0.06 0.14 0.43 0.04 0.22 -3668 1 1 2.17 0.35 0.06 0.16 0.36 0.04 0.26 0.02 3703 1 2 2.66 0.43 0.06 0.15 0.42 0.05 0.21 -3708 1 4 2.91 0.46 0.06 0.15 0.38 0.08 0.16 0.03

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3532 2 1 5.87 0.44 0.06 0.15 0.42 0.04 0.22 0.00 3560 2 2 7.25 0.43 0.06 0.15 0.45 0.04 0.22 -94 Table D-2. Continued Refusal, Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d DM ----------------------------------------% of DM---------------------------------------3755 1 3 3.70 0.51 0.06 0.14 0.40 0.09 0.13 0.05 3801 1 1 1.21 0.35 0.06 0.15 0.49 0.03 0.19 -5882 1 5 1.75 0.45 0.07 0.15 0.41 0.14 0.13 0.04 5896 1 4 2.32 0.46 0.06 0.15 0.42 0.07 0.16 0.06 6000 1 1 1.95 0.42 0.06 0.15 0.41 0.04 0.24 -6029 1 4 1.22 0.44 0.06 0.14 0.42 0.07 0.14 0.03 6072 1 3 1.85 0.44 0.06 0.14 0.42 0.08 0.17 0.04 6078 1 1 0.85 0.32 0.06 0.14 0.40 0.04 0.20 0.04 6079 1 2 2.17 0.42 0.06 0.14 0.41 0.04 0.22 0.00 6095 1 6 2.77 0.45 0.06 0.16 0.42 0.12 0.14 0.03 6138 1 3 1.96 0.41 0.06 0.14 0.42 0.07 0.18 0.01 6162 1 6 2.05 0.44 0.06 0.15 0.40 0.12 0.10 0.08 2680 2 2 5.30 0.46 0.07 0.16 0.41 0.04 0.23 0.00 2682 2 3 6.07 0.46 0.07 0.16 0.39 0.09 0.14 0.08 2760 2 3 0.86 0.46 0.06 0.15 0.43 0.07 0.14 0.04 2824 2 6 3.96 0.48 0.06 0.16 0.42 0.11 0.14 0.01 2931 2 5 6.10 0.48 0.07 0.16 0.38 0.13 0.14 0.04 2986 2 5 4.78 0.48 0.06 0.15 0.39 0.11 0.12 0.06 3136 2 5 4.40 0.47 0.07 0.16 0.39 0.12 0.14 0.05 3165 2 4 2.49 0.43 0.06 0.14 0.43 0.07 0.16 0.01 3319 2 3 2.59 0.47 0.06 0.15 0.39 0.07 0.15 0.09 3338 2 4 5.17 0.44 0.06 0.15 0.43 0.07 0.14 0.04 3340 2 3 4.55 0.44 0.06 0.15 0.43 0.06 0.15 0.02 3344 2 1 3.41 0.42 0.06 0.16 0.45 0.03 0.23 -3444 2 1 6.60 0.42 0.06 0.14 0.39 0.04 0.24 0.02 3445 2 6 2.02 0.45 0.07 0.15 0.43 0.12 0.13 0.02 3448 2 1 2.72 0.44 0.06 0.16 0.31 0.04 0.24 0.12

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3165 3 2 4.77 0.44 0.06 0.14 0.43 0.04 0.22 0.00 95Table D-2. Continued Refusal, Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d DM -----------------------------------------% of DM----------------------------------------3588 2 5 3.94 0.46 0.07 0.16 0.39 0.13 0.13 0.04 3621 2 5 2.41 0.38 0.07 0.14 0.41 0.12 0.14 0.02 3622 2 6 5.96 0.45 0.06 0.16 0.38 0.13 0.14 0.06 3633 2 6 1.59 0.43 0.06 0.17 0.43 0.11 0.14 0.00 3661 2 6 2.36 0.46 0.07 0.13 0.35 0.11 0.14 0.09 3668 2 1 3.94 0.45 0.06 0.14 0.44 0.03 0.23 -3703 2 2 4.14 0.42 0.06 0.14 0.43 0.03 0.23 -3708 2 4 4.04 0.48 0.07 0.16 0.39 0.07 0.14 0.07 3738 2 5 1.58 0.46 0.06 0.15 0.41 0.12 0.13 0.02 3755 2 4 5.91 0.48 0.07 0.17 0.40 0.08 0.15 0.05 3801 2 6 2.71 0.46 0.07 0.15 0.43 0.12 0.13 0.00 5882 2 2 4.82 0.44 0.06 0.15 0.43 0.04 0.22 0.01 5896 2 5 4.83 0.47 0.07 0.16 0.37 0.13 0.14 0.03 6000 2 4 4.95 0.47 0.06 0.16 0.42 0.08 0.13 0.07 6029 2 3 2.07 0.43 0.06 0.15 0.42 0.07 0.15 0.05 6072 2 4 8.29 0.44 0.06 0.15 0.41 0.08 0.14 0.03 6078 2 2 6.78 0.43 0.06 0.15 0.38 0.05 0.22 0.06 6079 2 3 4.65 0.45 0.06 0.14 0.38 0.08 0.15 0.06 6095 2 2 2.00 0.44 0.06 0.14 0.38 0.04 0.22 0.04 6138 2 3 2.00 0.45 0.06 0.14 0.43 0.07 0.14 0.03 6162 2 1 3.19 0.42 0.06 0.15 0.43 0.04 0.21 0.01 2680 3 3 3.81 0.47 0.06 0.15 0.40 0.07 0.13 0.08 2682 3 6 6.57 0.48 0.07 0.15 0.38 0.14 0.14 0.02 2760 3 2 4.43 0.49 0.06 0.13 0.44 0.05 0.21 0.02 2824 3 3 3.57 0.47 0.06 0.15 0.40 0.07 0.15 0.09 2931 3 6 3.92 0.50 0.06 0.15 0.39 0.12 0.14 0.04 2986 3 4 8.61 0.46 0.07 0.14 0.43 0.05 0.16 0.04 3136 3 3 2.99 0.44 0.06 0.13 0.42 0.07 0.15 0.05

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6162 3 4 3.47 0.47 0.06 0.14 0.38 0.07 0.14 0.08 96Table D-2. Continued Refusal, DM Ash CP NDF Sugar Starch NDSF Cow Period Diet kg/d ----------------------------------------% of DM---------------------------------------3319 3 1 6.69 0.48 0.06 0.14 0.39 0.04 0.24 0.03 3338 3 4 6.18 0.51 0.07 0.14 0.41 0.08 0.14 0.07 3340 3 3 7.02 0.49 0.06 0.13 0.45 0.08 0.14 0.02 3344 3 5 6.70 0.47 0.07 0.15 0.40 0.13 0.13 0.02 3444 3 2 5.98 0.45 0.06 0.13 0.45 0.03 0.23 -3445 3 2 5.17 0.47 0.06 0.14 0.42 0.04 0.22 0.02 3448 3 6 7.02 0.49 0.06 0.14 0.39 0.12 0.15 0.02 3532 3 1 3.83 0.43 0.06 0.13 0.47 0.03 0.21 -3560 3 2 5.69 0.46 0.06 0.14 0.43 0.04 0.21 -3588 3 1 3.88 0.43 0.06 0.14 0.43 0.04 0.23 -3621 3 5 5.06 0.46 0.06 0.14 0.45 0.12 0.14 -3622 3 4 5.85 0.48 0.06 0.16 0.45 0.07 0.14 0.04 3633 3 5 2.90 0.42 0.06 0.14 0.43 0.12 0.14 0.00 3661 3 6 4.98 0.47 0.07 0.15 0.39 0.13 0.14 0.02 3668 3 3 4.42 0.46 0.07 0.16 0.38 0.07 0.14 0.07 3703 3 4 4.78 0.46 0.06 0.16 0.40 0.07 0.14 0.06 3708 3 6 6.05 0.49 0.07 0.16 0.38 0.12 0.15 0.01 3738 3 2 3.81 0.47 0.07 0.14 0.43 0.04 0.22 -3755 3 1 5.02 0.47 0.07 0.16 0.37 0.03 0.22 0.04 3801 3 1 3.50 0.38 0.06 0.14 0.41 0.03 0.23 0.00 5882 3 1 4.03 0.44 0.06 0.15 0.43 0.04 0.22 -5896 3 2 4.25 0.45 0.06 0.15 0.39 0.04 0.22 0.03 6000 3 3 3.72 0.42 0.07 0.16 0.40 0.07 0.14 0.06 6029 3 4 4.04 0.46 0.06 0.15 0.42 0.07 0.15 0.04 6072 3 1 5.14 0.46 0.06 0.15 0.41 0.04 0.23 -6079 3 6 3.63 0.48 0.06 0.13 0.42 0.11 0.14 -6095 3 6 6.12 0.47 0.06 0.14 0.32 0.11 0.13 0.11 6138 3 5 4.64 0.46 0.07 0.15 0.40 0.12 0.14 0.01

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3738 1 4 23.1 1.50 3.87 9.44 1.78 3.51 0.29 97 Table D-3. Intake of feed and nutrients by cow, period and diet. Diet 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP. DMI Ash CP NDF Sugar Starch NDSF Cow Period Diet ----------------------------------------------------kg/d ---------------------------------------------------2680 1 3 25.4 1.67 3.65 10.24 2.50 4.15 1.47 2682 1 2 21.2 1.47 3.46 8.26 1.12 5.14 0.44 2760 1 6 31.9 2.33 5.29 11.73 5.12 4.55 1.36 2824 1 5 23.0 1.66 4.10 8.64 2.81 3.00 1.39 2931 1 6 27.7 1.91 4.74 10.78 4.39 3.76 0.97 2986 1 2 25.9 1.59 4.05 10.39 1.19 6.41 0.33 3136 1 3 28.2 2.03 4.30 11.66 2.47 4.35 1.55 3165 1 2 25.3 1.57 4.20 10.10 1.20 6.29 0.61 3319 1 1 23.2 1.45 3.84 9.16 1.09 5.59 0.64 3338 1 6 22.9 1.64 3.90 9.20 3.13 3.26 -3340 1 5 22.5 1.71 4.10 9.02 3.24 2.93 0.64 3344 1 5 25.4 2.02 4.45 10.18 3.13 3.76 0.40 3444 1 2 25.2 1.54 4.05 10.14 1.25 5.90 0.99 3445 1 6 29.9 1.97 5.40 11.51 4.24 3.77 1.57 3448 1 4 24.4 1.60 3.97 10.58 1.85 3.64 0.64 3532 1 3 27.8 1.68 4.76 10.51 2.13 4.49 2.38 3560 1 4 26.7 1.70 4.72 10.01 2.23 4.47 2.26 3588 1 5 25.8 1.80 4.27 11.08 3.54 3.86 -3621 1 1 26.8 1.82 4.60 10.49 1.06 5.72 1.30 3622 1 4 23.3 1.50 3.67 8.77 1.86 3.34 2.02 3633 1 3 24.3 1.56 4.16 9.72 1.97 3.89 1.15 3661 1 2 23.2 1.53 3.85 8.94 0.93 6.01 -3668 1 1 22.7 1.41 3.60 8.69 1.04 5.12 -3703 1 2 25.5 1.64 3.97 9.05 1.41 5.57 1.02 3708 1 4 21.1 1.30 3.40 8.00 1.56 3.59 0.66

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3532 2 1 22.1 1.54 4.17 7.79 1.01 5.13 1.39 3560 2 2 24.3 1.71 3.97 8.98 1.07 5.75 1.32 98 Table D-3. Continued DMI Ash CP NDF Sugar Starch NDSF Cow Period Diet ----------------------------------------------------kg/d ---------------------------------------------------3755 1 3 21.3 1.27 3.63 8.89 1.81 2.39 0.95 3801 1 1 23.2 1.60 3.87 9.42 0.99 5.29 0.05 5882 1 5 26.5 1.88 4.68 10.37 3.54 3.34 1.59 5896 1 4 22.4 1.37 3.53 8.97 1.60 3.65 1.39 6000 1 1 26.8 1.73 4.70 10.39 1.12 6.56 0.07 6029 1 4 27.4 1.71 4.47 10.21 2.26 4.97 0.82 6072 1 3 26.7 1.77 4.30 10.91 2.09 4.46 0.37 6078 1 1 24.9 1.55 4.47 9.55 1.13 6.13 -6079 1 2 25.7 1.54 4.62 10.01 1.08 6.44 0.11 6095 1 6 29.5 1.98 5.32 11.73 4.29 4.17 1.34 6138 1 3 24.4 1.60 4.07 9.75 1.74 4.31 1.38 6162 1 6 30.5 2.16 5.03 11.77 4.22 2.74 3.35 2680 2 2 25.2 1.66 4.07 9.88 1.02 5.89 1.11 2682 2 3 19.8 1.36 3.49 7.98 1.60 3.19 0.89 2760 2 3 31.9 2.27 5.71 12.29 2.43 4.86 2.13 2824 2 6 22.6 1.65 3.74 8.71 3.25 2.84 0.62 2931 2 5 29.1 2.14 5.12 10.05 3.92 4.11 2.03 2986 2 5 29.2 2.15 5.23 10.88 3.77 3.74 1.62 3136 2 5 26.7 1.80 4.82 10.41 3.58 3.41 1.83 3165 2 4 27.1 1.83 4.64 10.74 2.10 3.47 1.93 3319 2 3 25.9 1.77 4.58 10.27 1.83 4.10 1.63 3338 2 4 24.6 1.67 4.28 9.99 1.61 3.03 1.95 3340 2 3 20.8 1.40 3.71 8.33 1.33 3.01 1.51 3344 2 1 24.7 1.66 4.33 8.98 0.97 5.94 1.19 3444 2 1 20.6 1.29 3.84 7.50 0.77 5.00 1.36 3445 2 6 31.9 2.21 5.74 12.36 3.88 3.96 1.40 3448 2 1 29.6 2.13 5.23 13.00 1.14 7.13 -

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3165 3 2 25.5 1.60 3.70 10.04 1.24 5.95 0.69 99Table D-3. Continued DMI Ash CP NDF Sugar Starch NDSF Cow Period Diet ----------------------------------------------------kg/d ---------------------------------------------------3588 2 5 23.7 1.75 4.25 8.92 3.11 3.16 1.25 3621 2 5 29.6 2.05 5.40 11.12 3.82 3.98 1.68 3622 2 6 21.6 1.73 3.61 8.09 3.02 2.59 1.07 3633 2 6 26.2 1.98 3.49 9.82 3.63 3.31 0.94 3661 2 6 24.8 1.74 4.09 9.56 3.33 3.01 1.98 3668 2 1 23.0 1.36 4.15 8.91 1.15 5.25 0.17 3703 2 2 28.1 1.76 4.36 10.34 1.23 6.84 0.56 3708 2 4 22.3 1.53 3.88 9.07 1.62 2.83 1.56 3738 2 5 27.4 1.98 4.63 9.96 3.65 3.36 1.19 3755 2 4 25.5 1.67 4.16 9.91 2.03 3.74 1.31 3801 2 6 23.2 1.69 4.03 9.14 3.05 3.13 0.47 5882 2 2 25.1 1.32 4.29 10.36 1.01 5.91 0.45 5896 2 5 21.6 1.18 3.74 7.96 2.98 3.27 0.49 6000 2 4 22.5 1.50 3.74 9.29 1.54 3.27 1.35 6029 2 3 25.9 1.65 4.44 11.05 1.85 3.79 1.33 6072 2 4 24.8 1.82 4.24 9.37 1.78 3.77 1.51 6078 2 2 18.0 1.29 2.89 7.10 0.74 4.36 0.03 6079 2 3 26.8 1.87 3.91 10.27 2.11 3.74 1.76 6095 2 2 33.4 2.32 4.79 13.02 1.33 7.81 0.85 6138 2 3 25.2 1.76 4.46 9.70 1.87 3.99 1.44 6162 2 1 30.6 1.92 5.24 11.71 1.19 6.91 1.46 2680 3 3 22.6 1.55 3.45 9.49 1.52 3.26 1.01 2682 3 6 20.3 1.38 3.30 8.11 2.61 2.72 0.38 2760 3 2 32.3 2.12 4.90 14.49 1.55 7.46 -2824 3 3 21.0 1.37 3.38 8.83 1.48 2.79 1.10 2931 3 6 28.3 1.83 4.54 10.98 3.53 3.63 1.09 2986 3 4 22.1 1.38 3.56 9.60 1.02 3.18 1.10 3136 3 3 20.6 1.39 3.17 8.84 1.54 2.73 1.02

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6138 3 5 23.7 1.65 3.71 9.29 2.85 3.00 0.63 6162 3 4 24.2 1.60 3.80 10.37 1.55 3.42 0.48 100 Table D-3. Continued DMI Ash CP NDF Sugar Starch NDSF Cow Period Diet ----------------------------------------------------kg/d ---------------------------------------------------3319 3 1 23.1 1.37 3.33 8.99 1.15 5.62 0.46 3338 3 4 16.8 1.01 2.43 6.95 1.30 2.37 0.89 3340 3 3 17.3 1.16 2.58 7.26 1.29 2.25 1.02 3344 3 5 20.4 1.38 3.10 7.76 2.63 2.60 0.65 3444 3 2 26.1 1.47 3.86 10.58 0.92 5.85 0.97 3445 3 2 32.2 1.89 4.87 12.91 1.24 7.41 0.96 3448 3 6 22.1 1.45 3.52 8.41 2.79 3.04 0.51 3532 3 1 24.1 1.59 3.65 8.99 0.85 5.56 0.93 3560 3 2 24.0 1.45 3.61 9.89 0.83 5.60 0.43 3588 3 1 23.9 1.49 3.61 9.43 0.92 5.60 0.55 3621 3 5 26.8 1.95 4.28 10.30 3.59 3.35 0.98 3622 3 4 19.0 1.24 3.04 7.76 1.37 2.37 1.81 3633 3 5 22.8 1.67 3.96 8.71 2.96 2.84 1.07 3661 3 6 23.0 1.63 4.02 9.26 2.92 3.07 0.19 3668 3 3 20.0 1.36 3.52 8.43 1.40 2.48 0.98 3703 3 4 17.6 1.14 2.93 7.32 1.24 2.17 0.88 3708 3 6 16.4 1.24 2.83 6.56 2.24 1.99 0.12 3738 3 2 24.8 1.45 4.15 9.67 0.93 5.98 0.68 3755 3 1 24.6 1.60 4.08 9.65 0.91 5.55 0.30 3801 3 1 21.0 1.36 3.29 8.94 0.75 4.84 -5882 3 1 23.6 1.49 3.22 9.23 0.83 5.63 0.43 5896 3 2 20.1 1.21 3.04 7.13 0.70 4.63 1.23 6000 3 3 19.9 1.33 3.40 8.38 1.21 2.44 1.23 6029 3 4 24.2 1.67 3.78 10.38 1.51 3.31 0.96 6072 3 1 24.9 1.78 3.88 9.17 0.96 5.98 0.54 6079 3 6 25.7 1.75 4.09 10.28 3.13 3.17 0.35 6095 3 6 26.9 1.84 4.44 11.77 3.36 3.46 -

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LIST OF REFERENCES Allen, M. S. 1991. Carbohydrate nutrition in Veterinary Clinics of North America: Food Animal Practice. Vol. 7, No. 2. ALPKEM Corporation. 1987. RFA Methodology. Method number A303-S071. Total Kjeldahl Nitrogen. Calackamas, Oregon. Ariza, P., A. Bach, M. D. Stern, and M. B. Hall. 2001. Effects of carbohydrates from citrus pulp and hominy feed on microbial fermentation in continuous culture. J. Anim. Sci. 79:2713-2718. Asp, N. G. 1993. Nutritional importance and classification of food carbohydrates. In: Plant Polymeric Carbohydrates. Meuser, F., D. J. Manners, and W. Seibel eds. Royal Society of Chemistry, Cambridge, UK. Association of Official Analytical Chemists (AOAC). 1990. Official Methods of Analysis. 15th ed. AOAC, Arlington, VA. Ben-Ghedalia, D., E. Yosef, J. Miron, and Y. Est. 1989. The effects of starchand pectinrich diets on the quantitative aspects of digestion in sheep. Anim. Feed Sci. Tech. 24:289-298. Bergman, E. N. 1990. Energy contributions of volatile fatty acids from the gastrointestinal tract in various species. Physiol. Rev. 70:567-590. Broderick, G. A., N. D. Luchini, W. J. Radloff, G. A. Varga, and V. A. Ishler. 2002a. Effect of replacing dietary starch with sucrose on milk production in lactating dairy cows. U.S. Dairy Forage Research Center 2000-2001 Research Report. pp. 116-118. Broderick, G. A., D. R. Mertens, and R. Simons. 2002b. Efficacy of carbohydrate sources for milk production by cows fed diets based on alfalfa silage. J. Dairy Sci. 85:1767-1776. Broderick, G. A., and W. J. Radloff. 2002. Effects of replacing dietary high moisture corn with dried molasses on production of dairy cows. U.S. Dairy Forage Research Center 2000-2001 Research Report. pp. 106-109. 101

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107 Varga, G. A., W. H. Hoover, L. L. Junkins, and B. J. Shriver. 1988. Effects of urea and isoacids on in vitro fermentation of diets containing formaldehyde-treated or untreated soybean meal. J. Dairy Sci. 71:737. Zinn, R. A. 1991. Comparative feeding value of steam-flaked corn and sorghum in finishing diets supplemented with or without sodium bicarbonate. J. Anim. Sci. 69:905-916. Ziolecki, A., H. Tomerska, and M. Wojciechowicz. 1972. Pectinolytic activity of rumen streptococci. Acta Microbiol. Seria A, 4(21), No. 4:183-188. Zubay, G. L. 1998. Biochemistry, 4th ed. The McGraw-Hill Companies, New York, NY.

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BIOGRAPHICAL SKETCH Colleen Bridget Casey was born in Utica, New York, on February 13, 1979, to Mike and Connie Casey. At the age of 6, she and her family moved to Trenton, Florida, where Colleen completed high school in 1997. Colleen was accepted to the University of Florida, Gainesville, Florida, and received the Florida Academic Scholarship for full tuition. She graduated with honors with a B.S. degree in animal sciences and a minor in food and resource economics on August 11, 2001. At that time she began her graduate program under the supervision of Dr. Mary Beth Hall in dairy cattle nutrition. During graduate school, Colleen was married to Travis Larson on May 11, 2002. They moved to Okeechobee, Florida, in January 2003, where she continued her graduate program. Upon graduation, Colleen plans to work in the Florida dairy industry. 108


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Physical Description: Mixed Material
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THE EFFECTS OF NONFIBER CARBOHYDRATE SOURCE AND
PROTEIN DEGRADABILITY ON LACTATION
PERFORMANCE OF HOLSTEIN COWS
















By

COLLEEN CASEY LARSON


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA


2003

































Copyright 2003

by

Colleen Casey Larson


























This thesis is dedicated to God who provided me the strength and perseverance to
complete my graduate program. It is also dedicated to my family who provided
unconditional support and understanding throughout the attainment of this goal. I would
like to thank my mom, Connie Casey, for the help, encouragement and support she
always demonstrated. I would like to thank my dad, Mike Casey, for always supporting
me in any goal that I wanted to attain. Finally, I want to thank my husband, Travis
Larson, for the support and encouragement throughout this time in our lives.















ACKNOWLEDGMENTS

I wish to express my gratitude to all of the people who contributed and supported

me throughout my Master of Science program. First, I wish to express my appreciation

to the Milk Check Off program that provided funding for this study. Next, I would like

to thank the supervisor of my committee, Dr. Mary Beth Hall, for her patience, guidance,

and diligence in helping me attain this goal. Also, I want to thank the members of my

committee, Dr. Charles Staples, Dr. Adegbola Adesogan, and the late Dr. Bill Kunkle, for

always being willing to take time to answer questions and provide encouragement. Next

I would like to recognize all of the people who helped with the study at the farm or in the

laboratory: Lucia Holtshausen, Heidi Bissell, Celeste Kearney, Jocelyn Croci, Alexandra

Amorocho, Najesda Amorocho, Ashley Hughes, and Connie Casey. I am indebted to

each of them for their diligent efforts. I also own a great deal of thanks to the Dairy

Research Unit (Hague, FL), with special thanks to Carrie Bradley and those who fed the

cows each day. Again, I wish to express my appreciation to all those who made this

research possible.
















TABLE OF CONTENTS

page

A C K N O W L E D G M E N T S ................................................................................................. iv

LIST OF TA BLE S ....................................................... .. ........... ............ .. vii

LIST OF FIGURES .............. ................................. ............. ........... viii

ABBREVIATION S ......... ............................... ........ ............ ix

A B STR A C T ................................................. ..................................... .. x

CHAPTER

1 IN T R O D U C T IO N ............................................................................. .............. ...

2 REVIEW OF THE LITERATURE ON NONFIBER CARBOHYDRATE SOURCE
AND RUMEN UNDEGRADABLE PROTEIN IN RUMINANT DIETS ...............5

N onfiber C arbohydrates................................................................ ....................... 5
P artitio n in g ....................................................... 5
S tarch .................................................................................... . 6
Sugars .......................................................................... 8
Pectic Substances and Pectin..................................... ....................... ........... 14
Effects of Starch, Sugars, and Pectin on Animal Response ......................................18
Effects of RUP and NFC Source in Ruminant Diets ..............................................28

3 EFFECTS OF NONFIBER CARBOHYDRATE SOURCE AND PROTEIN
DEGRADABILITY ON LACTATION PERFORMANCE OF HOLSTEIN
C O W S ........................................................................... 4 2

In tro du ctio n ...................................... ................................................ 4 2
M materials and M methods ....................................................................... ..................43
Cow s, D iets, and Facilities ........................................................................... 43
Sam ple Collection and A nalysis...................................... ........................44
In Situ Rum inal Incubations................................................... ............... ... 47
Rum inal Fluid Sampling and Analysis..................................... ............... 48
Statistical A analysis .......................... .......... ............... .... ....... 49
R results and D discussion ........................... ...... ..... ...... .. .............. 50
Intake and Lactation Performance ............................................ ...............50









Plasma and Ruminal Measures............ .......... ............ ............... 54
C o n c lu sio n s........................................................................................................... 5 7

APPENDIX

A MILK PRODUCTION, COMPOSITION, AND PLASMA MEASURES................65

B RUMINAL PH AND VOLATILE FATTY ACIDS ...............................................71

C IN SITU DEGRADATION OF SORGHUM SILAGE .......... .............. 81

D N U T R IE N T IN T A K E S ................................................................... .....................87

L IST O F R E FE R E N C E S ....................................................................... .................... 10 1

BIOGRAPHICAL SKETCH ............................................................. ............... 108
















LIST OF TABLES


Table pge

2-1 The effects ofNFC source and/or RDP/RUP supplementation on ruminal
characteristics. .........................................................................35

2-2 The effects of NFC source and/or RUP/RDP supplementation on intake, plasma
measures, and milk production and composition. .................................................39

3-1 Ingredient and chemical composition of diets ............. .....................................59

3-2 Nutrient intake by dietary treatm ent .......................... ........... ............. .................. 61

3-3 Milk production, milk composition, blood measures, and efficiency measures by
d dietary treatm en t ................................................................... ............... 6 2

3-4 Ruminal fluid measures by dietary treatment. ................................. ...............63

3-5 Residual NDF by hour of in situ incubation and dietary treatment .......................64

A-i Averages for milk production, fat percent, protein percent, milk urea N (MUN),
and somatic cell count (SCC) by cow, period, and diet ...................................65

A-2 Averages for plasma urea nitrogen (PUN), glucose, and insulin by cow, period,
an d diet. ..................................................................................67

B-1 Volatile fatty acids (VFA) and rumen pH by cow, period, hour of sampling, and
d iet ............... ..........................................................................7 2

C-l In situ degradation of sorghum silage by cow, period, diet, and hour of
sam p lin g .. ................................................................................ 8 1

D-l Offered feed and nutrients by cow, period and diet. ..........................................88

D-2 Refused feed and nutrients by cow, period and diet.. .............................................93

D-3 Intake of feed and nutrients by cow, period and diet.. ............................................97















LIST OF FIGURES


Figure pge

3-1 Temporal patterns of ruminal pH by dietary treatment. Cows were fed following
the 0 sam pling hour. ...................... .................... ............... ........... 60

3-2 Acetate, propionate, butyrate and BCVFA by sampling hour for ST-RUP 0,
ST+RUP *, SF-RUP A, SF+RUP A, and SU-RUP 0, and SU+RUP .. ..........60














ABBREVIATIONS


ADF acid detergent fiber
BCVFA branch chain VFA
BW body weight
CF crude fiber
CP crude protein
CPD citrus pulp diet
CSC cracked, shelled corn diet
DIM days in milk
DM dry matter
DMI dry matter intake
ESBM expeller soybean meal
FCM fat-corrected milk
FPCM fat- and protein-corrected milk
HCP corn and dried citrus pulp diet
HD hominy diet
HMEC high moisture ear corn diet
MUN milk urea nitrogen
NDF neutral detergent fiber
NDFCP neutral detergent fiber crude protein
NDSC neutral detergent-soluble carbohydrate
NDSF neutral detergent-soluble fiber
NEL net energy of lactation
NFC nonfiber carbohydrate
NFE nitrogen-free extract
NSC nonstructural carbohydrate
NRC National Research Council
OA organic acid
OM organic matter
PUN plasma urea nitrogen
RDP rumen degradable protein
RUP rumen undegradable protein
SCC somatic cell count
SF soluble fiber, citrus pulp
SM sugar + malate
SSBM solvent soybean meal
ST starch, ground corn
SU sugar, molasses+sucrose
TMR total mixed ration
VFA volatile fatty acid















Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

THE EFFECTS OF NONFIBER CARBOHYDRATE SOURCE AND PROTEIN
DEGRADABILITY ON LACTATION PERFORMANCE OF HOLSTEIN COWS

By

Colleen Casey Larson

December 2003

Chair: Mary Beth Hall
Major Department: Animal Sciences

The effects of nonfiber carbohydrate source (NFC) and protein degradability on

lactation performance, ruminal, and plasma measures were evaluated using 38

multiparous Holstein cows (82 19 DIM) in a three period partially balanced incomplete

Latin square design with a 3x2 factorial arrangement of treatments. Ruminal pH, organic

acid profile, and NDF disappearance in situ were evaluated with 6 ruminally cannulated

cows within the group. Dietary treatments included three NFC sources (ground corn =

starch = ST; citrus pulp = soluble fiber + sugar = SF; and molasses + sucrose = sugar =

SU) and two concentrations of ruminally undegradable protein (+ or -RUP) achieved by

the addition or omission of expeller soybean meal. Diets were provided ad libitum and

provided similar levels of NFC and NDF regardless of dietary treatment. Data presented

are least squares means. Significant was declared at P<0.05 and tendency at

0.05
23.7 kg/d) and tended to be higher for those fed ST (25.1 kg/d) as compared to the other









NFC sources. Fat- (3.5%) and protein-corrected milk (3.5%FPCM) yield tended to vary

by NFC source with cows consuming SU having higher yields than those on SF (38.4 vs.

36.4 kg/d). Milk fat yield was not affected by dietary treatment. Milk protein yield was

affected by NFC source with cows on ST yielding more protein than those on SU and SF

(1.09 vs. 1.05 and 0.99 kg/d) and cows consuming SU tending to have higher protein

yields compared to SF. Milk urea N and plasma urea N were higher for cows consuming

ST as compared to SU and SF (13.4 vs. 12.6 and 12.5 mg/dl and 15.0 vs. 13.7 and 13.6

mg/dl) and tended to be increased for cows on -RUP as compared to +RUP (13.2 vs. 12.5

mg/dl and 14.6 vs. 13.6). Feed efficiency (3.5%FPCM/dry matter intake) differed for the

interaction of NFC x RUP with +RUP increasing efficiency for SU and SF while

decreasing efficiency for ST. Plasma glucose (67.2 vs. 65.1 mg/dl) and insulin (0.53 vs.

0.47 ng/ml) concentrations were higher for cows fed SU as compared to SF. The molar

percentage of acetate tended to be greater for SF when compared to SU (64.9 vs. 62.9%).

Cows consuming SU had the highest butyrate molar percentage (11.8 vs. 10.4 and

9.38%) and lowest branch chain VFA (1.82 vs. 2.45 and 2.90%) compared to SF and ST.

Additionally, cows consuming SU had the least disappearance of NDF in situ for several

sampling hours. In conclusion, altering the complement of NFC together with RUP has

the potential to alter lactation performance and efficiency measures.














CHAPTER 1
INTRODUCTION

Carbohydrates comprise approximately 65 to 75% of the lactating dairy cow's diet.

The two major classifications of carbohydrates in ruminant diets are neutral detergent

fiber (NDF) and nonfiber carbohydrates (NFC). Among the predominant carbohydrates

are cellulose and hemicelluloses in NDF and starch, pectin, and sugars in NFC (Allen,

1991). In addition to starch, pectin, and sugars (mono- and oligosaccharides), organic

acids (OA), fructans, and any carbohydrates soluble in neutral detergent with heat-stable,

a-amylase, are included in the NFC. These are considered to be highly digestible (98%)

and rapidly fermentable as compared to the carbohydrates in NDF (NRC, 2001).

Currently, there are general but limited recommendations guiding the use of NFC sources

in diet formulations. It is essential that the digestion and yield of metabolizable nutrients

from various NFC types be understood to accurately and efficiently formulate diets for

dairy cattle. Improving the understanding of this large portion of the dairy cattle diet has

the potential to improve animal performance and profitability while maintaining health.

Carbohydrates can provide nutrients for the cow, as well as for the ruminal

microbes. Microbes can use feed carbohydrates for growth, maintenance, and

carbohydrate reserves. Fermentation of carbohydrates yields methane, carbon dioxide,

organic acids, and microbial cells; the latter two products can serve as glucogenic,

lipogenic, and protein substrates to meet the cow's requirements. Starch and maltose that

pass from the rumen can be hydrolyzed in the small intestine by a-amylase and maltase to

monosaccharides. Excepting use by small intestinal microflora, these simple sugars and









those that escaped ruminal fermentation are absorbed by the brush border. Absorption of

monosaccharides provides glucogenic nutrients for maintenance, growth, and production

of the cow. Carbohydrates not digested in the small intestine pass to the cecum and large

intestine where they may be utilized by the microbes to produce the same fermentation

products found in the rumen. The OA produced from hindgut fermentation are absorbed

readily into the blood from the lower digestive tract and may provide up to 9% of the

cow's energy requirement (Bergman, 1990).

Current recommendations suggest that NFC be fed to dairy cattle at 30 to 45% of

the diet on a dry matter (DM) basis (NRC, 2001). However, the NRC (2001) concedes

that the optimal concentration of NFC in dairy cow diets is not well defined. The lack of

clear recommendations may be based at least in part on the wide compositional and

nutritional variation in the components included in the NFC. They vary greatly in

digestion characteristics and yields of metabolizable nutrients. Until recently, practical

methods were not available to measure the different carbohydrates in NFC. A recently

proposed system for partitioning NFC (Hall et al., 1999) offers researchers the ability to

quantitatively evaluate concentrations of starch, sugar, and neutral detergent-soluble fiber

in feeds. The ability to measure these major carbohydrate fractions will allow researchers

to quantitatively evaluate the animal response to them and explore the potential use for

them in diet formulations. Understanding the nutritional value of each NFC type may aid

in the use of all available feeds, including byproducts, to efficiently formulate dairy cow

diets to enhance production and health. With knowledge of the amount of the

carbohydrate fractions represented in feeds, diets may be developed that optimize the

utilization of carbohydrates together with other feed fractions to provide the necessary









metabolizable nutrients for the cow's maintenance and production requirements and

reduce nutrient excretion.

Two general divisions of protein in feeds are ruminally degradable protein (RDP),

which is available for degradation in the rumen by microbes, and ruminally undegradable

protein (RUP), which escapes digestion in the rumen, but may have the potential to be

digested in the small intestine. Two sources of protein are available for digestion in the

small intestine. In addition to RUP, microbial protein also passes from the rumen and

adds to the supply of protein available for digestion in the small intestine. Several factors

affect the amount of feed protein that passes through the rumen undigested including: the

proportional concentrations of non-protein N and true protein, the physical and chemical

characteristics of the protein sources that determine their rate of digestion, and the rate of

passage of feedstuffs from the rumen (NRC, 2001). The amount of microbial protein

arriving at the small intestine may be influenced by RDP, and potentially, by NFC type.

Different types of NFC have been shown to differ in the yield of microbial crude protein

from their fermentation in vitro (Hall and Herejk, 2001). Supplying more microbial

crude protein to the small intestine may decrease the need to supplement a diet with

additional RUP sources. If NFC types differ in microbial yield, they may need to be

complemented with different amounts of RUP to optimize nutrient supply to the cow. If

these optimal concentrations can be achieved there is potential for maximizing the

production of the cow while reducing excretion of N in urine and feces.

The objective of this study was to evaluate the effects of three NFC sources with

two concentrations of RDP/RUP on lactation performance and blood and ruminal

measures. This research is intended to provide a better understanding of how various






4


NFC and protein types can be used in diet formulation to meet the requirements of

lactating dairy cows.














CHAPTER 2
REVIEW OF THE LITERATURE ON NONFIBER CARBOHYDRATE SOURCE
AND RUMINALLY UNDEGRADABLE PROTEIN IN RUMINANT DIETS

Nonfiber Carbohydrates

Partitioning

The first system that partitioned carbohydrates was the proximate analysis or

Weende system developed by Henneberg at the Weende experiment station in Germany

(Maynard and Loosli, 1975). The proximate analysis system divides carbohydrates into

crude fiber (CF) and nitrogen-free extract (NFE) fractions. The CF fraction includes

cellulose, alkali-insoluble hemicellulose and lignin. The NFE fraction includes sugars,

starches, pectin, organic acids (OA), fructans, and the alkali-soluble hemicellulose and

lignin. Proximate analysis was intended to make a clear distinction between the more

digestible (i.e., NFE) and less digestible (i.e., CF) carbohydrates. However, in the rumen,

portions of the CF are sometimes digested and portions of the NFE are indigestible.

These failings of the proximate analysis system in partitioning carbohydrates led to the

development of analyses that are more nutritionally relevant.

The detergent system, originally developed at the USDA (Goering and Van Soest,

1970), divides plant carbohydrates by their solubility in detergent solutions. The feed

components that are insoluble in a neutral detergent solution (pH 7.0) are labeled

neutral detergent fiber (NDF) and include cellulose, hemicellulose, and lignin. The feed

components that are insoluble in an acid detergent solution (pH 2.0) are labeled acid

detergent fiber (ADF) and include cellulose and lignin. These two measures of fiber









differ by their inclusion or exclusion of hemicelluloses. The feed components that are

soluble in a neutral detergent solution with heat-stable, a-amylase are labeled nonfiber

carbohydrates (NFC). These include mono-, di-, and oligosaccharides (sugars), starches,

OA, fructans, and pectic substances (NRC, 2001) and other carbohydrates of the

appropriate solubility. The detergent system is preferred over the proximate analysis

system for feed analysis because separation of the most and least digestible fractions of

the feeds is achieved. However, carbohydrates in the NFC fraction are not uniform in

their nutritional characteristics. Further work has led to partitioning of the NFC as

related to digestion characteristics.

The neutral detergent-soluble carbohydrate system (NDSC) of analysis divides the

NFC into OA, sugars (mono- and oligosaccharides), starch and neutral detergent-soluble

fiber (NDSF). Recently proposed methods (Hall et al., 1999) allow quantitative

measurement of the amounts of sugars and starch and estimation by difference of NDSF

in a feed. These carbohydrates appear to differ in their digestion characteristics and

potential to provide metabolizable nutrients.

Starch

Starch is the predominant storage polysaccharide found in plants. Starch is

composed of glucose (C6H1206) linked by a-(1,4) linkages and a-(1,6) linkages at the

branch points. In its native form, starch is stored by the plant in cold water-insoluble

granules of relatively crystalline structure. The two forms of starch are amylose and

amylopectin. Amylose is a largely linear molecule made up of predominantly a-(1,4)

linked glucose molecules, while amylopectin is considerably more branched, containing

a-(1,6) linkages every 12 to 25 glucose residues (Zubay, 1998). Starch granules vary









from 10 to 30% amylose and 70 to 90% amylopectin (Zubay, 1998) depending on the

plant specie and cultivar.

Depending upon a variety of factors, including processing method, starch has the

potential to be fermented by ruminal microbes, however maximum starch digestion to

monosaccharides requires several bacterial species working together (Huntington, 1997).

Bacterial species vary in their aptitude for digesting starch at different points in the

granule. Bacteria that can hydrolyze the a-(1,6) linkages can provide substrates for

bacteria that may only have the ability to hydrolyze a-(1,4) linkages. These bacteria

include, but are not limited to, Streptoccocus bovis, Butyrivibriofibrisolvens, Bacteriodes

ruminicola, and Selenomonas ruminatium (Huntington, 1997).

Starch that is not degraded and utilized by ruminal microbes may be digested in the

intestines. The pancreas secretes a-amylase which breaks down amylose and

amylopectin into linear oligosaccharides and limit dextrans. The amount of starch

digested post-ruminally can vary from 5 to 20% of starch from the diet with most of that

being digested in the small intestine (Streeter et al., 1989, 1991; Hill et al., 1991; Zinn,

1991).

Corn, wheat, oats, barley, sorghum, and many by-products such as hominy and

bakery waste are common feedstuffs that have high starch contents. Corn contains an

average of 72% of DM as starch (Huntington, 1997), which has the potential to be highly

digestible and rapidly fermented in the rumen. Total tract digestibility of corn ranges

from 91.2 to 98.9% depending on the processing method and grain type, with ground

corn averaging 93.5% (Huntington, 1997). If a starch source is rapidly fermented and

represents a large portion of the diet, ruminal acidosis can develop, which can cause









digestive upset and a depression in intake and digestibility of other nutrients (Nocek,

1997). Management practices that promote consumption of large meals in a short time

frame and heat stress conditions also may contribute to ruminal acidosis. Huntington

(1997) proposed that almost all of the adversities associated with feeding high-grain diets

are caused by excessively rapid fermentation of starch to OA. These OA include acetate,

propionate, and butyrate, as well as lactate. High starch diets have been associated with

relatively increased propionate and decreased butyrate concentrations (Strobel and

Russell, 1986; Friggens et al., 1998; Heldt et al., 1999)

Sugars

The term "sugars" is used collectively to describe mono-, di-, and oligosaccharides.

These are comprised of one, two, or less than twenty monosaccharide (typically hexose

or pentose) residue molecules, respectively (Zubay, 1998). Functionally, sugars

encompass the carbohydrates soluble in 78 to 80% ethanol (Asp, 1993). These sugar

residues include but are not limited to glucose, fructose, galactose, mannose, ribose, and

xylose. Glucose and fructose are the most common monosaccharides found in plants.

Sucrose, the most common disaccharide found in plants, is composed of glucose a-(1,2)

B-fructose (Zubay, 1998). Sucrose, fructose, and glucose are found in relatively high

amounts in molasses, a common cattle feed. Samples from U. S. Sugar Corporation in

Clewiston, Florida from 1997 to 2003 averaged 48.3% total sugar as invert (as-fed) with

23.7% moisture (personal comm., Dr. Chet Fields, 2003). Another feed that can have a

high content of sugars is citrus pulp, but the content is quite variable. Measured values of

sugars in citrus pulp range from 12% to 40% on a dry matter (DM) basis (Hall, 2002).

As with other fermentable carbohydrates, fermentation of sugars can alter the

ruminal environment as well as the supply of metabolizable nutrients to the cow.









Bacteria and protozoa are known to convert a portion of sugars to glycogen (a-linked

storage polysaccharide in bacteria) (Thomas, 1960). The fermentation of sugars in vitro

or in vivo shows variation among sugar sources in the yield of products and effects on the

ruminal environment, and differences with other NFC sources. The digestion of

oligosaccharides, a relatively small part of the sugars in plant material, has not been

extensively studied or described; consequently this thesis will focus on the predominant

mono- and disaccharides in feeds (glucose, fructose, and sucrose). These very small

molecules are typically very readily solubilized and digested.

Using trichloroacetic acid-precipitated crude protein (CP) as an estimate of

microbial CP, Hall and Herejk (2001) showed that sucrose differed from corn starch and

citrus pectin in the temporal pattern of microbial CP yield when fermented with isolated

bermudagrass NDF. Peak microbial CP production from the fermentation of sucrose was

reached within 12.6 hours of fermentation and CP yields were maintained similar to the

peak value through 20 hours of fermentation. In contrast, starch and pectin fermentations

peaked later (hours 15.6 and 13.5, respectively) than sucrose, and the yield of microbial

CP began to decline by the next sampling point, post-peak. Sucrose, glucose, and

fructose have been shown to have increased butyrate and slightly decreased propionate

yields relative to starch (Strobel and Russell, 1986; Heldt et al., 1999). Friggens et al.

(1998) found that molasses increased butyrate concentrations followed by soybean meal,

sweet potato, wheat, and field beans. In other studies with greater than 15% of the

dietary DM as sucrose or molasses, molar proportions of butyrate and propionate in the

ruminal fluid increased whereas acetate decreased and ruminal pH was depressed within

1 h after feeding (Khalili and Huhtanen, 1991; Moloney et al., 1994). The depression in









pH has not been observed where sucrose or molasses made up less than 12% of the diet

DM (Huhtanen, 1988; Petit and Veira, 1994; Maiga et al., 1995). As compared to other

carbohydrates, fermentation of sugars has shown greater potential to yield lactate (Cullen

et al., 1986; Strobel and Russell, 1986; Heldt et al., 1999). When fermenting glucose,

Piwonka and Firkins (1996) found that a decreased rate of NDF digestion was caused by

the residual effect of a proteinaceous inhibitor.

An in vitro study that evaluated the effects of sucrose and lactose at three

concentrations reported limited effects of these sugars on ruminal measures. McCormick

et al. (2001) conducted an in vitro fermentation using three concentrations of sucrose and

lactose (0, 2.5, and 5% of substrate DM) in combination with solvent soybean meal

(SSBM) or expeller soybean meal (ESBM). The smallest NH3-N concentration in the

media was from the 5% sucrose supplement (P = 0.06) (Table 2-1). Greater

concentrations of NH3-N were observed from the SSBM as compared to the ESBM (P=

0.01). Concentrations of lactate, acetate, propionate, and total OA were not affected by

the protein or sugar treatments. Butyrate concentration tended to be greater for the media

containing ESBM and no supplemental sugars than that for SSBM and the five percent

sugars (P = 0.07 for protein, P = 0.10 for sugars) (Table 2-1). There was no indication

given that the ruminal microbes used as inoculum had been acclimated to galactose prior

to collection from the donor animal. It is unknown if the results would have differed if

the ruminal microflora had been adapted to lactose.

The complement of dietary OA and sugars may alter volatile fatty acid (VFA) yield

and pH when starch is fed. Martin et al. (2000) used one ruminally cannulated steer fed

36.3 kg/d of wheat silage and 4.5 kg/d of concentrate supplement to collect ruminal fluid









for an in vitro study. The ruminal contents were collected 1.5 h after feeding and added

to a pH 6.5 medium. Two concentrations of sugar plus malate (SM) (a commercial feed

supplement) were fermented alone or with ground corn or soluble starch at 0.0, 2.25, or

3.25 g/L. In the absence of added corn or starch, both concentrations of SM decreased

final pH (P < 0.05) and increased total VFA, acetate, propionate, and butyrate (P < 0.05)

(Table 2-1). For the ground corn fermentation, additions of SM increased concentrations

of acetate, propionate, and total VFA (P < 0.05) while the greatest level of SM (3.25 g/L)

actually decreased the final pH and butyrate concentrations (P < 0.05). Both

concentrations of SM increased concentrations of acetate, propionate, and total VFA

when soluble starch was included in the fermentation. In contrast, concentrations of

butyrate were reduced when soluble starch was added at 3.25 g/L compared to the control

(P < 0.05).

Differences in fermentation characteristics and effects on fiber digestibility

challenge the notion of the equivalence of starch, mono- and disaccharides. An

interaction with dietary supplementation of ruminally degradable protein (RDP) also

appears to alter the impact of the NFC source. Ruminally degradable protein is protein

that is available for use by the ruminal microbes. Heldt et al. (1999) fed twenty ruminally

fistulated Angus x Hereford steers (average BW = 449 kg) in two consecutive

randomized complete block experiments. Cattle had ad libitum access to low-quality tall-

grass prairie hay. The five dietary treatments were no carbohydrate supplement, starch,

glucose, fructose, or sucrose fed at 0.30% ofbodyweight (BW)/d with RDP (sodium

caseinate 91.6% CP) at 0.031% of BW/d (experiment 1) or 0.122% of BW/d (experiment

2). Ruminal pH and apparent total tract digestibilities of organic matter (OM) and NDF









were not affected by supplemental NFC when feeding the low RDP diet (experiment 1).

However, concentrations and type of OA in the ruminal fluid were dependent on the type

of NFC fed. At low levels of RDP supplementation (0.031% of BW), the greatest OA

concentration was reported with sucrose. The smallest concentration was in steers fed the

monosaccharides, fructose and glucose (P = 0.05; di- vs. monosaccharides) with steers

fed starch having numerically intermediate concentrations between those fed the mono-

and disaccharides (P = 0.41 for starch vs. sugars) (Table 2-1). Starch yielded the greatest

concentrations of acetate (P < 0.01) and propionate (P = 0.11), but less butyrate (P <

0.01) as compared to the sugars. Steers fed fructose and glucose had greater molar

proportions of acetate than did sucrose (P = 0.05) (Table 2-1). Isobutyrate and

isovalerate, the branched chain volatile fatty acids (BCVFA), proportions were decreased

in steers fed the sugar diets as compared starch (0.83 and 1.02, respectively, P < 0.01)

and tended to be even smaller yet for the monosaccharides (glucose and fructose

averaged, 0.53 and 0.45 mol/100 mol, P<0.09) as compared to sucrose (0.67 and 0.65

mol/100 mol).

At the greater (0.122% BW/d) concentration of RDP in experiment 2, ruminal pH

was lesser for the starch supplemented cattle as compared to those supplemented with

sugars (P = 0.04) (Table 2-1). Total OA were greater for starch as compared to glucose,

fructose, and sucrose (P = 0.05). Again, ruminal acetate and propionate proportions were

greater in steers fed starch as compared to those fed sugars (P < 0.01 for starch vs.

sugars) (Table 2-1). Butyrate values were again greater with sugar compared to starch

supplementation (P < 0.01). Isobutyrate and isovalerate proportions were greater for

starch (0.82 and 1.13 mol/100 mol) as compared to sugars (glucose, fructose, and sucrose









averaged, 0.67 and 0.94 mol/100 mol, respectively, P = 0.02 and P = 0.07, respectively),

but mono- and disaccharides did not differ in these BCVFA. Apparent digestibilities of

OM and NDF were lesser for starch supplemented diets (66.7 and 61.2%, respectively)

compared to the sugar supplemented diets (glucose 73.1 and 68.1%, fructose 75.2 and

71.3%, and sucrose 67.7 and 62.3%, respectively) (OM P = 0.04 and NDF P = 0.05, for

starch vs. sugars). The diets with monosaccharides also had greater OM and NDF

digestibility than those with sucrose (OM P = 0.02 and NDF P = 0.03). The authors

concluded that feeding limited quantities of supplements that contained RDP and starch

or sugars to cattle consuming low-quality forage will improve total digestible OM intake.

Another study that evaluated the effects of sugar and starch on ruminal measures

was that of Piwonka and coworkers (1994). In that study six cannulated heifers were fed

three diets in a 3 x 3 Latin square design. The diets were high forage, high forage with

dextrose (5.6% of dietary DM), and a medium concentrate and forage diet (60.3% forage

and 39.7% barley, DM basis). Forage was supplied by orchardgrass hay and corn silage.

Barley was increased to achieve the medium concentrate diet (4.40 and 39.7% of DM for

dextrose and medium concentrate, respectively). Reported nonstructural carbohydrate

concentrations were 25.1% for the high forage diet, 27.2% for the high forage with

dextrose diet, and 34.9% for the medium concentrate diet (% of dietary DM). Total VFA

concentrations were not different between the heifers fed dextrose and concentrate diets

(P > 0.05) (Table 2-1). Additionally, ruminal acetate, propionate, and butyrate

concentrations did not differ by carbohydrate treatment (P > 0.05). Ruminal NH3-N

concentration was greater for the cows consuming dextrose as compared to those

consuming the medium concentrate diet (P < 0.05) (Table 2-1). Mean ruminal pH did









not differ by treatment and remained above 6.0 for all of the diets. Rate of NDF

digestion was greater for the cows consuming the dextrose diet compared to the medium

concentrate (0.0586 vs. 0.0442 h-', respectively, P < 0.05). Extents of NDF and OM

apparent total tract digestibility did not differ by treatment. Apparent ruminal OM

digestibility as a percentage of intake was also greater for heifers consuming the dextrose

diet than the medium concentrate (38.1 vs. 25.7%, respectively, P < 0.05). Efficiency of

bacterial growth (measured as grams of bacterial N per kilogram of OM truly digested in

the rumen) was greater for the heifers consuming the medium concentrate diet compared

to those fed dextrose (37.5 vs. 23.8, respectively, P<0.05). This probably occurred

because a constant and greater supply of ruminally available carbohydrates for microbial

growth without pH depression should allow more efficient capture ofNH3-N (Nocek and

Russell, 1988).

Pectic Substances and Pectin

Neutral detergent-soluble fiber includes the non-starch, non-NDF polysaccharides

that have no covalent linkage with lignin, are soluble in neutral detergent, and are

completely available to fermentation (Van Soest, 1994). The NDSF contain

carbohydrates from both plant cell contents (fructans) and plant cell wall pecticc

substances, mixed linkage 3-glucans). Pectic substances are one of the most prevalent

types of soluble fiber in forages and feeds not of grass origin. There is not a clear

distinction between pectic substances and hemicelluloses, because portions of each can

appear in the chemical analysis for the other (Van Soest, 1994). This complicates the

determination of the absolute amount of pectic substances present in a sample. We will

focus on the neutral detergent-soluble fraction of pectic substances.









Pectic substances, a polysaccharide rich in galacturonic acid, is found in the middle

lamella and other cell wall layers in the plant. It is made up of a galacturonic acid chain,

linked a-(l, 4), interrupted and bent by frequent rhamnose units that may have arabinan

or galactan side chains attached (Jarvis, 1984). The carboxyl groups on the galacturonic

acid residues can be combined with calcium ions or as methyl esters. The pectic

polysaccharides can form large aggregates if calcium is available in excess (Jarvis, 1984).

In contrast to pectic substances, pectin largely represents the galacturonic acid backbone

without the neutral sugar side chains. Starch is hydrolyzed by amylase, whereas pectins

are hydrolyzed by pectinesterases and pectinglycosidases (Dehority, 1969).

Some feeds that contain a relatively high concentration of pectin are citrus pulp,

beet pulp, soybean hulls, and forage legumes. Citrus pulp, a by-product of the citrus

juice industry, is a common dairy feed in the Southeast. Citrus pulp is comprised of the

fruit and other plant material (leaves, stems, etc.) that remain after the juice is extracted

from the fruit. Citrus pulp contains 25 to 44% NDSF (Hall, 2002). As compared to

alfalfa, apple, and sugar beet pectin, citrus pectin has the greatest percent of

polygalacturonic acid at 98.4% and the greatest degree of esterification (Kasperowicz,

1994).

The structural carbohydrate, pectin, is degraded by three groups of bacteria

(Kasperowicz, 1994). First, there are bacterial species that degrade pectin and/or use the

degradation products. Second are the bacterial species that degrade pectin but can only

use the simple sugars. Finally, the third group consists of bacteria that cannot degrade

pectin, but utilize the oligogalacturonides and galacturonic acid from the degradation of

pectin. Prevotella ruminicola, Butyrivibriofibrisolvens, and Lachnospira multiparous









make up the first group of bacteria (Stewart and Bryant, 1988). Streptococcus bovis falls

in the second group, while Selenomonas ruminantium and Fusobacterium belong to the

third group (Tomerska, 1971; Ziolecki et al., 1972). Gradel and Dehority (1972) showed

that pure strains of P. ruminicola, L. multiparous, and B. fibrisolvens were able to

ferment up to 80% of citrus pectin.

Pectin has been shown to yield relatively high amounts of acetic acid compared to

other carbohydrate sources (Strobel and Russell, 1986). Citrus pectin yielded the greatest

concentration of acetic acid in vitro when compared to lucerne, apple, and sugar beet

pectin, although the main end product of fermentation of all of the pectins was acetate

(Kasperowicz, 1994). Hatfield and Weimer (1995) showed that fermentation of citrus

pectin gave an increased acetate to propionate ratio as compared to lucerne pectin, and

they reported an increased yield of acetate from citrus pectin and increased propionate

from lucerne pectin. Marounek and Duskova (1999) grew B. fibrisolvens and P.

ruminicola in cultures with D-glucose or pectin and found that strains grown on pectin

produced more acetate and less butyrate and lactate. Schaibley and Wing (1974) noted

an increase in molar proportion of acetate (64.0 to 70.6% from diets with 0 to 82% of

dietary DM as citrus pulp, respectively) and a decrease in propionate proportion (13.1 to

11.5% from diets with 0 to 82% of dietary DM as citrus pulp, respectively) in ruminal

fluid when feeding increasing concentrations of citrus pulp. Using continuous culture

techniques, Mansfield et al. (1994) reported an increase in molar proportions of acetate

and no difference in total VFA and propionate (Table 2-1). Lees et al. (1990) evaluated

ruminal measures by week of lactation and found that in week 9 and 16 the ruminal VFA

proportions of cows fed sugar beet pulp were greater for acetate and butyrate and lesser









for propionate compared to cows fed maize. They also found that cows consuming

maize-based diets had greater plasma insulin concentrations than those consuming the

sugar-beet pulp based diet. Varying dietary carbohydrate source can result in different

fermentation patterns in the rumen, influencing the hormonal status of the animal and

potentially affecting the response in milk production (Lees et al., 1990). In contrast, Van

Vuuren et al. (1993a) did not detect a difference in ruminal fluid pH or VFA

concentrations in either experiment conducted with cows fed corn products or sugar beet

pulp and soybean hulls.

Pectin-rich feeds have differed from other NFC sources in their support of

production of microbial CP. Hall and Herejk (2001) showed that fermentation of pectin

plus NDF resulted in decreased peak microbial CP yield than did starch plus NDF but

followed a similar pattern of growth. When comparing different pectin sources,

Kasperowicz (1994) concluded that the amount of bacterial protein synthesized was more

dependent on the species of bacteria than the type of pectin fermented. Kasperowicz

(1994) also observed that the depletion of polygalacturonic acid, extent of bacterial

protein synthesis and amount of pectin fermented to end products was the greatest from

citrus pectin, likely due to its simple structure and accessibility to bacterial enzymes.

The consumption of diets rich in pectin sometimes had positive effects on ruminal

digestion. Ben-Ghedalia et al. (1989) found that replacing barley with citrus pulp in

sheep diets resulted in a less acidic pH and increased acetate concentration in ruminal

fluid but a decrease in total VFA and proportion of propionate, valerate, isobutyrate, and

isovalerate (Table 2-1). Ben-Ghedalia et al. (1989) concluded that compared to starch,

citrus pulp created more favorable conditions for microbial utilization of other









carbohydrates in the rumen at least in part due to a more neutral pH. Strobel and Russell

(1986) incubated starch, sucrose, pectin, and a mixture of carbohydrates at a pH of 6.0 or

6.7. Fermentation of all NFC sources was decreased at the lesser pH.

Evaluation of starch- or pectin-rich total mixed rations (TMR) in continuous

culture provided information on fermentation products as well as on microbial

efficiencies. Ariza et al. (2001) compared two dietary treatments that contained hominy

feed or dried citrus pulp in continuous culture. The hominy diet contained starch at 24%

of dietary DM and the citrus pulp diet included NDSF at 14.4% of dietary DM.

Concentrations of CP, NDF, and NDSC were similar for both diets. A greater acetate

proportion was achieved on the citrus pulp diet (P = 0.03) whereas the hominy diet

yielded the most propionate (P = 0.02) (Table 2-1) and BCVFA (3.7 vs. 3.0 mol/100mol,

P = 0.03). The acetate to propionate ratio was expectedly greater from the citrus pulp

diet as compared to the hominy diet (4.1 vs. 2.8, respectively, P = 0.01). Digestibilities

of OM, NDF, ADF, starch, NDSF, and NDSC did not differ by dietary treatment.

Greater concentrations of NH3-N were detected from the hominy diet as compared to the

citrus pulp diet (P = 0.01) (Table 2-1). The efficiency of microbial synthesis tended to be

greater for the citrus pulp diet as compared to the hominy diet. Bacterial synthesis

measured as g of N/kg of OM truly digested was 30.6 for citrus and 27.8 for hominy (P =

0.06). Bacterial synthesis measured as g of bacterial N/g of available N was 80.1 for

citrus and 68.3 for hominy (P = 0.09).

Effects of Starch, Sugars, and Pectin on Animal Response

Performance measurements such as dry matter intake (DMI), milk yield, milk

components, and feed efficiency have varied when replacing starch with soluble fiber

(primarily pectin) or sugar sources. The two major pectin-rich feed sources used in









studies were sugar beet pulp and citrus pulp; molasses and sucrose were the most

commonly used sugar supplements. Cattle consuming diets containing pectin-rich feeds

have been shown to increase intake (Valk et al., 1990; Lees et al., 1990; Chester-Jones et

al., 1991), while including sugars in diets occasionally has resulted in increased intake

(Maiga et al., 1995; Broderick et al., 2002a). When compared to performance on diets

containing more starchy feeds, cows consuming pectin-rich feeds had decreased milk

yield (Van Horn et al., 1975; Leiva et al., 2000; Broderick et al., 2002b) and milk protein

percentage (Mansfield et al., 1994; Leiva et al., 2000; Solomon et al., 2000; Broderick et

al., 2002b) while increasing milk fat concentration (Lees et al., 1990; Mansfield et al.,

1994). The increase in milk fat (concentration or yield) by replacing starch with pectin-

rich feeds has not been observed in other studies (Leiva et al., 2000; Solomon et al.,

2000). Supplementation of sugars has decreased milk protein yield (Sannes et al., 2002)

and percentage (Nombekela and Murphy, 1995) and decreased milk fat yield (Sannes et

al., 2002) compared to starch. In contrast, supplementation of sugars has raised milk fat

yield (Broderick and Radloff, 2002; Broderick et al., 2002a) and shown no effect on

protein yield (Maiga et al., 1995; Broderick and Radloff, 2002; Broderick et al., 2002a).

Still other studies reported no difference in DMI or milk production by varying NFC type

(Fegeros et al.,1995; Malestein et al., 1984). It is not known to what extent varying the

concentration, types, and combinations of NFC may alter lactation performance and

blood and ruminal measures.

The influence of sugar and starch feeding on products of ruminal fermentation,

milk composition, and intake was demonstrated by the work of Sannes et al. (2002). The

diets contained 17% CP (DM basis), fed with corn at 20% of dietary DM or a









combination of corn and sucrose (13.5 and 3.2% of dietary DM, respectively). Diets

were based on corn silage and alfalfa. Total VFA, acetate, propionate, and butyrate

concentrations were not affected by dietary treatment (Table 2-1). Branch chain VFA

concentrations were decreased for the sucrose compared to the corn treatment (1.34 vs.

1.87 mM, P = 0.02). Cows consuming sucrose tended (P = 0.08) to have lesser NH3-N

concentrations than those consuming the diet without sucrose added (Table 2-1). Milk fat

and protein yields were greater for the cows consuming the corn as compared to those

consuming the sucrose treatment (P = 0.05) (Table 2-2). Additionally, milk urea N

concentration (MUN) tended (P = 0.06) to be greater for the sucrose treatment compared

to the corn (Table 2-2). The authors concluded that achieving a beneficial response to

sucrose supplementation may require additional dietary RDP to avoid NH3 limitation.

The effects of replacing starch with sugar on intake, milk composition and ruminal

measures were evaluated by Broderick and Radloff (2002). Forty-eight (8 cannulated)

Holstein cows were fed one of four diets based on alfalfa silage. The diets contained the

following levels of sugars and starch, respectively: 2.6 and 31.3% (0% molasses), 4.2 and

28.4% (4.0% molasses), 5.6 and 25.2% (8.0% molasses), or 7.2 and 23.2% (12%

molasses) on a DM basis. Diets were isonitrogenous, and contained similar

concentrations of NDF and NFC. High moisture shelled corn provided starch while dried

molasses was used to vary the amount of sugars. They found that DMI increased linearly

with increasing sugars (P = 0.04) (Table 2-2). However, since milk and milk protein

yields did not follow the increase in DMI, efficiencies of DM and nitrogen utilization

(milk/DM intake of 1.51 to 1.43 and milk N/N intake of 0.255 to 0.231, P = 0.03 and P=

0.02, respectively) decreased linearly. There was a significant quadratic response for









3.5% fat-corrected milk (FCM) and fat yield (Table 2-2) with the maximum at 3.5%

dried molasses in the diet (P = 0.04 for FCM and P = 0.03 for fat yield). Ruminal

ammonia showed a quadratic effect reaching the smallest concentration when 6.1% dried

molasses was added (P = 0.05) (Table 2-1). The addition of sugars also resulted in a

linear decrease in BCVFA (P = 0.05). Molar proportions of butyrate tended to increase

linearly with the added molasses (P = 0.10).

The effects of replacing starch with sugars using purified substrates were assessed

by Broderick and coworkers (2002a). Forty-eight Holstein cows were fed diets based on

alfalfa silage and contained the following amounts of starch and sugar, respectively: 28.2

and 2.7%, 27.4 and 5.1%, 24.5 and 7.1% or 21.5 and 10.0%. These concentrations were

achieved by feeding decreasing dietary proportions of cornstarch and increasing dietary

proportions of sucrose. Diets were isonitrogenous and contained similar concentrations

ofNDF and NFC. While DMI increased linearly with the addition of sucrose (P = 0.01)

(Table 2-2), there were not subsequent increases in milk production. However, milk fat

yield (P = 0.05) and percentage (P = 0.01) increased linearly with sucrose addition, with

milk fat percentage increasing from 3.8 to 4.2% from no sucrose to 7.5% sucrose,

respectively. In this study, ruminal concentrations of propionate increased (P = 0.04)

(Table 2-1) and BCVFA decreased (P = 0.02) with the addition of sucrose to the diets.

In contrast to other studies that fed sugars, no change in ruminal butyrate concentrations

were detected in this study.

The prepartum feeding of sucrose had small effects prepartum but no detectable

carryover effects in lactation. In the study of Ordway et al. (2002), thirty-four

multiparous lactating Holstein cows were fed diets of 0 or 2.7% sucrose (DM basis) with









sucrose partially replacing ground corn (11.5% of dietary DM as ground corn). Cows

began consuming diets at 30 d prior to expected calving date and were switched to a

lactating cow diet upon calving. Both diets contained corn silage, cottonseed hulls, corn

cobs, soyhulls, alfalfa dehydrate, soybean meal, liquid molasses, protein mix and a

mineral mix. Diets were isonitrogenous with similar concentrations of NFC and NDF.

The control diet contained 21.8 and 6.6% of DM as starch and sugars compared to the

sucrose diet with 20.4 and 8.8% of DM starch and sugars, respectively. Dry matter

intake, body weight, and body condition score were not affected by sucrose treatment.

Plasma glucose tended (P = 0.08) to be greater prepartum for the cows provided the

sucrose diet as compared to the control (Table 2-2). Feeding sucrose did not affect DMI,

insulin, and blood urea N pre- or postpartum or milk production and milk composition

postpartum. While sucrose supplementation increased blood glucose concentrations

prepartum, suggesting absorption of additional glucogenic precursors, a response in

lactation performance was not detected. Although not statistically significant, cows

supplemented with sucrose appeared to have less periparturient health problems.

Numerically, the sucrose-supplemented cows had less incidence of ketosis (4 of 16 in the

control group and 1 of 18 in the sucrose group).

Maiga et al. (1995) demonstrated that feeding of sugar sources with fat altered

lactation response. Forty Holstein cows (28 primiparous and 12 multiparous) were fed

one of the following diets; control, fat (tallow at 2% of dietary DM), molasses plus fat

(8.3% of diet as liquid feed containing molasses plus 19% fat of DM), or dried whey plus

fat (whey at 5.4% and tallow at 2.0% of dietary DM). All diets contained corn silage,

alfalfa hay, shelled corn, and soybean meal. Diets contained similar concentrations of









CP, NDF and total nonstructural carbohydrates. Milk fat and protein percentage tended

to be greater for the cows fed the tallow diet without sugar as compared to those fed the

molasses plus fat and the dried whey plus fat diets (fat: 3.65 vs. 3.53 and 3.40%,

respectively, P = 0.10; protein: 2.98 vs. 2.91 and 2.86%, respectively, P = 0.07). Feed

efficiency was greatest for the tallow (1.49, P = 0.04 for tallow vs. molasses and dried

whey plus fat) followed by the dried whey plus fat (1.46) and then the molasses plus fat

(1.39) (P = 0.05 for molasses plus fat vs. dried whey plus fat). There were no differences

in yields of milk, 3.5% FCM, or DMI between the fat-supplemented diets. Mean ruminal

pH tended to be decreased for the molasses plus fat compared to the dried whey plus fat

(P = 0.06) (Table 2-1). Although not statistically significant (P = 0.11), total VFA

concentration was greater for the molasses plus fat compared to the dried whey plus fat

(Table 2-1). Butyrate concentration was greater for cows fed the molasses and dried

whey plus fat diets as compared to the tallow diet (13.2 and 12.9 vs. 12.5 mol/100 mol,

respectively, P = 0.03).

Low inclusion of sucrose substituted for corn meal modified milk composition in a

study by Nombekela and Murphy (1995). Twenty-four Holstein cows were fed a control

diet or a diet with sucrose at 1.5% of dietary DM. The sucrose replaced 1.5% of DM of

ground corn. Dry matter intake (measured as kg/d, % of BW, and g/kg of BW0.75), milk

yield, and 3.5% FCM were not affected by dietary treatment of sucrose supplementation.

Milk protein concentration was greater for the cows consuming the control diet as

compared to the sucrose supplemented diet (3.51 vs. 3.28%, P<0.01). Milk fat yield

tended to be greater for the sucrose supplemented cows as compared to those consuming









the control diet (P = 0.07) (Table 2-2). Feed efficiency (3.5% FCM:DMI, kg/kg) was not

affected by dietary treatment.

Variability in the effects of feeding starch- or pectin-rich diets on lactation

performance was illustrated in studies by Leiva et al. (2000). In this study cows were fed

one of two diets with the NFC fraction providing predominately either citrus pulp (CPD)

or hominy (HD). Eleven multiparous Holstein cows including three ruminally

cannulated were evaluated in a two period reversal design. All diets contained corn

silage, alfalfa hay, cottonseed hulls, distillers grains, soybean meal, whole cottonseed and

a mineral mix in addition to the NFC sources. The average concentrations of CP and

NDF for the diets were 17.9 and 36.1% (DM basis), respectively. Starch made up 15.1%

(CPD) and 26.5% (HD) of the diets on a DM basis. Sugars were 4.8% of DM in the CPD

and 2.5% of DM in the HD diets. Intakes in kg/d of DM, CP, and NDF were all similar

with cows on the CPD diet consuming more sugars and NDSF and cows on the HD

consuming more starch (P<0.01). Yields of milk, 3.5% fat- and protein-corrected milk

(FPCM), fat, and protein, and fat percentage were not affected by dietary treatment.

Only milk protein percentage differed by diet, with cows on the HD diet having an

increased protein concentrations than those on CPD (P = 0.01) (Table 2-2). Feed

efficiency (3.5% FPCM/DMI, kg/kg) also was not different by treatment (1.45 vs. 1.47

for CPD and HD respectively, P = 0.65). Ruminal pH, and concentrations of total VFA,

acetate, propionate, butyrate, and lactate did not differ by dietary treatment.

When replacing maize with sugar beet pulp, milk fat and fat-corrected milk yields

have increased. Lees et al. (1990) fed twelve Friesian cows and sixteen heifers a high

fiber or high starch concentrate supplement fed with low (1.8% urea as-fed) or high









protein (24.0% soybean meal and 6.0% fishmeal as-fed). All diets contained hay and

barley. The high fiber, low and high protein supplements contained 35.0 and 24.5%

sugar beet pulp, 35.2 and 24.5% barley, and 18.0 and 12.5% ground maize (as-fed),

respectively. The high starch, low and high protein supplement contained 40.2 and

28.0% flaked maize, 31.8 and 22.2% barley, and 16.2 and 11.3% ground maize (as-fed),

respectively. Cows fed the sugar beet pulp had greater DMI than cows fed the maize diet

(P < 0.05) (Table 2-2). Milk fat percentage (3.9 vs. 2.8%) and FCM (20.3 vs. 17.9 kg/d)

were also increased (P < 0.05) with feeding sugar beet pulp, while milk yield was not

(Table 2-2).

In an early study, Van Horn et al. (1975) fed 36 cows (Holsteins, Jerseys, and

Guernseys) diets containing 5% molasses, 25% sugar cane bagasse and urea or soybean

meal. Changing NFC source was accomplished by replacing ground corn with either 8 or

43.1% of dietary DM with dried citrus pulp. Cows fed the high corn diet produced more

milk (Table 2-2) and had a decreased milk fat percentage (3.41 vs. 4.41%) than those

consuming the high citrus diet. Dry matter intake and milk protein percentages were not

affected by dietary treatment.

Even within the same experiment station, animal intake response to

supplementation with starch- or pectin-rich feeds has not always differed, although

changes in digestibilities have been observed. Van Vuuren et al. (1993a) conducted two

separate experiments comparing the effects of corn products vs. sugar beet pulp. In

experiment 1, the three diets fed to Dutch Friesian multiparous cows were ryegrass alone,

ryegrass supplemented with corn meal and hominy (47.5 and 50% of supplement,

respectively, DM basis) and ryegrass supplemented with sugar beet pulp and soybean









hulls (82.5 and 15.0% of supplement, respectively, DM basis). For both carbohydrate

sources supplemented, intake of OM increased by 0.2 to 0.3 kg/d. In experiment 2, corn

silage replaced perennial ryegrass. Increasing the proportion of corn meal (0, 44, or

87.5% DM basis) or sugar beet pulp (0, 44, or 78.5% DM basis) in the supplement did

not affect OM intake. Although intake remained unchanged, Van Vuuren et al. (1993b)

reported a digestibility response when feeding three Dutch Friesian multiparous lactating

cows fitted with ruminal and duodenal cannulas one of three experimental diets. The

diets were the following: grass (14.5 kg/d of DM), grass with a starch supplement (9.3

and 5.3 kg/d of DM, respectively), and grass with a fiber supplement (9.4 and 5.4 kg/d of

DM, respectively). The starch supplement contained 47.5% corn meal and 50.0%

hominy, whereas the fiber supplement contained 82.5% sugar beet pulp and 15.0%

soybean hulls (% of concentrate, DM basis). Dry matter intake and ruminal OM

digestibility were not affected regardless of supplement type. Ruminal digestibility of

NDF increased from 74.5 to 79.2% when starch was replaced with the fiber supplement.

A study with beef cattle demonstrated a positive intake response to feeding pectin-

rich feeds. Chester-Jones et al. (1991) fed beef steers one of six diets containing three

different concentrations of sugar beet pulp and two soybean products as the protein

sources. Diets contained either 10% soybean meal or 9.4% alcohol-treated, defatted

soybean flakes (DM basis) with 0, 15, or 30% sugar beet pulp (DM basis). All diets were

fed with corn, alfalfa pellets, urea, and a mineral mix. The DMI was greatest for steers

fed the 15% beet pulp diet when soybean meal was the main protein source. When beet

pulp was increased to 15%, DMI increased 0.43 kg/d. Intake increased linearly with

increasing dietary concentration of sugar beet pulp when soybean flakes were the main









protein source. Regardless of protein source, feed efficiency (kg of DMI/kg of gain)

decreased linearly with increasing sugar beet pulp in the diet. Average daily gains were

not affected by beet pulp treatment.

In two conflicting studies, Valk et al. (1990) reported intake increases from starchy

feeds and then from pectin-rich feeds. In trial 1, Valk et al. (1990) fed multiparous

lactating cows fresh ryegrass (17.5% CP and 14.6% sugar) with a fibrous (beet pulp) or

starchy (maize) supplement. Cows fed maize consumed 0.6 kg/d more DM and produced

2.6 kg/d more milk than cows fed beet pulp. In trial 2, an equal mix of maize and beet

pulp constituted a third type of supplement (fibrous/starchy) and again the forage source

was ryegrass (21.4% CP and 11.3% sugar). Dry matter intake was greatest for cows fed

the most beet pulp. Digestibility of NDF was greater for the cows fed beet pulp as

compared to those fed maize meal (70.8 vs. 66.1%). Yields of milk, fat, and protein were

not different by type of supplementation (Table 2-2). Differences in the quality of

ryegrass may have contributed to the conflicting results in trials 1 and 2, although the in

vitro OM digestibility of both cuttings was 81%.

A study with sheep found no change in lactation performance with feeding citrus

pulp. Fegeros et al. (1995) conducted a study with 26 lactating ewes. They received 700

g of alfalfa hay, 300 g of wheat straw, and 550 or 580 g of concentrate with 0 or 30%

citrus pulp, respectively. Dried citrus pulp replaced portions of grains (maize and

barley), soybean meal, and wheat middlings. No effect of dietary treatment was detected

on DMI, milk yield, FCM yield or milk fat and protein content.

In contrast to other studies with lactating dairy cows, Friggens et al. (1995)

detected no differences between feeding starch-and pectin-rich diets. In that study









eighteen lactating Friesian cows (126 days in milk) were fed diets containing hay (8.9%

CP and 73.4% NDF) and concentrate in a 40:60 ratio (DM basis). The three concentrate

treatments were the following: 1) 0% sugar beet pulp, 56.4% barley grain, and 20%

ground corn, 2) 37.3% sugar beet pulp, 28.2% barley grain, and 10% ground corn, and 3)

74.5% sugar beet pulp, 0% barley grain, and 0% ground corn. Dry matter intake was not

reported in this study. Feeding increasing amounts of sugar beet pulp had no effect on

milk yield, milk composition, body condition, or body weight.

Changing the dietary source of NFC fed to lactating dairy cows has been shown to

alter the ruminal environment. Though not always consistent, effects have been observed

on proportions of VFA, concentration of rumen NH3-N, and extent of fiber digestion with

feeding starch, sugars or pectin-rich feeds. These changes in ruminal characteristics

likely altered the flow of potentially metabolizable nutrients to the cow throughout the

digestive tract. Altering the nutrients provided to the cow may have the potential to

change milk production and composition.

Effects of RUP and NFC Source in Ruminant Diets

Ruminally undegradable protein (RUP), also called undegradable intake protein

and bypass protein, is feed protein that escapes microbial degradation in the rumen; it

may or may not be digested and absorbed in the small intestine. Digestion of RUP and

microbial CP in the small intestine provides metabolizable amino acids to the cow. Other

than urea, most feeds that contain N have some RUP; some feeds having relatively

greater concentrations than others. The latter include heated and/or treated soybean

products, fish meal, meat and bone meal, blood meal, feather meal, and brewers and

distillers grains. There is great variation in the digestibility of these products in the small

intestine, as well as in the results in feeding studies. Santos et al. (1998) reviewed 88









lactation studies from 1985 to 1997 and found inconsistent animal production responses

to RUP supplementation. Only 17% of the studies reported greater milk yield by cows

fed diets of greater RUP concentration. Of these, cows fed fish meal or treated soybean

meal showed the most positive milk yield response.

Although it is clear that varying the intake of readily fermentable carbohydrates

affects the supply of protein to the small intestine, little research has been done that has

addressed the relationship of dietary concentration of RUP with that of different NFC

sources. Microbial CP yield is influenced by carbohydrate source, nitrogen source, rate

of carbohydrate fermentation, bacterial growth rate, dilution rate and pH (Van Kessel and

Russell, 1995). Varga et al. (1988) reported a decrease in microbial growth and

depressed fiber and protein digestibilities in vitro with substrates having NSC:RDP ratios

greater than 6.0. Supplying more microbial crude protein to the small intestine may

decrease the need to supplement a diet with additional RUP. If NFC sources differ in

their support of microbial yield, they may need to be complemented with different

amounts of RUP to optimize nutrient supply to the cow.

Companion studies that specifically evaluated the effect of NFC type and RUP

supplementation were carried out by Broderick et al. (2002b). They fed 48 multiparous,

lactating Holstein cows grouped into six blocks based on covariate protein yield (Trial 1)

and six multiparous, lactating Holstein cows fitted with ruminal cannulae randomly

assigned to a 6 x 6 Latin square design. The diets included one of three carbohydrate

sources (high-moisture ear corn, HMEC; cracked shelled corn, CSC; and a 50:50

mixture of high-moisture ear corn plus dried citrus pulp, HCP) fed with or without

ESBM. All diets were fed as TMR containing alfalfa silage at 50% of DM and ryegrass









silage at 10% of DM. All diets contained 26.2 to 29.0% of DM as NDF and 38.2 to

43.7% of DM as total NFC. Expeller soybean meal replaced urea to supply the ruminally

undegradable protein. The CP was at least 3% greater for each of the ESBM

supplemented diets (18.6 to 19.0% of DM) as compared to the diets without ESBM (22.1

to 22.7% of DM). The HCP diets contained 4.9 and 5.3% sugars and the corn diets

ranged from 2.7 to 3.5% sugars (DM basis). Starch ranged from 23.4 to 31.0% of DM

for the corn diets compared to 20.0 and 17.1% of DM for the HCP diets. The described

orthogonal contrasts compared ESBM vs. no supplement, HMEC vs. CSC, HMEC vs.

HCP, CSC vs. HCP, and ESBM on HMEC and CSC vs. ESBM on HCP. In trial 1, DMI,

yields of milk, 3.5% FCM, fat and protein and concentrations of MUN and plasma urea N

(PUN) were all greater for the diets containing ESBM. Cows fed HMEC and CSC

consumed more DM than cows fed HCP (P = 0.08 and P = 0.02, respectively) (Table 2-

2). Milk and 3.5% FCM yields were both greater for the cows fed the two corn diets as

compared to the diet containing citrus pulp (P = 0.01 for milk yield, HMEC vs. HCP and

P = 0.02 for milk yield, CSC vs. HCP) (Table 2-2). Milk components followed suit, with

cows consuming the HMEC and CSC having greater yields of milk fat (P = 0.01 for fat,

HMEC vs. HCP, P = 0.08, CSC vs. HCP) and protein (P < 0.01 for protein, HMEC and

CSC vs. HCP) as compared to those fed HCP. Carbohydrate source did not affect MUN

and PUN concentrations. Plasma glucose was only greater for the cows consuming CSC

compared to HCP (P = 0.01) (Table 2-2).

In the second study cows were in late lactation and ruminal effects of diets were the

focus. Ruminal pH and NH3-N concentration were greater for the cows fed the +ESBM

diets (P = 0.03 and P<0.01, respectively) (Table 2-1). Molar proportions of acetate and









butyrate were decreased for cows not supplemented with +ESBM (P = 0.07 and P =

0.01, respectively). Ruminal fluid pH was less acidic in cows consuming the CSC diets

compared to those fed the HMEC or HCP diets (P = 0.04 and P = 0.03, respectively);

however, there was little variation with average pH ranging from 6.10 to 6.24. Ruminal

NH3-N was also greatest for cows fed CSC as compared to those fed HMEC and HCP (P

< 0.01 and P = 0.04, respectively). Differences (P < 0.10) in the molar proportions of

acetate were not detected in this study for the contrasts for carbohydrate source. Molar

proportions of propionate were greatest for HMEC followed by CSC and then HCP (P =

0.03 for HMEC vs. CSC, P<0.01 for HMEC vs. HCP, and P = 0.04 for CSC vs. HCP).

Molar proportions of butyrate were smallest from cows fed HMEC intermediate for cows

fed CSC and greatest for cows fed HCP (P = 0.03 for HMEC vs. CSC, P<0.01 for

HMEC vs. HCP, and P<0.01 for CSC vs. HCP). Acetate to propionate ratio was greatest

for the HCP diets (3.42 and 3.45, for -ESBM and +ESBM, respectively) followed by

CSC (3.25 and 3.30, for -ESBM and +ESBM, respectively) and HMEC (3.03 and 3.17,

for -ESBM and +ESBM, respectively) (P = 0.08 for HMEC vs. CSC, P<0.01 for HMEC

vs. HCP, and P 0.10 for CSC vs. HCP) which expectedly followed the inverse of the

propionate values.

Based on their results, Broderick et al. (2002b) concluded that the NH3 and VFA

patterns suggested that the carbohydrate fermentation decreased in the order of HMEC >

CSC > HCP, proposing that site of digestion may have played a role. In this study, the

diet with dried citrus pulp was unable to support the production achieved by the two corn

(starch) diets. While effects of ESBM were detected in this study, concentration of total









CP differed in the no supplement vs. the ESBM supplemented diets and this may have

affected production.

In a study similar to that of Broderick et al. (2002b), Solomon et al. (2000) fed

twenty lactating Holstein cows diets of high starch or high pectin with (average of 6.0%

of DM as ether extract) or without (average of 3.3% of DM as ether extract) the addition

of full fat extruded soybeans. The high starch was achieved by feeding elevated amounts

of corn grain and the high pectin by increasing the amount of dry citrus pulp pellets fed.

Diets contained similar concentrations of CP, NDF, and total NSC. Dry matter intake

was greater for the cows fed high starch (P < 0.01) and the extruded soybeans (P < 0.05)

(Table 2-2). Milk yield was greater for the extruded soybean diets compared to those

without the beans (P < 0.01). Milk protein concentration was greater for cows

consuming more starch (P < 0.01) without the extruded soybeans (P < 0.01). Milk fat

yield was greater for cows consuming the extruded soybean diets (P < 0.01) (Table 2-2).

Elevated MUN concentrations were detected with the addition of extruded soybeans to

the diets (P < 0.01) (Table 2-2).

With animal by-products as the RUP source, Mansfield et al. (1994) compared the

animal response to supplementation with starch from corn or pectin and sugars from

sugar beet pulp. Forty-six Holstein cows were assigned one of four dietary treatments

comparing corn and dried sugar beet pulp with either soybean meal (more RDP) or

animal by-products (more RUP from meat and bone meal, feather meal, and blood meal)

in a randomized complete block design, with a 2 x 2 factorial arrangement of treatments.

All diets contained alfalfa pellets, alfalfa hay, corn silage, and concentrate. Beet pulp

replaced about half of the corn (15% of DM) to achieve the two carbohydrate treatments.









Significance was declared at P < 0.05. Dry matter intake (kg/d and % of BW) was

greater for cows fed corn than for those consuming the beet pulp diet (3.97 vs. 3.69% of

BW) (Table 2-2). Milk yield and 3.5% FCM were not affected by dietary treatment.

Milk fat concentration was greater for the cows fed the beet pulp (3.82 vs. 3.64%) but

this did not translate into an increased milk fat yield (Table 2-2). Milk protein percentage

(3.01 vs. 2.90%) and yield (Table 2-2) were decreased for the cows fed the beet pulp diet

compared to the corn diet. Feed efficiency (3.5% FCM/DMI, kg/kg) was greater for the

cows consuming beet pulp as compared to those consuming corn (1.67 vs. 1.55). Milk

protein concentration was greater for the cows fed the soybean meal diet as compared to

the RUP animal by-product diet (3.00 vs. 2.91%, respectively). Dry matter intake and

feed efficiency were not affected by protein type.

Feeding a commercial sugar product and two protein sources, McCormick et al.

(2001) evaluated milk production and composition response. Thirty-two multiparous

Holstein cows were fed the following diets; solvent SBM (SSBM), SSBM plus 5%

brown sugar food product, ESBM, or ESBM plus 5% brown sugar food product. All

diets contained ryegrass, ground corn and a mineral mix. Intake of DM was not affected

by protein source, sugar, or the interaction of the two. While not statistically significant

(P = 0.15 for the protein x sugar interaction), milk yield numerically increased with the

addition of sugars to the SSBM diet and decreased with the addition of sugars to the

ESBM diet (Table 2-2). Milk fat percentage was numerically greater for the ESBM diets

compared to the SSBM (3.39 and 3.53 vs. 3.24 and 3.25%, respectively, P = 0.13).

Yields of 3.5% fat-corrected milk, fat and protein were not affected by dietary treatment.









Plasma urea N concentration was greater for cows fed the sugar supplemented diets (P =

0.01) (Table 2-2).

Although the information is limited, it appears that NFC source together with RUP

supplementation have the potential to change ruminal fermentation characteristics,

nutrient supply and consequently production response. More studies that feed various

NFC types and different ruminal degradabilities of protein are needed to gain a

comprehensive understanding of their effects on VFA, ruminal pH, NH3-N, blood

metabolites, milk production and milk composition.










Table 2-1. The effects of NFC source and/or RDP/RUP supplementation on ruminal
characteristics. Studies are listed in alphabetical order.
Reference VFA, Acetate, Propionate, Butyrate, Ruminal NH3-N,


and Treatment


mM


Ariza et al. (2001), continuous culture
Citrus pulp 104
Hominy feed 101
Broderick et al. (2002a), 8 cannulated cows
0.0% sucrose and 7.5%
corn starch 106
2.5% sucrose and 5.0%
corn starch 107
5.0% sucrose and 2.5%
corn starch 112
7.5% sucrose and 0.0%
corn starch 104
Broderick et al. (2002b), 6 cannulated cows
High-moisture ear corn 103
(1)
Cracked shelled corn (2) 102
High-moisture ear corn +
dried citrus pulp (3) 107
1 + expeller soybean meal 101
2 + expeller soybean meal 107
3 + expeller soybean meal 108
Broderick and Radloff (2002), 8 cannulated
0% dried molasses and
29% high moisture corn 129
4% dried molasses and
25% high moisture corn 129
8% dried molasses and
21% high moisture corn 136
12% dried molasses and
17% high moisture corn 132
Chester-Jones et al. (1991), in vitro
Soybean meal (SBM) +
0% beet pulp 134
SBM +
15% beet pulp 130
SBM +
30% beet pulp 123
Alcohol treated, defatted
soybean flakes (ATSBF)
+ 0% beet pulp 137
ATSBF +
15% beet pulp 127
ATSBF +
30% beet pulp 122


------------mol/100 mol-------------


68.9
62.6


60.9

60.8

60.1

60.4

62.7

63.4

63.7
63.8
63.9
64.3
cows

62.2

63.6

62.0

64.1


41.3

45.0

47.2


42.4

45.9


16.7
22.7


20.2

21.1

21.4

22.0

20.8


18.7
20.3
19.4
18.7


22.0

20.8

21.9

19.8


40.8

42.3

40.8


40.3

42.4


11.4
11.0


pH mg/dl

--- 9.30
--- 14.2


14.3 6.19 6.93

13.1 6.16 6.87

13.5 6.19 6.21

14.0 6.21 5.75

11.4 6.10 12.8

11.7 6.17 18.5


13.0
11.0
11.6
12.3


6.12
6.17
6.24
6.15


15.2
18.5
20.2
18.9


11.5 5.81 11.3

11.3 5.88 9.12

11.9 5.79 10.7

12.0 5.91 10.7


12.6 ---

8.80 ---

7.80 ---


12.6 ---

7.30 ---


47.0 43.9


5.80










Table 2-1. Continued


VFA,
mM


Reference


Heldt et al. (1999), 20 cannulated steers
Low RDP
(0.031% BW/d)
Control ---
Starch ---
Glucose ---
Fructose ---
Sucrose ---
High RDP
(0.122% BW/d)


Acetate, Propionate, Butyrate,
-------------mol/100 mol-------


76.1
70.3
59.3
58.8
56.3


Control --- 73.5
Starch --- 69.5
Glucose --- 61.5
Fructose --- 59.8
Sucrose --- 59.7
Huhtanen (1988), 4 cannulated bulls
Barley 98.1 65.2
Barley + molasses 99.7 62.0
Beet pulp 100.5 67.6
Beet pulp + molasses 93.0 65.5
Khalili and Huhtanen (1991), 4 cannulated bulls
Control (starch) 105 63.6
Sucrose (1 kg/d) 104 58.9
Leiva et al. (2000), 11 cannulated cows
Citrus pulp diet 116 67.7
Hominy diet 106 67.4
Maiga et al. (1995), 10 cannulated cows
Control 99.5 60.1
Fat (2% tallow) 86.6 61.1
Molasses + fat 96.8 60.8
Dried whey + fat 88.9 61.4
Mansfield et al. (1994), Continuous culture
Main Effects
Corn 113 58.7
Beet pulp 110 61.6
Soybean meal 112 60.5
Animal by-product 110 59.8


13.3
17.1
15.5
13.5
15.5


14.0
16.4
14.1
14.2
14.4

15.5
17.1
17.5
18.5


9.0
10.0
18.6
19.7
20.9


10.6
10.3
17.5
18.9
19.5

16.1
17.9
12.8
13.7


Ruminal NH3-N,
pH mg/dl


6.40
6.36
6.28
6.36
6.23


6.56
6.13
6.16
6.29
6.22

6.33
6.21
6.40
6.45


0.13
0.35
0.27
0.49
0.28


0.43
3.39
4.19
3.99
2.63

5.78
10.0
6.19
6.20


17.8 14.9 6.28 17.6
16.5 19.7 6.03 9.90

20.8 11.5 6.19 ---
21.4 11.2 6.24 ---

23.4 12.8 6.71 14.5
22.6 12.5 6.82 12.8
22.9 13.2 6.68 11.7
22.4 12.9 6.85 10.5


21.7
20.5
21.1
21.1


15.3
14.0
14.2
15.1


--- 21.0
--- 17.9
--- 21.8
--- 17.0










Table 2-1. Continued


VFA,
mM


Reference


Moloney et al. (1994), 6 cannulated steers
Barley 71.2 66.5
Molasses 71.7 58.4
Petit and Veira (1994), 6 cannulated steers
Silage alone 100 70.8
7.5% molasses (mol) 103 71.2
silage + 15% mol 101 70.8
7.5% canola meal (cm) 102 71.6
5.5% cm and 7.5% mol 107 71.5
3.6% cm and 15% mol 103 70.7
15% cm 104 70.8
Piwonka et al. (1994), 6 cannulated heifers
Control 82.4 70.0
Dextrose (5.6% of
DM) 91.2 68.9
Medium concentrate
(barley) 90.5 68.7
Ben-Ghedalia et al. (1989), cannulated rams
16.3% dried
citrus pulp 82.4 65.0
67.5% dried
citrus pulp 74.4 69.1
Kasperowicz (1994), in vitro


Sugar beet pectin
P. ruminicola
Sugar beet pectin
L. multiparous
Sugar beet pectin
B. fibrisolvens
Sugar beet pectin
mixed culture
Citrus pectin
P. ruminicola
Citrus pectin
L. multiparous
Citrus pectin
B. fibrisolvens
Citrus pectin
mixed culture


3.64

1.76

0.97

4.10

5.19

2.04

1.82


Acetate, Propionate, Butyrate,
-------------mol/100 mol-------


15.8
16.6

17.0
17.1
17.5
17.0
16.8
17.5
17.5

16.7

18.1

16.7


17.6

14.4


14.0
23.0

8.69
8.88
9.13
8.48
8.94
9.17
8.43

9.6

9.9

11.1


14.3

14.2


-------------- M/00 ml--------------

1.73

1.76

0.74 -


2.74

2.63

2.71

1.47


1.25


0.15


4.26 3.08 1.05


Ruminal
pH

6.94
6.86

6.59
6.52
6.50
6.47
6.50
6.47
6.47


NH3-N,
mg/dl

9.26
5.63

10.23
6.88
5.93
9.59
7.74
7.54
12.16


--- 11.9

--- 11.7

--- 9.8


6.18

6.42


0.12










Table 2-1. Continued
Reference VFA A
and Treatment --------------
Martin et al. (2000), in vitro fermentation
No substrate
Sugar + malate (0.0 g/L) 39.8
Sugar +
malate (2.25 g/L) 66.8
Sugar +
malate (3.25 g/L) 64.1
Ground corn
Sugar + malate (0.0 g/L) 86.8
Sugar +
malate (2.25 g/L) 102
Sugar +
malate (3.25 g/L) 101
Soluble starch


Sugar + malate (0.0 g/L) 89.5
Sugar +
malate (2.25 g/L) 101
Sugar +
malate (3.25 g/L) 103
McCormick et al. (2001), in vitro ferme
Solvent soybean meal 33.4
Expeller soybean meal 29.1
Control 32.8
2.5% lactose 31.3
5.0% lactose 30.3
2.5% sucrose 31.6
5.0% sucrose 30.3
Sannes et al. (2002), 4 cannulated cows
Starch 131
Sucrose 123
Strobel and Russell (1986)
In vitro, pH 6.7
Starch ---
Sucrose ---
Pectin ---
In vitro, pH 6.0
Starch ---
Sucrose ---
Pectin ---


cetate Propionate Bu
---------mM-----------------


31.0

49.3

46.3

53.0

52.2

55.2


53.6

62.5


64.5
nation
20.2
18.6
18.3
20.5
19.0
19.6
19.4

85.3
77.8


5.1
4.7
10.1

2.7
1.7
5.0


4.30


18.9

13.2

17.5

18.1

8.21
7.27
7.89
7.45
7.88
8.63
6.83

26.3
27.1


2.9
2.1
1.3

1.1
1.1
0.7


ityrate Ruminal NH3-N,
--- pH mg/dl


3.1 6.57

5.1 6.40

5.0 6.40


18.8

17.6

15.0

20.4

19.1

18.1

3.33
2.97
3.63
3.22
2.95
2.80
3.17

16.2
15.5


0.8
1.1
0.2

0.7
0.7
0.3


6.00

5.90

5.80

5.92

5.96

5.96

6.67
6.79
6.77
6.78
6.78
6.78
6.78


9.36
8.52
9.13
9.23
9.09
8.76
8.45


--- 6.89
--- 5.45


6.7 ---
6.7 ---
6.7 ---

5.8 ---
5.5 ---
5.8 ---










Table 2-2. Effects of NFC source and/or RUP/RDP supplementation on intake, plasma
measures, and milk production and composition. Studies are listed in


Reference
and Treatmi


alphabetical order.
DMI, 1


ent


Ailk, Fat, Protein,


------------------- kg/d -------------


Broderick et al. (2002a), 48 lactating cows
0.0% sucrose
7.5% corn starch 24.5 38.9 1.47 1
2.5% sucrose
5.0% corn starch 25.6 40.4 1.53 1
5.0% sucrose
2.5% cornstarch 26.0 40.0 1.65 1
7.5% sucrose
0.0% corn starch 26.0 39.4 1.62 1
Broderick et al. (2002b), 48 lactating cows
High-moisture
ear corn (1) 20.0 34.5 1.18 1
Cracked shelled
corn (2) 20.9 33.6 1.11 1
High-moisture
ear corn + dried
citrus pulp (3) 19.2 29.9 0.98 (
1 + ESBM 21.8 35.8 1.30 1
2 + ESBM 21.9 36.5 1.26 1
3 + ESBM 20.2 34.2 1.15 (
Broderick and Radloff (2002), 48 lactating cows


0.0% dried
molasses and
29.0% high
moisture corn
4.0% dried
molasses and
25.0% high
moisture corn
8.0% dried
molasses and
21.0% high
moisture corn
12.0% dried
molasses and
17.0% high
moisture corn


.24

.28

.29

.28


.01

.00


).80
.06
.11
).96


38.0 1.54 1.19


25.8 37.5 1.59 1.14



26.2 38.9 1.63 1.23



26.0 36.7 1.47 1.09


Fegeros et al. (1995), 6 lactating ewes
Control (corn,
barley, and
wheat
middlings) 1.14 0.82
Dried citrus
pulp 1.44 0.78


0.06 0.04

0.06 0.04


MUN,
mg/dl


Glucose,
mg/dl


Insulin,
ng/ml


PUN,
mg/dl


--- 14.0

--- 13.0


12.3

11.8


11.8
19.8
18.9
19.1


48.5

52.0


47.0
50.6
50.3
48.3


13.5
20.1
18.8
19.3


15.3



14.4



15.0



14.7










Table 2-2. Continued


DMI, Milk, Fat, Protein,
--------------------- kg/d -----------


Friggens et al. (1995), 18 lactating cows
Beet pulp --- 14.3 0.60
Beet pulp :
Grain (50:50) --- 14.9 0.57
Grain (barley
and corn) --- 14.5 0.58
Lees et al. (1990), 28 lactating cows
Beet pulp
low CP 14.4 20.6 0.80
Beet pulp
high CP 14.6 23.3 0.95
Maize
low CP 12.0 21.7 0.62
Maize
high CP 12.4 24.5 0.65
Leiva et al. (2000), 11 lactating cows
Citrus pulp diet 20.9 31.3 1.11
Hominy diet 21.4 32.8 1.12
Maiga et al. (1995), 40 lactating cows
Control 23.1 31.9 1.09
Fat (2% tallow) 24.3 33.7 1.22
Molasses + fat 24.5 33.7 1.15
Dried whey + 24.5 34.0 1.17
fat
Mansfield et al. (1994), 46 lactating cows
Main effect
means
Corn 21.5 32.2 1.18
Beet pulp 20.3 31.9 1.21
Soybean meal 21.1 31.9 1.21
Animal by-
product 20.7 32.1 1.19
McCormick et al. (2001), 32 lactating cows
0% sucrose +
solvent
soybean meal 22.8 39.3 1.22
5% sucrose +
solvent
soybean meal 23.1 39.8 1.26
0% sucrose +
expeller
soybean meal 22.8 39.9 1.34
5% sucrose +
expeller
soybean meal 22.6 37.5 1.33


MUN,
mg/dl


Glucose, Insulin, PUN,
mg/dl ng/ml mg/dl


0.48

0.51

0.50


0.60

0.70

0.64


0.74

0.85
0.93

0.94
1.01
0.97
0.98





0.97
0.92
0.96

0.93


1.10 21.5


1.14 21.2


1.11 21.3


Reference
and Treatment


18.3


19.3


16.7


19.4










Table 2-2. Continued
Reference DMI, Milk, Fat, Protein,
and Treatment ---------------- kg/d ---------
Nombekela and Murphy (1995), 24 lactating cows


Control (starch) 19.0 28.4 0.96
Sucrose 19.1 29.3 0.97
Ordway et al. (2002), 34 transitioning cows
prepartum
Ground corn 16.0 -
2.7% sucrose 16.5 -
postpartum
Ground corn 22.1 45.8 ---
2.7% sucrose 22.7 45.6 ---
Sannes et al. (2002), 16 lactating cows
Starch 25.7 34.3 1.33
Sucrose 25.5 33.2 1.27
Solomon et al. (2000), 20 lactating cows
High starch 20.0 35.5 1.18
High starch +
extruded
soybeans 22.0 38.3 1.26
High pectin 20.3 34.6 1.16
High pectin +
extruded
soybeans 20.8 38.2 1.26
Valk et al. (1990), 45 lactating cows
Beet pulp 1 --- 25.8 1.07
Maize 1 --- 28.4 1.11
Beet pulp 2 --- 30.9 1.29
Maize 2 --- 31.6 1.17


Beet pulp +
Maize 2
Van Horn et al.
43.1% citrus
with urea
8.0% citrus
with urea
43.1% citrus
with
soybean meal
8.0% citrus
with
soybean meal


--- 30.8 1.24
(1975), 36 lactating cows


1.07
1.03

1.05


1.09
1.01


1.07

0.89
0.98
1.02
1.03

1.02


MUN,
mg/dl


Glucose, Insulin, PUN,
mg/dl ng/ml mg/dl


0.96
0.95


--- 66.3 0.64
--- 69.3 0.76

--- 55.8 0.23
--- 56.7 0.25


--- 13.9
--- 13.8


13.6


15.3
13.7


15.4


17.3 16.6 0.69 0.56


17.5 17.8 0.64


20.1 18.3 0.81


0.60


0.65


20.0 19.6 0.67 0.70














CHAPTER 3
EFFECTS OF NONFIBER CARBOHYDRATE SOURCE AND PROTEIN
DEGRADABILITY ON LACTATION PERFORMANCE OF HOLSTEIN COWS

Introduction

Collectively, carbohydrates make up 65 to 75% of the diets of lactating dairy cattle.

Dietary carbohydrate is comprised of fiber (NDF) and nonfiber (NFC) fractions.

Nonfiber carbohydrates may provide 30 to 45% of the diet on a dry matter (DM) basis.

Although NFC has been represented as a single value for feeds or diets, the type of

carbohydrates in this fraction can vary greatly. For example, the NFC in corn grain is

mostly starch (65 to 70% of DM), citrus pulp provides sugar (12 to 40% of DM) and

neutral detergent-soluble fiber (NDSF) (25 to 44% of DM), and sugar (mono- and

oligosaccharides) predominates in molasses (Hall, 2002). The dietary complement of

NFC has the potential to alter the supply of metabolizable nutrients to the animal because

NFC differ in digestion and fermentation characteristics. In vitro fermentation of

sucrose, starch, and pectin resulted in different organic acid profiles (Strobel and Russell,

1986), and in maximal microbial protein yields (Hall and Herejk, 1999). Unlike other

NFC, maltose and starch may be digested by mammalian enzymes; monosaccharides and

the digestion products may be absorbed in the small intestine.

Perhaps because of differences in digestion products, the NFC complement of the

diet has the potential to alter feed intake, milk production and composition of milk.

Dietary inclusion of feeds with greater contents of pectin have increased intake (Valk et

al., 1990; Lees et al., 1990; Chester-Jones et al., 1991). Compared to starch, pectin-rich









feeds have decreased milk yield (Van Horn et al., 1975; Leiva et al., 2000; Broderick et

al., 2002b) and yield and percentage of milk protein (Mansfield et al., 1994; Leiva et al.,

2000; Solomon et al., 2000; Broderick et al., 2002b). Milk fat percentage was increased

(Van Horn et al., 1975; Lees et al., 1990; Mansfield et al., 1994) or remained unchanged

with the feeding of pectin-rich diets (Leiva et al., 2000; Solomon et al., 2000).

Supplementation of sugars in place of starchy feeds decreased milk protein percentage

(Nombekela and Murphy, 1995) and yield (Sannes et al., 2002). Still other studies

reported no difference in intake or production as the dietary NFC profile changed

(Fegeros et al., 1995; Malestein et al., 1984).

The objective of this study was to evaluate the effects of altering the dietary

complement of NFC at two different dietary concentrations of ruminally undegradable

protein (RUP) on lactation performance, as well as on blood and ruminal measures.

Materials and Methods

Cows, Diets, and Facilities

Thirty eight multiparous Holstein cows (six ruminally fistulated, 10 cm i.d., Bar

Diamond, Inc. Parma, ID) (82 19 days in milk, average bodyweight of 614 56 kg)

were assigned randomly to a series of dietary treatments in a partially balanced,

incomplete Latin square design with three 21-d periods (14 d for acclimation and 7 d for

sample collection). In the second period the cows received a 28-d acclimation to diets

due to technical difficulties with the feeding system. In the 3 x 2 factorial arrangement of

treatments, the three NFC dietary treatments were starch (ST), soluble fiber plus sugar

(SF), or sugar (SU), achieved by altering the proportions of ground corn, citrus pulp,

liquid molasses, and sucrose included in the diet. Two concentrations of degradable

protein were achieved by supplementing with 48% soybean meal (-RUP) or with a









combination of expeller soybean meal (SoyPLUS; West Central Soy, Ralston, IA) and

48% soybean meal (+RUP). All diets were formulated to contain similar basal

concentrations of forage (corn silage and sorghum silage), to be isonitrogenous, and to

contain similar concentrations of total NFC and NDF (Table 3-1). Analysis of nutrient

contents of the total mixed rations (TMR) indicated that percentages of NDF differed by

NFC source with SF diets containing more NDF than SU diets (P < 0.01). Percentages of

CP in the TMR were greater for cows fed -RUP diets as compared to +RUP (P = 0.02)

and for cows fed SU diets as compared to those consuming SF (P < 0.05). However, the

differences in measured percentages for NDF and CP in the diets were small (Table 3-1),

with the average difference from the mean values of 0.33% and 0.85% of diet DM for CP

and NDF contents, respectively. The RUP diets differed from each other by an average

of 0.57% CP on a DM basis. Cows were fed individually with diets offered in ad libitum

amounts twice daily (at 0600 and 1300 h) through Calan gates (American Calan,

Northwood, NH). Cows were milked three times each day at 0500, 1300, and 2100 h.

The experiment was conducted at the University of Florida Dairy Research Unit,

Hague, Florida, from January to March 2002. Cows were housed in an open-sided, free-

stall barn bedded with sand and equipped with fans and misters. Animals were

maintained under protocols approved by the University of Florida Institutional Animal

Care and Use Committee.

Sample Collection and Analyses

Amounts of diets fed and refused were recorded daily with subsamples of the TMR

and orts obtained for each individual cow during the seven day collection phase of each

period. Two to three grams of TMR and orts samples were dried in a forced-air oven at

105C until a constant weight was achieved to determine DM content. Daily dry matter









intake (DMI) was calculated for each animal. The remainders of the samples were

individually dried at 550C in a forced-air oven and ground to pass the 1-mm screen of a

Wiley mill (A.H. Thomas, Philadelphia, PA) prior to compositing. All TMR and ort

samples were composite on a DM basis by cow by period.

Composited diet samples were analyzed for DM (105C for 8 h) and organic matter

(OM) (512C for 8 h). Neutral detergent fiber was measured using heat-stable, a-

amylase (Goering and Van Soest, 1970; Van Soest et al., 1991) and was not corrected for

ash content in order to retain samples for further analysis. Starch, sugar (80% ethanol-

soluble carbohydrate), and NDSF contents of the feed and orts were determined as

described by Hall et al. (1999). Crude protein (CP) as N x 6.25 was determined by

micro-Kjeldahl using an aluminum block digester (Gallaher et. al., 1975) and an

autoanalyzer (ALPKEM Corporation, Method Number A303-S071). The CP contents of

80% ethanol-insoluble residue and NDF (NDFCP) were determined by a modification of

a Kjeldahl N procedure (AOAC, 1990) in which a digestion mixture of 96% Na2SO4 and

4% Cu2SO4 was used in the digestion and distilled ammonia was recovered in a 4% boric

acid solution (Pierce and Haenisch, 1947).

Milk weights were recorded for all milkings during the collection period and

samples were collected on d 15, 17, and 19 from all three daily milkings. All milk

samples were analyzed by Lancaster DHIA Labs (Lancaster, PA). Milk samples were

analyzed for fat and protein using mid-infrared technology (Model B-2000, Bentley

Instruments, Chaska, MN). Milk urea nitrogen (MUN) was analyzed by an enzymatic

and colorimetric method (Model Chemspec 150, Bentley Instruments, Chaska, MN).

Somatic cell count (SCC) was measured by laser counting technology (Model









Somacount 500, Bentley Instruments, Chaska, MN). Production of fat (3.5%)- and

protein-corrected milk (3.5% FPCM) was calculated by the following equation (derived

from Tyrrell et al., 1965):

3.5% FPCM kg/d =

(12.82 x fat in kg/d) + (7.13 x protein in kg/d) + (0.323 x milk in kg/d).

Feed efficiency was calculated as 3.5% FPCM divided by DMI. Efficiency of nitrogen

utilization was determined by the following equation:

Milk N / Intake N =

(milk kg x (milk protein% / 6.38)) / (DMI kg x (diet CP% / 6.25)).

The concentration of net energy of lactation per unit of DMI was estimated by the

following equation (NRC, 2001) with all milk measures expressed terms of per cow per

day:

NEL Mcal/kg of DMI =

[(0.08 x BWo.75 kg) + ((0.0929 x milk fat %) +(0.0547 x milk crude protein %) +0.192) x

milk kg)] / DMI kg.

For the purpose of comparisons among treatments, it was assumed that energy required

for growth, reproduction, and repletion of reserves were minor contributors to energy

demands of the cattle on this study.

Blood samples (-10 ml) were collected from individual cows on d 15 and 17 of

each period by coccygeal venipuncture into Vacutainer tubes (Becton Dickinson,

Franklin Lakes, NJ) containing sodium heparin, which were immediately placed on ice.

Duplicate samples were transferred into capillary tubes and centrifuged in a micro-

capillary centrifuge (I.E.C. MB Centrifuge) to determine hematocrit and plasma protein.









Hematocrit values were measured on whole blood with a Damon micro-capillary reader

(I.E.C. Cat. No 2201). Plasma protein content was measured using a Schuco

refractometer (Model 5711-2020). Samples were centrifuged at 1916 x g for 30 min at

5C to separate plasma, which was transferred to vials and frozen at -200C until analysis.

An autoanalyzer (Technicon Instruments Corp., Chauncey, NY) was used to

measure plasma urea N (PUN) (a modification of Marsh et al., 1965 as described in Bran

and Luebbe Industrial Method #339-01) and plasma glucose (a modification of

Gouchman and Schmitz, 1972 as described in Bran and Luebbe Industrial Method #339-

19). Plasma insulin was analyzed with a double antibody radioimmunoassay procedure

described by Soeldner and Sloane (1965) and modified by Malven et al. (1987). A

Packard auto gamma counter (model B-5005) measured bound radioactivity in tubes.

In Situ Ruminal Incubations

Extent of DM and NDF disappearance of sorghum silage was measured on d 16,

17, and 18 of each period by the dacron bag technique (Nocek, 1988) using the ruminally

cannulated cows. At the beginning of the study approximately 25 kg of sorghum silage

was collected and dried at 550C for 48 h, and ground to pass a 2-mm screen (Wiley mill,

A.H. Thomas, Philadelphia, PA). Approximately 5.0 g (air dry) was weighed into pre-

weighed polyester bags (10 x 20 cm) with an average pore size of 53 + 10 [tm (Bar

Diamond, Inc., Parma, ID). Duplicate bags were inserted into a nylon mesh bag, which

was inserted into the rumen via the rumen cannula, at intervals of 0, 6, 12, 18, 24, 30, and

48 h. All bags were removed simultaneously. The mesh bags were weighted (- 1kg) to

keep them submerged in the rumen contents. Following removal, bags were submerged

in cold water and rinsed continuously until the water was clear. Bags were then rinsed in

a washing machine on the delicate/cold cycle (Kenmore 70 series, Heavy Duty, Super









Capacity, Sears, Roebuck and Co., IL). Bags were dried in a forced-air oven at 550C for

48 h, and weighed to determine DM residue. The residue was analyzed for NDF

(Goering and Van Soest, 1970; Van Soest et al., 1991) using heat-stable, a-amylase and

corrected for ash content. The potentially digestible fraction and rate of disappearance of

the sorghum silage could not be determined because the curve describing sample

disappearance did not plateau by the end of the incubation period (48 h). Consequently,

bags representing treatments were compared within hour.

Ruminal Fluid Sampling and Analysis

Ruminal fluid samples were collected via ruminal cannulae from the six ruminally

cannulated cows on d 20 of each period. Starting prior to feeding and continuing hourly

for the next 13 h, ruminal fluid (-500 mL) was collected from the cranial, ventral and

caudal areas of the rumen. Samples were capped, inverted to mix, and pH measured

immediately with an electronic pH meter (Fisher Scientific, Accumet Model 15). For

each sample, a subsample of 40 ml was acidified with 1 ml of 50% sulfuric acid and

centrifuged at 5400 x g for 20 min. The supernatant was collected and frozen at -20C

until analysis for volatile fatty acids (VFA) by gas chromatography (4% carbomax

80/120 BDA column, Supelco Inc., Bellefonte, PA) (Autosystem XL gas chromatograph,

Perkin Elmer Inc., Norwalk, CT). For analysis, samples were thawed at room

temperature (approximately 23C) and centrifuged at 5000 x g for 30 min and filtered

with a high affinity protein syringe-driven filter unit (Millex SLAA025LS, Fisher

Scientific, Pittsburg, PA). The gas chromatograph was set to a flow rate of 30 ml/min of

N, an injection port temperature of 200C, oven at 1900C, and the flame ionizing detector

at 4500C.









Due to multiple health disorders not related to the study, one of the cannulated

cows was removed from the study in the third period and was not used for any sampling

in that period. Therefore, data for ruminal measures during the third period are for five

cows.

Statistical Analysis

In all analyses, terms including "cow" were treated as random variables. Average

values per cow per period for TMR composition, feed intake, milk production, milk

composition, plasma urea nitrogen, plasma glucose, plasma insulin, and in situ substrate

disappearance by hour were analyzed by the MIXED procedure of SAS (1996). Data

were analyzed according to the model:

Y ijkl= [ + Ci + Pj + Nk + Ri + NRkl + sijkl

t = overall mean,

Ci = effect of cow (i = 1, 2, ...38),

Pj = effect of period (j = 1, 2, 3),

Nk= effect of NFC treatment (k = ST, SF, SU),

Ri = effect of RUP treatment (1 = +RUP, -RUP),

NRkl = effect of interaction of NFC with RUP treatments, and

ijkl = residual error.

Although reported as pH, ruminal pH was analyzed as hydrogen ion concentration

(Murphy, 1982). Ruminal hydrogen ion concentration and VFA data were analyzed as

repeated measures by the MIXED procedure of SAS (1996) with the model:

Y ijklm = A + Ci(PjNkRi) + Pj + Nk + Ri + NRkl + Hm + PHjm + RHlm + NHkm +

NRHklm+ Eijklm

[t = overall mean,









Ci(PjNkRi) = effect of cow within period and diet (i = 1, 2, 3, 4, 5, 6),

Pj = effect of period (j = 1, 2, 3),

Nk= effect of NFC treatment (k = ST, SF, SU),

R = effect of RUP treatment (1 = +RUP, -RUP),

NRkl = effect of interaction of NFC with RUP treatments,

Hm= sampling hour (0, 1... 12),

PHjm = interaction of period and sampling hour,

RHim= interaction of RUP treatment and hour,

NHkm= interaction of NFC and hour,

NRHklm = interaction of NFC, RUP and hour,

Eijklm = residual error.

Results are reported as least squares means. The orthogonal contrasts performed

were ST vs. SF+SU and SF vs. SU for effect of NFC and interaction of NFC and RUP.

Mean separation was performed using the Tukey-Kramer adjustment. Significance was

declared at P < 0.05, and tendency at 0.05 < P < 0.10.

Results and Discussion

Intake and Lactation Performance

The NFC and RUP treatments and their interaction affected various measures of

performance including DMI and production and composition of milk. Dry matter intake

differed by NFC treatment, with cows consuming more on SU than on SF, and cows

consuming ST tending to have greater intakes than those receiving the other NFC diets

(Table 3-2). Definitive information is lacking regarding the impact of changing the

complement ofNFC on DMI. Substitution of sugars for starch has increased (Broderick

et al., 2002a) or did not change (Nombekela and Murphy, 1995; Ordway et al., 2002)









intake in dairy cattle. Increases in dietary concentrations of NDSF at the expense of

starch increased (Lee et al., 1990; Chester-Jones et al., 1991), decreased (Valk et al.,

1990; Broderick et al., 2002b), or did not affect (Van Horn et al., 1975; Leiva et al.,

2000) DMI. Changes in passage rate (Piwonka et al., 1994) or fiber digestibility (Heldt et

al., 1999) with varying NFC source may offer partial answer as to why the changes occur.

In the present study, intake was unaffected by protein degradability.

As designed, intake of sugars, starch, and NDSF changed with varying NFC

treatment. Cows fed treatments ST, SF, and SU had the greatest intakes of starch, NDSF,

and sugars, respectively (Table 3-2). Cows tended to consume more starch and

consumed more NDSF when fed SF diets than SU diets. Cows consuming the ST

treatment gave the smallest sugar and NDSF intakes compared to the other NFC

treatments. Intake of NDF did not differ by treatment. However, there were some

unexpected differences in intakes of total NFC, ash, and CP. Cows consuming ST and

SU diets had greater intakes of total NFC as compared to those consuming SF diets.

Intakes of ash were about 0.2 kg/d greater for cows consuming SU diets as compared to

those consuming SF diets. Protein intake differed by RUP treatment, with cows offered -

RUP diets consuming more CP, which may be due in part to the reduced CP% of DM of

the +RUP diets. Animals offered SU consumed more CP and NDFCP than those

receiving SF. Diets were formulated to be isonitrogenous and to contain a greater

concentration of CP (-17%) than measured (Table 3-1). The differences in dietary CP

content could relate to undetected changes in forage or concentrate ingredients.

Alternatively, the mineral mix provided 0.9% of diet DM as urea; hydrolysis of the urea

and its release as ammonia as it was blended with the silage might result in less than









expected measured CP concentrations. The MUN values observed for the cows suggest

that degradable protein was not limiting in the diets (Table 3-3).

Although replacing starch with sugars has sometimes increased intake, a milk

production response has not always followed (Broderick et al., 2002a; Broderick and

Radloff, 2002). In contrast, an increase in production with sugar supplementation

without a concomitant increase in intake has been reported (McCormick et al., 2001).

More consistent patterns of decreased milk yield response with replacing starch sources

with sources ofNDSF have been reported (Van Horn et al., 1975; Leiva et al., 2000;

Broderick et al., 2002b). Milk composition response has varied, with protein usually

decreasing with the inclusion of sugars (Nombekela and Murphy; 1995; Maiga et al.,

1995; Sannes et al., 2002) and pectin-rich feeds (Mansfield et al., 1994; Leiva et al.,

2000; Solomon et al., 2000; Broderick et al., 2002b). The milk fat response also has

varied with NFC source, with pectin-rich diets (Lees et al., 1990; Mansfield et al., 1994)

and sugars (Broderick et al., 2002a) increasing fat concentrations or amounts. Studies

also have reported no effect on milk fat when feeding pectin-rich diets compared to those

high in starch (Leiva et al., 2000; Solomon et al., 2000).

In the present study, 3.5% FPCM tended to differ among NFC with cows

consuming SU having greater yields as compared to SF (Table 3-3). There was a

numerical decrease in 3.5% FPCM yield for ST and an increase for SU and SF with the

+RUP treatment, which gave rise to a significant NFC x RUP interaction. Milk fat yield

was not affected by treatment. Milk protein yield differed by NFC with cows fed ST

having greater protein yields than SU and SF. This is consistent with Broderick et al.

(2002b) where cows fed high moisture or cracked corn diets produced more milk protein









than those consuming diets with dried citrus pulp. Cows fed SU diets tended to produce

greater amounts of milk protein as compared to those fed SF. Milk urea N concentration

was greater in cows fed ST than SU and SF. There was also a tendency for cows fed -

RUP to have greater MUN concentrations.

The estimated net energy of lactation (NEL mcal/kg) of the diets differed for the

interaction ofNFC x RUP and tended to differ by NFC source (Table 3-2). The NEL

content of ST tended to be less than for SF and SU. Indirectly, this is consistent with the

work of Ariza et al., (2001) that reported increased efficiency of microbial N yield per kg

of OM truly fermented on a substrate containing more sugar and NDSF than on one

containing more starch. Dietary NEL was decreased for ST with the addition of +RUP,

while SU and SF had an increased NEL when +RUP was fed. Little work has been done

on NEL determination of non-starchy concentrate or by-product feeds (H. Tyrrell,

personal communication).

Feed efficiency differed for the interaction of NFC x RUP. Feed efficiency of cows

fed +RUP diets decreased when fed ST, but increased when fed SU or SF diets (Table 3-

3). This suggests that the cows fed the ST diet did not require additional RUP for milk

production, which could have been the case if there was a greater ruminal yield of

microbial protein in cows consuming ST or if other nutrients became limiting before

protein. Nitrogen efficiency (Milk N/Feed N) tended to vary by NFC source with greater

values for cows fed the ST diets as compared to those fed SF and SU diets. The greater

microbial protein yields previously reported for starch as compared to sucrose (in vivo;

Sannes et al., 2002) and to sucrose and citrus pectin (in vitro; Hall and Herejk, 2001)









could partially explain the greater protein yields and differences for feed and N

efficiencies for ST in this study.

Plasma and Ruminal Measures

Plasma protein concentration and hematocrit (Table 3-3) were not affected by

treatment and were not used to adjust the concentrations of metabolites in the blood.

Plasma glucose and insulin concentrations were greater for cows fed SU as compared to

SF. Increases in blood glucose have been noted previously in dry cows with the inclusion

of 2.7% sucrose in the diets (Ordway et al., 2002). Plasma urea N followed the same

pattern as MUN increasing with -RUP as compared to +RUP, and with ST greater than

SU and SF.

In the current study, mean ruminal fluid pH differed little by dietary treatment. For

+RUP as compared to -RUP, the pH was numerically greater for SU, and smaller for ST

and SF, with SU-RUP showing a visibly decreased pH over time than the other

treatments (Table 3-3, Figure 3-1). Ruminal pH was affected by sampling hour (P <

0.01) and NFC x hour (P = 0.01) (Figure 3-1). Although pH differences were not

detected in the current study (Table 3-4), several studies have shown decreased ruminal

pH with the addition of sugars to the diet (Khalili and Huhtanen, 1991; Moloney et al.,

1994; Maiga et al., 1995; Martin et al., 2000). In contrast, Heldt et al. (1999) found that

feeding starch decreased pH more than feeding glucose, fructose and sucrose.

Several effects of NFC source and RUP supplementation, as well as hour of

sampling, were detected for ruminal measures. Total VFA concentrations changed over

time (P < 0.01) (Figure 3-2), but were not affected by dietary treatment (Table 3-4).

Similarly, a number of studies have not detected a change in total ruminal VFA

concentration with varying NFC complement (Mansfield et al., 1994; Piwonka et al.,









1994; Leiva et al., 2000; Sannes et al., 2002). Ruminal acetate molar percentage changed

over time (P < 0.01) and tended to differ by NFC x hour (P = 0.07). The mean molar

percentage of acetate tended to be greater in the ruminal fluid of cows fed SF diets

compared to that of cows fed SU diets. This change in acetate was not associated with an

increased milk fat yield for cows consuming SF diets. Propionate molar percentage

differed only by time of sampling (P < 0.01). These findings differ from those of an in

vitro fermentation study that reported increased propionate yields from starch

fermentation as compared to that of citrus pectin fermentation, but agrees with their

findings of increased acetate concentrations from citrus pectin as compared to sucrose

(Strobel and Russell, 1986). Molar percentage of butyrate differed by NFC and hour (P

< 0.01) with SU and SF greater than ST, and SU greater than SF. This is consistent with

numerous studies (Strobel and Russell, 1986; Khalili and Huhtanen, 1991; Moloney et

al., 1994; Friggens et al., 1998; Heldt et al., 1999; Broderick and Radloff, 2002) where

the greatest increase in butyrate was demonstrated with feeding sugars as compared to

starch. Butyrate molar percentage was also affected by NFC x hour (P = 0.02), RUP x

hour (P = 0.04), and NFC x RUP x hour (P = 0.05). The molar percentage of branch

chain VFA (BCVFA) differed among NFC treatments and by sampling hour (P < 0.01)

with ST greater than SU and SF, and SF greater than SU. This is consistent with a

number of studies that have reported a decrease in BCVFA when replacing corn with

sucrose (Broderick and Radloff, 2002; Broderick et al., 2002a; Sannes et al., 2002). In

those studies the reported decreases in BCVFA were accompanied by decreases in

ruminal NH3-N.









The acetate to propionate ratio was greater (tacetate4,propionate) for +RUP diets

and SF diets gave greater values than did SU. Also, SU and SF tended to have greater

acetate to propionate ratios than ST. This is a result of the increased acetate molar

percent from the SF feeding. These findings are consistent with research that showed

that fermentation of pectin, the predominant soluble fiber in citrus pulp, yields

considerably more acetate than propionate compared to other NFC (Strobel and Russell,

1986).

The proportion of residual DM and NDF in situ differed by NFC source for several

of the sampling hours (Table 3-5). In hours 18 through 30 cows consuming ST and SF

both had less residual DM and NDF as a percentage of the original substrate than did SU.

This result is in contrast to studies where digestibility of NDF increased with sugar

supplementation in vivo (Piwonka et al., 1994; Heldt et al., 1999), but in agreement with

digestibility increases noted when feeding pectin-rich feeds (Ben-Ghedalia et al., 1989;

Van Vuuren et al., 1993b) and decreases in rate of NDF digestion when fermenting

glucose, attributed to a proteinaceous inhibitor (Piwonka and Firkins, 1996). In the

present study, the low pH noted on SU-RUP may have had a negative effect on ruminal

digestion, resulting in SU exhibiting more depressed ruminal digestibilities than the other

NFC treatments. Alternatively, the decreased BCVFA noted for SU as compared to other

NFC treatments may have made this nutrient limiting for fiber utilizing bacteria, and thus

limited their ability to grow and digest fiber. Protein degradation products have been

shown to be stimulatory to fibrolytic bacteria (Stewart and Bryant, 1988). In situ

disappearance of DM and NDF was also affected by RUP in hours 12 and 24 (and 30 for

DM). The -RUP diets had a greater percentage of remaining DM and NDF when









compared to the +RUP. Additionally, there were several significant interactions of NFC

with RUP in hours 6 through 30. In these sampling hours, less DM and NDF were

recovered on +RUP for ST and SU, whereas with SF, more DM and NDF remained on

+RUP. This suggests that the supplementation of +RUP had a positive effect on ruminal

digestion for the ST and SU diets and negative for SF. If RDP was limiting in the

SF+RUP diets NDF digestion may have been reduced, however, such a nutrient

limitation does not appear to be supported by the MUN or PUN results. The source of

NFC together with sufficiency of RDP has been shown to vary in its effects on

digestibility of organic matter and NDF (Heldt et al., 1999).

Conclusions

Varying dietary NFC source together with degradability of dietary protein altered

intake, lactation performance, and blood and ruminal measures in lactating dairy cows.

The findings of this study suggest that the lactation performance of dairy cattle may be

similar when starch or sugars are the main NFC source, but may be reduced when sugars

and soluble fiber, as supplied by citrus pulp, are the main NFC source. This response

may be due in part to the decreased intakes of cows consuming SF diets. Despite

differences in lactation performance, feed efficiency was similar for the starch-, sugar-

and pectin-rich diets. That feed efficiency and 3.5% FPCM yields on the sugar and citrus

diets improved and those on the starch diets declined with increasing RUP, suggest that

differences in metabolizable protein yields as affected by the NFC portion of the diets can

be supplemented through modification of the dietary protein component. Curiously,

estimates of NEL values of the diets suggest that the diets with the greatest starch contents

had relatively lesser energy contents.









Compared to the other NFC treatments, consumption of sugars appeared to modify

ruminal protein degradation or metabolism. In this study and other studies cited herein,

the greatest molar percentage of butyrate and smallest BCVFA molar percentage or

concentration have been reported for cows consuming diets containing sugars. Possible

explanations for the decreases in ammonia (from other studies) and BCVFA values noted

for molasses and sucrose feeding include: decreased RDP or microbial degradation in the

rumen, increased usage of BCVFA and NH3-N by sugar-utilizing microbes, or increased

rate of passage from the rumen. The decreased in situ disappearance of NDF noted on

the sugar-rich diet in this study may be related to competition for BCVFA and NH3-N

between fiber-utilizing and sugar-utilizing microbes. The potential effect of decreased

ruminal pH on fiber digestion relative to other diets only applies to the SU-RUP

treatment. That ruminal NDF disappearance increased on the starch and sugar diets and

decreased on the citrus diet with the addition of RUP is not so readily explained. There is

limited discussion of root causes of non-pH-associated changes in fiber digestion in the

literature. This area requires further evaluation.

The results of this study indicate that changing dietary NFC together with protein

degradability can alter lactation performance, possibly through modification of the

metabolizable nutrient supply received by the cow. Further work is needed to determine

the optimal concentrations of NFC types, in combination with protein degradability and

other dietary components, required to promote efficient lactation performance by dairy

cows.










Table 3-1. Ingredient and chemical composition of diets.
Ingredient, Diets'
% of diet DM ST-RUP ST+RUP SF-RUP SF+RUP SU-RUP SU+RUP
Corn silage 25.9 25.7 25.6 25.2 26.2 25.9
Sorghum silage 11.9 11.8 11.7 11.6 12.0 11.9
Cottonseed hulls 3.9 3.8 3.9 3.8 3.9 3.9
Whole cottonseed 13.6 13.3 13.6 13.4 13.8 13.5
48% Soybean meal 14.6 5.8 15.8 6.4 16.6 6.7
SoyPLUS2 --- 9.7 --- 10.5 --- 10.9
Corn meal 20.9 20.7 3.8 3.8 1.9 1.9
Citrus pulp 3.8 3.8 20.7 20.4 9.8 9.7
Molasses --- --- --- --- 7.1 7.1
Sucrose --- --- --- --- 3.3 3.2
Limestone 1.2 1.3 0.6 0.7 1.1 1.1
Mineral mix 4.2 4.2 4.3 4.2 4.3 4.3
Measured component,
% of diet DM
CP 16.4 15.4 16.3 16.2 17.0 16.5
NDF 39.1 39.6 40.7 40.5 38.5 38.1
NDFCP 3.6 4.0 3.8 4.0 3.8 4.0
Sugar 4.1 4.3 7.6 8.0 13.1 13.5
Starch 23.4 23.6 14.8 15.3 13.4 13.0
NDSF4 1.9 1.9 5.5 5.3 4.0 3.3
Sum ofNFC5 29.4 29.8 27.8 28.5 30.5 29.8
Ash 6.4 6.3 6.6 6.5 7.0 6.9
1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses +
sucrose, -RUP = soybean meal, and +RUP = expeller soybean meal.
2 West Central Soy, Ralston, IA.
SMineral mix contained (DM basis) 23.9% CP, 1.12% Fat, 1.16% ADF, 9.51% Ca, 0.89% P,
1.51% S, 21.7% NPN, 1.99% Cl, 1.99% Salt, 3.0% Mg, 3.19% K, 8.07% Na, 680 PPM Fe, 1644
ppm Zn, 1195 ppm Mn, 498 ppm Cu, 25.1 ppm Co, 25.5 ppm I, 7.67 ppm Se, 147 KIU/kg
vitamin A, 42.8 KIU/kg vitamin D3, 768 KIU/kg vitamin E.
4 Neutral detergent-soluble fiber.
5 starch + sugar + NDSF.

















6.4

6.3

6.2

. 6.1

a 6

Z 5.9

5.8

5.7

5.6


0 2 4 6 8 10 12 14

Sampling Hour


Figure 3-1. Temporal patterns of ruminal pH by dietary treatment.

Cows were fed following the 0 sampling hour.


Acetate


Propionate


ZU
r1~~~


1 2 3 4 5 6 7 8 9 10 11 12 13


Butyrate


--C.-
pO~ A- r
-o


1 2 3 4 5 6 7 8 9 10 11 12 13

BCVFA


o- ---

--


1 2 3 4 5 6 7 8 9 10 11 12 13


1 2 3 4 5 6 7 8 9 10 11 12 13


Figure 3-2. Acetate, propionate, butyrate and BCVFA by sampling hour for ST-RUP 0,

ST+RUP *, SF-RUP A, SF+RUP A, and SU-RUP 0, and SU+RUP @.

Cows were fed following the hour 1 sampling.



















Table 3-2. Nutrient intake by dietary treatment.
Diets' P values Contrasts5
ST- ST+ SF- SF+ SU- SU+ NFC x
Item RUP RUP RUP RUP RUP RUP SED NFC RUP RUP 1 2 3 4
DMI2, kg/d 25.0 25.2 23.9 23.5 25.2 24.6 0.79 0.02 0.56 0.65 0.09 0.03 0.36 0.84
CP intake, kg/d 4.15ab 3.97ab 3.98ab 3.84a 4.38b 4.11b 0.15 0.01 0.04 0.82 0.84 0.01 0.88 0.54
NDF intake, kg/d 9.62 10.0 9.70 9.48 9.69 9.57 0.35 0.62 0.94 0.41 0.34 0.89 0.19 0.84
Starch intake, kg/d 5.83a 6.03a 3.52b 3.41b 3.33b 3.14b 0.19 <0.01 0.78 0.31 <0.01 0.09 0.13 0.76
NDSF intake, kg/d 0.54a 0.52" 1.31bc 1.25bc 1.02ac 0.91ac 0.20 <0.01 0.61 0.95 <0.01 0.03 0.80 0.85
Sugar intake, kg/d 1.05" 1.05" 1.79b 1.72b 3.31 3.44c 0.10 <0.01 0.80 0.36 <0.01 <0.01 0.77 0.15
NFC3 intake, kg/d 7.47" 7.53a 6.65b 6.40b 7.64" 7.47" 0.32 <0.01 0.55 0.76 0.02 <0.01 0.48 0.86
Ash intake, kg/d 1.63abc 1.60ac 1.58ac 1.54 1.79b 1.72bc 0.06 0.01 0.25 0.92 0.24 <0.01 0.73 0.86
NEL, Mcal/kg of DMI 1.48b 1.42a 1.48ab 1.55b 1.46ab 1.51ab 0.04 0.10 0.49 0.05 0.07 0.28 0.02 0.74
a,b,c Means in the same row with different superscripts differ, P < 0.05.
1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses + sucrose, -RUP = soybean meal, and
+RUP = expeller soybean meal.
2 Dry matter intake.
3 Nonfiber carbohydrate intake =starch + sugar + NDSF
4 Estimated net energy of lactation per kg of DMI.
5 1 = ST vs. SU+SF for NFC, 2 = SU vs. SF for NFC, 3 = ST vs. SU+SF for NFC x RUP, and 4 = SU vs. SF for NFC x RUP














Table 3-3. Milk production, milk composition, blood measures, and efficiency measures by dietary treatment.
Diets' P values Contrasts7
ST- ST+ SF- SF+ SU- SU+ NFC x
Item RUP RUP RUP RUP RUP RUP SED NFC RUP RUP 1 2 3 4
Milk, kg/d 41.0a 39.1ab 38.0b 38.6a 40.1ab 40.9ab 1.10 0.01 0.82 0.15 0.33 0.01 0.05 0.94
3.5%FPCM2, kg/d 38.9" 36.8ab 35.7b 37.0ab 38.2ab 38.5ab 1.26 0.06 0.84 0.13 0.53 0.03 0.05 0.58
Feed efficiency3 1.58 1.47 1.51 1.59 1.52 1.56 0.06 0.72 0.90 0.03 0.46 0.78 0.01 0.54
Milk fat, kg/d 1.37 1.30 1.27 1.37 1.38 1.39 0.06 0.26 0.69 0.13 0.51 0.13 0.07 0.36
Milk fat, % 3.35 3.36 3.40 3.67 3.45 3.47 0.11 0.06 0.15 0.16 0.03 0.32 0.33 0.10
Milk protein, kg/d 1.13a 1.06ab 1.01b 0.98b 1.05ab 1.05ab 0.04 <0.01 0.18 0.49 0.01 0.06 0.28 0.60
Milk protein, % 2.80 2.76 2.67 2.64 2.70 2.62 0.03 <0.01 0.02 0.54 <0.01 0.97 0.66 0.30
SCC 2.51 2.78 2.23 2.66 2.75 3.25 0.40 0.15 0.14 0.91 0.75 0.14 0.69 0.91
N efficiency4 0.27 0.26 0.25 0.26 0.24 0.25 0.01 0.06 0.76 0.40 0.03 0.29 0.18 0.83
Hematocrit 28.4 27.6 28.6 28.1 28.1 27.9 0.65 0.54 0.17 0.72 0.55 0.37 0.50 0.64
Plasma protein 7.52 7.68 7.69 7.82 7.77 7.66 0.16 0.36 0.55 0.43 0.17 0.75 0.42 0.29
MUN5, mg/dl 13.6 13.2 13.1 12.1 12.8 12.2 0.58 0.05 0.07 0.66 0.02 0.88 0.48 0.58
Glucose, mg/dl 66.0 66.5 65.0 65.3 67.4 66.9 1.02 0.02 0.87 0.77 0.88 0.01 0.64 0.57
PUN6, mg/dl 15.4" 14.6b 14.3ab 12.8b 14.0b 13.4b 0.80 0.02 0.05 0.70 0.01 0.75 0.80 0.43
Insulin, ng/ml 0.52 0.49 0.46 0.47 0.53 0.54 0.04 0.09 0.73 0.79 0.84 0.03 0.50 1.00
a,b,c Means in the same row with different superscripts differ, P < 0.05.
1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses + sucrose, -RUP = soybean meal, and
+RUP = expeller soybean meal.
2 3.5% fat and protein corrected milk yield.
3 Feed efficiency calculated as 3.5%FPCM divided by DMI.
4N efficiency calculated as Milk N divided by N intake.
5 Milk urea N.
6 Plasma urea N.
7 1 = ST vs. SU+SF for NFC, 2 = SU vs. SF for NFC, 3 = ST vs. SU+SF for NFC x RUP, and 4 = SU vs. SF for NFC x RUP

















Table 3-4. Ruminal fluid measures by dietary treatment.
Diets' P values Contrasts4
ST- ST+ SF- SF+ SU- SU+ NFC x
Measure RUP RUP RUP RUP RUP RUP SED NFC RUP RUP 1 2 3 4
Total VFA,
mM 127 123 129 125 134 124 6.24 0.74 0.13 0.72 0.52 0.66 0.62 0.52
VFA in molar %
Acetate 63.2 66.5 65.0 65.0 62.5 63.3 1.43 0.14 0.12 0.24 0.30 0.08 0.11 0.75
Propionate 21.7 19.8 19.6 19.5 20.9 20.4 1.18 0.32 0.26 0.55 0.38 0.25 0.30 0.84
Butyrate 9.70a 9.07a 10.lab 10.6ab 12.0b 11.7b 0.55 <0.01 0.59 0.36 0.01 0.01 0.33 0.33
BCVFA2 2.98 2.82 2.58 2.31 1.81 1.83 0.37 0.01 0.53 0.86 0.01 0.05 0.93 0.59
A:P ratio3 2.96 3.30 3.25 3.38 3.09 3.17 0.26 <0.01 <0.01 0.04 0.01 0.07 0.25 0.77
Ruminal fluid
pH 5.99 5.98 6.11 6.03 5.83 6.07 0.39 0.26 0.22 0.53 0.53 0.12 0.39 0.43


a',Means in the same row with different superscripts differ, P < 0.05.
1 ST = starch = ground corn, SF = soluble fiber + sugar = citrus pulp, SU =


sugars = molasses + sucrose, -RUP


soybean meal,


and +RUP = expeller soybean meal.
2 Branch chain volatile fatty acids include isobutyrate, methylbutyrate, and isovalerate
3 Acetate to propionate ratio
4 1 = ST vs. SU+SF for NFC, 2 = SU vs. SF for NFC, 3 = ST vs. SU+SF for NFC x RUP, and 4 = SU vs. SF for NFC x RUP














Table 3-5. Residual NDF by hour of in situ incubation and dietary treatment.
Diets' P values Contrasts3
ST- ST+ SF- SF+ SU- SU+ NFC x
RUP RUP RUP RUP RUP RUP SED NFC RUP RUP 1 2 3 4
Remaining NDF %, as a % of initial NDF
02 0.662 0.665 0.663 0.667 0.665 0.664 0.003 1.00 0.96 1.00 0.99 0.99 0.94 1.00
6 0.627"c 0.628" 0.623bc 0.637a 0.631abc 0.615b 0.004 0.04 0.95 <0.01 0.38 0.01 0.90 0.01
12 0.597b 0.565a 0.586ab 0.591b 0.597b 0.579ab 0.008 0.47 <0.01 0.01 0.24 0.89 0.01 0.12
18 0.558ac 0.529b 0.530b 0.558c 0.582c 0.566c 0.008 <0.01 0.20 <0.01 0.01 <0.01 0.01 0.01
24 0.533a 0.489b 0.519ab 0.527a 0.551a 0.518ab 0.012 0.05 <0.01 0.01 0.02 0.19 0.04 0.02
30 0.486"a 0.446b 0.446b 0.487c 0.514c 0.478c 0.011 <0.01 0.07 <0.01 0.04 0.01 0.01 0.01
48 0.402 0.383 0.378 0.396 0.403 0.402 0.010 0.12 0.90 0.05 0.84 0.04 0.05 0.21
Remaining DM %, as a % of initial DM
0 0.762 0.762 0.762 0.762 0.762 0.762 0.001 1.00 0.99 1.00 1.00 1.00 0.99 1.00
6 0.707 0.707 0.702 0.713 0.709 0.695 0.006 0.46 0.73 0.04 0.57 0.24 0.74 0.16
12 0.668 0.630 0.657 0.658 0.664 0.647 0.009 0.36 0.01 0.02 0.19 0.74 0.01 0.17
18 0.621 0.589 0.595 0.619 0.645 0.631 0.008 <0.01 0.09 0.01 0.01 <0.01 0.01 0.01
24 0.593 0.548 0.585 0.588 0.614 0.579 0.013 0.05 0.01 0.03 0.02 0.30 0.09 0.06
30 0.540 0.500 0.507 0.546 0.574 0.534 0.012 0.01 0.03 <0.01 0.01 0.01 0.01 0.01
48 0.456 0.434 0.432 0.452 0.460 0.454 0.012 0.23 0.69 0.07 0.63 0.09 0.08 0.17


soybean meal,


3 1 = ST vs. SU+SF for NFC, 2 = SU vs. SF for NFC, 3 = ST vs. SU+SF for NFC x RUP, and 4 = SU vs. SF for NFC x RUP


a,b,c Means in the same row with different superscripts differ, P < 0.05.
1 ST = starch =ground corn, SF = soluble fiber + sugar = citrus pulp, SU = sugars = molasses + sucrose, -RUP
and +RUP = expeller soybean meal.
2 Hour of fermentation

















APPENDIX A
MILK PRODUCTION, COMPOSITION, AND PLASMA MEASURES

Table A-1. Averages for milk production, fat percent, protein percent, milk urea N
(MUN), and somatic cell count (SCC) by cow, period, and diet. Diets
1 = ST-RUP, 2 =ST+RUP, 3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and
6 = SU+RUP.
Cow Period Diet Milk, kg/d Fat % Protein % MUN, mg/dl SCC
2680 1 3 36.7 3.5 2.9 10.5 6.0
2682 1 2 37.6 2.9 2.5 13.7 5.8
2760 1 6 44.7 3.8 2.6 13.2 0.4
2824 1 5 46.7 3.3 2.4 13.0 5.1
2931 1 6 46.7 3.5 2.6 10.7 3.9
2986 1 2 44.4 2.9 2.8 13.2 0.2
3136 1 3 40.6 3.5 2.6 10.7 0.0
3165 1 2 42.8 3.4 2.9 11.9 0.0
3319 1 1 43.1 3.7 2.9 13.1 0.0
3338 1 6 50.3 3.3 2.3 13.4 6.3
3340 1 5 39.7 3.7 2.5 13.7 4.4
3344 1 5 46.8 2.9 2.5 11.0 5.8
3444 1 2 42.3 2.7 2.7 11.1 4.7
3445 1 6 46.1 3.3 2.6 13.9 6.5
3448 1 4 46.2 3.2 2.4 14.6 0.0
3532 1 3 44.8 3.2 2.6 12.4 0.1
3560 1 4 40.6 3.4 2.7 12.1 1.7
3588 1 5 41.6 3.3 2.9 10.6 4.6
3621 1 1 43.9 3.0 2.7 11.3 0.0
3622 1 4 38.4 3.6 2.6 9.3 1.6
3633 1 3 45.0 3.2 2.4 10.0 0.0
3661 1 2 31.1 3.4 2.8 12.2 1.2
3668 1 1 48.6 3.1 2.3 12.5 1.7
3703 1 2 38.3 4.3 2.9 13.1 3.9
3708 1 4 43.4 4.1 2.4 11.4 2.1
3738 1 4 42.3 3.7 2.4 12.7 1.4
3755 1 3 37.9 3.0 2.4 11.2 2.1
3801 1 1 35.5 3.2 2.7 12.7 5.8
5882 1 5 35.5 3.8 2.6 10.6 0.0
5896 1 4 34.1 3.6 2.4 12.3 0.2
6000 1 1 42.9 3.2 2.6 13.2 1.0
6029 1 4 39.9 4.1 2.7 11.7 0.4
6072 1 3 43.2 3.2 2.7 10.8 1.2
6078 1 1 40.2 3.1 2.3 14.7 0.2
6079 1 2 42.9 2.9 2.8 13.4 0.6
6095 1 6 47.3 3.4 2.7 14.6 0.5











Table A-1. Continued
Cow Period Diet Milk, kg/d Fat % Protein % MUN, mg/dl SCC
6138 1 3 41.9 3.3 2.5 17.2 0.0
6162 1 6 45.4 3.6 2.5 16.0 3.4
2680 2 2 36.3 3.6 3.1 14.0 6.3
2682 2 3 33.0 2.9 2.7 14.9 7.3
2760 2 3 42.3 3.7 2.8 14.3 0.1
2824 2 6 47.3 3.2 2.4 13.3 6.8
2931 2 5 42.7 3.5 2.8 13.5 5.6
2986 2 5 42.7 3.8 3.1 14.7 0.6
3136 2 5 43.7 3.5 2.8 11.1 0.2
3165 2 4 41.0 4.4 3.3 12.6 0.0
3319 2 3 39.6 4.0 3.1 14.7 0.0
3338 2 4 50.7 3.6 2.5 15.3 5.3
3340 2 3 40.4 3.2 2.7 18.1 5.0
3344 2 1 41.1 2.9 2.9 12.8 6.0
3444 2 1 41.2 3.3 3.0 13.2 4.8
3445 2 6 41.0 3.0 2.9 13.5 7.7
3448 2 1 49.5 3.4 2.8 16.0 0.2
3532 2 1 39.9 3.3 2.7 15.5 1.3
3560 2 2 36.4 3.1 3.1 14.3 2.4
3588 2 5 37.7 3.9 3.0 12.9 2.8
3621 2 5 46.9 3.4 2.8 12.6 1.5
3622 2 6 40.5 3.7 2.6 15.1 1.6
3633 2 6 45.6 3.6 2.6 13.0 0.1
3661 2 6 41.2 3.8 2.9 13.1 1.1
3668 2 1 42.2 3.5 2.5 14.4 0.5
3703 2 2 34.1 4.2 3.3 13.0 4.8
3708 2 4 37.7 3.3 2.6 12.8 5.0
3738 2 5 42.3 3.7 2.7 16.4 0.8
3755 2 4 39.4 3.0 2.5 14.5 4.1
3801 2 6 36.3 3.4 2.7 12.3 5.9
5882 2 2 30.8 4.1 3.0 10.5 0.0
5896 2 5 29.7 3.8 2.7 15.5 1.3
6000 2 4 42.1 3.7 2.7 12.9 1.0
6029 2 3 40.7 4.2 2.9 16.6 0.8
6072 2 4 37.7 4.3 3.0 13.1 0.8
6078 2 2 35.2 3.8 2.4 24.7 2.3
6079 2 3 41.8 3.8 2.9 16.6 0.7
6095 2 2 49.9 3.4 2.9 13.5 0.1
6138 2 3 41.1 3.6 2.7 19.2 0.5
6162 2 1 45.0 3.8 2.9 16.0 2.5
2680 3 3 30.6 3.6 2.9 11.0 4.9
2682 3 6 32.0 3.2 2.4 7.6 7.7
2760 3 2 39.6 4.1 2.8 8.7 7.0
2824 3 3 34.4 2.8 2.3 12.9 6.5
2931 3 6 42.2 3.1 2.6 8.7 5.8
2986 3 4 32.2 4.7 2.7 9.6 2.6
3136 3 3 36.2 3.3 2.7 10.3 0.7











Table A-1. Continued


Cow
3165
3319
3338
3340
3344
3444
3445
3448
3532
3560
3588
3621
3622
3633
3661
3668
3703
3708
3738
3755
3801
5882
5896
6000
6029
6072
6079
6095
6138
6162


Period
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3


Diet
2
1
4
3
5
2
2
6
1
2
1
5
4
5
6
3
4
6
2
1
1
1
2
3
4
1
6
6
5
4


Table A-2. Averages for plasma urea nitrogen (PUN), glucose, and insulin by cow,
period, and diet. Diets 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP, 4 = SF+RUP,
5 = SU-RUP, and 6 = SU+RUP.


Glucose,
mg/dl
63.9
67.5
71.6
63.8
70.9
60.8
65.8
66.6
61.8
67.7


Insulin,
ng/ml
0.43
0.50
0.32
0.56
0.59
0.32
0.31
0.41
0.67
0.61


Milk, kg/d
39.1
38.1
37.4
33.5
34.7
39.4
41.9
42.4
38.5
33.4
37.6
39.0
29.0
43.0
36.8
35.3
25.0
26.4
39.7
37.4
34.8
33.7
23.8
30.5
36.3
38.4
38.7
47.2
37.6
38.3


Fat %
3.6
3.4
2.9
3.4
2.7
2.9
3.2
3.2
2.8
2.9
3.3
3.1
3.4
3.2
4.1
3.2
3.7
2.8
3.2
3.2
3.4
3.7
3.8
3.6
3.7
3.6
3.4
3.7
3.3
3.7


Protein %
3.2
3.2
2.4
2.5
2.7
3.0
2.9
2.5
2.7
3.0
3.0
2.7
2.5
2.4
2.7
2.3
2.9
2.4
2.7
2.6
2.9
3.0
2.6
2.4
2.7
2.9
2.8
2.6
2.6
2.5


MUN, mg/dl
12.8
12.3
11.6
13.5
10.7
11.9
11.3
9.7
16.0
10.9
10.6
10.3
10.6
11.6
10.0
11.0
10.1
9.1
14.1
14.7
10.7
12.8
12.9
11.4
13.2
12.2
10.3
11.5
16.3
12.4


SCC
0.8
0.0
6.2
4.5
4.7
4.8
5.8
0.1
0.9
3.1
4.5
2.9
2.5
0.6
3.7
0.3
5.4
6.5
1.9
4.0
5.9
0.0
0.4
3.0
2.6
2.4
4.1
2.4
1.8
3.3


Period
1
1
1


Diet
3
2
6


Cow
2680
2682
2760
2824
2931
2986
3136
3165
3319
3338


PUN,
mg/dl
13.1
15.1
14.7
12.5
12.1
14.2
13.1
18.9
16.0
19.5











Table A-2. Continued
PUN, Glucose, Insulin,
Cow Period Diet mg/dl mg/dl ng/ml
3340 1 5 16.2 64.8 0.54
3344 1 5 11.5 64.9 0.48
3444 1 2 10.9 71.3 0.49
3445 1 6 14.1 69.9 0.56
3448 1 4 13.4 65.0 0.40
3532 1 3 13.7 60.7 0.46
3560 1 4 10.6 70.2 0.58
3588 1 5 14.9 68.0 0.59
3621 1 1 14.8 66.1 0.49
3622 1 4 9.6 67.6 0.33
3633 1 3 10.3 60.8 0.43
3661 1 2 15.1 75.1 0.52
3668 1 1 15.2 65.6 0.61
3703 1 2 18.2 64.4 0.76
3708 1 4 16.5 65.0 0.47
3738 1 4 15.0 63.0 0.37
3755 1 3 15.2 61.6 0.51
3801 1 1 14.4 65.1 0.67
5882 1 5 10.3 61.5 0.50
5896 1 4 12.0 65.0 0.52
6000 1 1 13.5 66.4 0.54
6029 1 4 11.2 63.9 0.48
6072 1 3 11.1 68.6 0.55
6078 1 1 14.3 67.6 0.43
6079 1 2 13.4 63.5 0.44
6095 1 6 14.9 61.1 0.49
6138 1 3 17.0 61.5 0.72
6162 1 6 15.5 62.4 0.48
2680 2 2 19.4 72.1 --
2682 2 3 14.6 71.6 0.44
2760 2 3 18.1 74.3 0.48
2824 2 6 15.5 63.8 0.58
2931 2 5 13.9 68.7 0.53
2986 2 5 16.4 65.2 0.43
3136 2 5 13.8 68.1 0.65
3165 2 4 14.8 67.2 0.56
3319 2 3 16.7 66.2 0.54
3338 2 4 18.3 66.2 0.57
3340 2 3 19.3 65.9 0.68
3344 2 1 14.0 67.2 0.63
3444 2 1 11.3 71.5 --
3445 2 6 14.0 72.5 0.83
3448 2 1 18.4 65.9 0.38
3532 2 1 20.8 60.4 0.44
3560 2 2 15.2 70.0 0.68
3588 2 5 16.3 71.0 0.61











Table A-2. Continued
PUN, Glucose, Insulin,
Cow Period Diet mg/dl mg/dl ng/ml
3621 2 5 13.6 66.7 0.61
3622 2 6 19.2 65.0 0.52
3633 2 6 15.3 67.7 0.56
3661 2 6 15.8 75.4 0.59
3668 2 1 16.8 71.1 0.41
3703 2 2 15.7 71.0 0.37
3708 2 4 14.7 62.7 0.41
3738 2 5 18.7 68.3 0.43
3755 2 4 14.2 64.8 0.40
3801 2 6 13.7 70.8 0.43
5882 2 2 10.6 63.5 0.51
5896 2 5 12.8 66.6 0.40
6000 2 4 13.5 68.1 0.47
6029 2 3 15.4 66.9 0.40
6072 2 4 14.2 66.0 0.57
6078 2 2 19.9 62.7 0.34
6079 2 3 15.1 65.4 0.36
6095 2 2 14.0 65.2 0.30
6138 2 3 16.6 65.9 0.44
6162 2 1 15.4 62.6 0.26
2680 3 3 13.1 63.0 0.42
2682 3 6 7.9 75.8 0.40
2760 3 2 9.4 73.1 0.34
2824 3 3 10.9 58.1 0.28
2931 3 6 7.8 61.7 0.47
2986 3 4 11.0 59.2 0.29
3136 3 3 12.4 61.6 0.28
3165 3 2 12.0 64.3 0.24
3319 3 1 16.9 61.6 0.26
3338 3 4 13.7 59.3 0.42
3340 3 3 17.1 63.6 0.37
3344 3 5 12.9 69.3 0.33
3444 3 2 -- -- --
3445 3 2 -- --
3448 3 6 11.4 59.3 --
3532 3 1 18.9 60.6 0.37
3560 3 2 10.0 73.0 0.75
3588 3 1 15.3 67.8 0.65
3621 3 5 12.2 68.5 0.70
3622 3 4 19.1 56.7 0.38
3633 3 5 15.3 69.4 --
3661 3 6 10.4 72.3 0.57
3668 3 3 15.6 65.1 0.66
3703 3 4 12.1 61.8 0.47
3708 3 6 8.9 61.7 --
3738 3 2 15.7 60.3 0.69







70



Table A-2. Continued
PUN, Glucose, Insulin,
Cow Period Diet mg/dl mg/dl ng/ml
3755 3 1 17.6 62.0 0.49
3801 3 1 13.3 66.4 0.76
5882 3 1 12.1 61.8 0.66
5896 3 2 15.0 64.9 0.63
6000 3 3 12.0 67.1 0.53
6029 3 4 12.5 61.5 0.69
6072 3 1 12.5 70.5 0.72
6079 3 6 10.4 63.9 0.64
6095 3 6 11.7 64.4 0.42
6138 3 5 14.6 63.0 0.63
6162 3 4 12.3 59.3 0.50















APPENDIX B
RUMINAL PH AND VOLATILE FATTY ACIDS















Table B-1. Volatile fatty acids (VFA) and rumen pH by cow, period, hour of sampling, and diet. Diet 1 = ST-RUP, 2


3 = SF-RUP, 4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP
Iso- Methyl- Iso- Total
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate VFA pH
-------------------------------- ----------------M--------- -------
2682 1 0 2 98.50 27.90 0.68 12.90 1.95 0.42 0.67 143.02 5.96
2682 1 1 2 99.82 28.73 0.66 12.28 1.97 0.44 0.64 144.55 5.92
2682 1 2 2 84.60 25.22 0.59 10.47 1.88 0.37 0.67 123.79 5.81
2682 1 3 2 85.76 24.97 0.40 9.07 1.76 0.31 0.59 122.86 6.12
2682 1 4 2 82.11 24.02 0.40 9.19 1.65 0.33 0.62 118.32 5.98
2682 1 5 2 82.99 25.98 0.49 9.47 1.79 0.34 0.64 121.70 5.86
2682 1 6 2 80.19 23.55 0.61 10.74 2.05 0.42 0.92 118.47 6.07
2682 1 7 2 78.17 24.83 0.58 10.93 2.02 0.39 0.83 117.75 5.98
2682 1 8 2 73.23 22.25 0.54 9.76 1.77 0.34 1.01 108.90 6.04
2682 1 9 2 77.88 23.27 0.55 10.60 1.91 0.37 1.42 116.01 5.92
2682 1 10 2 77.12 23.91 0.54 10.54 1.88 0.35 1.46 115.81 6.11
2682 1 11 2 78.17 24.54 0.53 10.90 1.86 0.37 2.38 118.74 5.99
2682 1 12 2 80.72 24.60 0.52 10.92 1.87 0.38 2.44 121.44 5.90
2682 2 0 5 76.02 16.90 0.76 9.97 2.05 0.57 2.27 108.56 5.79
2682 2 1 5 81.59 20.48 0.88 10.41 2.22 0.57 1.51 117.67 5.53
2682 2 2 5 103.01 29.04 1.14 14.53 2.90 0.73 3.05 154.40 5.54
2682 2 3 5 97.91 26.51 0.99 12.88 2.92 0.69 2.85 144.74 5.63
2682 2 4 5 89.36 23.46 0.88 12.12 2.63 0.59 2.55 131.57 5.65
2682 2 5 5 75.20 19.78 0.53 10.31 2.22 0.43 3.04 111.50 5.61


ST+RUP,













Table B-1. Continued
Iso- Methyl- Iso- Total
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate VFA pH
-------------------------------- ---------------mM-------------------
2682 2 6 5 76.35 21.86 0.58 11.26 2.32 0.42 3.24 116.02 5.74
2682 2 7 5 78.99 22.35 0.70 11.08 2.43 0.42 2.52 118.49 5.73
2682 2 8 5 68.39 18.89 0.40 10.16 2.00 0.33 3.10 103.26 5.61
2682 2 9 5 73.27 19.53 0.48 10.42 2.02 0.36 3.24 109.32 5.70
2682 2 10 5 88.10 24.92 0.65 13.20 2.44 0.42 4.01 133.75 5.63
2682 2 11 5 90.69 25.65 0.61 13.64 2.58 0.46 4.08 137.70 5.85
2682 2 12 5 78.58 21.12 0.61 12.14 2.39 0.50 3.23 118.57 6.26
2682 3 0 3 77.48 16.99 0.51 10.98 1.52 0.45 2.42 110.36 6.49
2682 3 1 3 85.00 22.67 0.72 13.86 1.88 0.55 3.09 127.77 6.23
2682 3 2 3 76.01 27.54 1.20 16.97 2.36 0.64 4.33 129.04 6.35
2682 3 3 3 87.24 31.26 0.79 16.21 1.94 0.46 3.54 141.44 6.03
2682 3 4 3 87.79 27.52 0.68 16.30 2.08 0.46 4.25 139.08 6.15
2682 3 5 3 81.74 26.30 0.62 16.29 1.98 0.39 4.22 131.55 6.28
2682 3 6 3 78.75 24.42 0.51 14.72 1.77 0.29 3.55 124.01 6.29
2682 3 7 3 72.74 22.81 0.28 13.45 1.52 0.28 3.41 114.48 6.40
2682 3 8 3 68.57 21.43 0.24 13.32 1.32 0.25 3.20 108.33 6.40
2682 3 9 3 67.12 19.30 0.38 12.45 1.33 0.25 2.89 103.72 6.37
2682 3 10 3 77.86 20.79 0.35 13.81 1.50 0.28 3.17 117.75 6.32
2682 3 11 3 74.90 19.02 0.38 13.03 1.54 0.30 2.89 112.06 6.41
2682 3 12 3 70.45 17.18 0.38 11.91 1.50 0.29 2.64 104.35 6.38
2824 1 0 4 69.99 20.58 0.20 11.63 1.39 0.09 2.51 106.40 6.84
2824 1 1 4 77.62 22.51 0.26 12.08 1.30 0.13 2.27 116.17 6.40
2824 1 2 4 78.44 25.05 0.32 14.03 1.48 0.26 2.69 122.27 6.22
2824 1 3 4 78.45 25.13 0.38 14.66 1.54 0.30 2.86 123.33 6.29
2824 1 4 4 75.57 24.70 0.31 14.60 1.58 0.32 2.89 119.97 6.31
2824 1 5 4 94.21 30.57 0.39 18.75 1.97 0.35 3.36 149.60 6.19
2824 1 6 4 87.14 29.12 0.40 17.53 1.86 0.30 3.65 140.00 6.04













Table B-1. Continued
Iso- Methyl- Iso- Total
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate VFA pH
-------------------------------- ---------------mM-------------------
2824 1 7 4 84.27 27.23 0.30 16.20 1.88 0.30 3.49 133.67 6.32
2824 1 8 4 92.51 30.28 0.36 18.00 2.18 0.35 4.11 147.79 6.37
2824 1 9 4 78.94 25.81 0.37 14.95 1.86 0.29 3.64 125.86 6.37
2824 1 10 4 75.42 24.28 0.32 13.71 1.64 0.31 3.23 118.91 6.18
2824 1 11 4 77.02 24.69 0.28 14.15 1.81 0.30 3.57 121.82 6.25
2824 1 12 4 70.99 23.32 0.29 12.67 1.64 0.27 2.90 112.07 6.30
2824 2 0 1 81.04 24.45 0.28 12.81 1.37 0.22 3.57 123.74 6.10
2824 2 1 1 98.22 30.14 0.38 15.82 1.44 0.23 3.87 150.11 6.06
2824 2 2 1 97.17 33.23 0.39 17.45 1.75 0.25 4.18 154.42 6.03
2824 2 3 1 86.66 28.04 0.39 14.94 1.66 0.21 3.87 135.77 6.02
2824 2 4 1 85.80 29.16 0.29 15.58 1.58 0.20 4.18 136.80 5.95
2824 2 5 1 79.88 26.21 0.31 13.77 1.34 0.16 3.55 125.22 5.78
2824 2 6 1 77.03 27.52 0.31 14.63 1.48 0.16 4.01 125.13 5.89
2824 2 7 1 79.80 26.70 0.33 13.36 1.28 0.16 3.38 125.03 5.83
2824 2 8 1 80.55 29.09 0.38 15.89 1.67 0.19 4.34 132.11 5.76
2824 2 9 1 79.49 29.68 0.30 15.86 1.54 0.19 4.34 131.40 5.79
2824 2 10 1 79.68 29.97 0.32 15.93 1.55 0.18 4.36 132.00 5.81
2824 2 11 1 78.04 27.38 0.25 13.76 1.40 0.17 3.70 124.70 5.78
2824 2 12 1 75.01 25.26 0.20 12.85 1.32 0.14 3.57 118.35 5.80
2824 3 0 6 82.35 25.36 0.54 12.22 1.50 0.38 3.31 125.66 6.09
2824 3 1 6 84.17 27.66 0.68 13.92 1.73 0.44 3.88 132.48 6.01
2824 3 2 6 78.20 29.21 0.78 14.80 1.96 0.49 4.35 129.80 6.00
2824 3 3 6 93.30 32.40 0.80 15.46 2.05 0.53 4.41 148.95 6.04
2824 3 4 6 89.34 30.59 0.74 14.45 1.99 0.51 4.25 141.87 6.22
2824 3 5 6 88.67 30.24 0.80 15.44 2.12 0.59 4.48 142.33 6.28
2824 3 6 6 80.07 27.88 0.83 14.37 1.89 0.45 4.09 129.57 6.52
2824 3 7 6 80.30 26.49 0.63 13.24 1.67 0.41 3.81 126.54 6.15















Table B-1. Continued
Iso- Methyl- Iso- Total
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate VFA pH
------------------------------- ---------------mM-------------------
2824 3 8 6 86.44 27.66 0.59 13.52 1.70 0.42 3.85 134.18 6.05
2824 3 9 6 93.88 29.77 0.68 15.13 1.73 0.42 4.01 145.63 6.08
2824 3 10 6 87.18 30.28 0.70 13.21 1.62 0.43 3.87 137.28 6.19
2824 3 11 6 86.75 29.87 0.66 14.25 1.64 0.41 3.97 137.56 6.03
2824 3 12 6 96.10 32.76 0.68 16.65 1.86 0.50 4.62 153.16 6.10
3755 1 0 3 76.65 20.46 0.68 11.37 1.63 0.30 2.39 113.48 6.26
3755 1 1 3 86.10 26.73 0.69 13.81 1.70 0.30 2.85 132.17 6.30
3755 1 2 3 82.73 26.96 0.74 13.98 2.25 0.43 4.14 131.22 6.00
3755 1 3 3 88.83 29.53 0.76 16.89 2.45 0.46 4.32 143.24 6.09
3755 1 4 3 89.76 28.79 0.78 15.62 2.57 0.44 4.46 142.42 6.13
3755 1 5 3 85.60 26.85 0.73 13.65 2.30 0.45 3.93 133.51 6.27
3755 1 6 3 81.14 26.12 0.75 14.32 2.42 0.46 3.58 128.78 6.15
3755 1 7 3 79.27 23.87 0.77 12.79 2.39 0.50 3.36 122.97 6.18
3755 1 8 3 78.49 23.20 0.85 12.35 2.28 0.43 3.04 120.64 5.97
3755 1 9 3 81.06 24.17 0.85 13.47 2.40 0.47 3.08 125.49 6.23
3755 1 10 3 75.03 20.22 0.66 10.87 2.09 0.42 2.80 112.09 5.89
3755 1 11 3 74.72 19.62 0.67 10.67 2.29 0.35 2.52 110.85 6.09
3755 1 12 3 72.11 23.36 0.70 12.16 1.95 0.36 2.82 113.45 6.29
3755 2 0 6 71.19 17.27 0.69 11.12 1.85 0.32 2.59 105.03 5.92
3755 2 1 6 86.56 23.04 0.72 14.21 2.18 0.37 2.93 130.01 5.73
3755 2 2 6 77.69 20.21 0.68 12.28 2.32 0.30 2.91 116.39 5.73
3755 2 3 6 85.24 23.62 0.70 14.08 2.37 0.36 3.34 129.71 5.74
3755 2 4 6 94.70 25.90 0.81 16.07 2.93 0.36 4.05 144.82 5.76
3755 2 5 6 76.90 20.97 0.65 13.00 2.25 0.29 3.31 117.38 5.98
3755 2 6 6 73.55 19.47 0.54 12.15 2.44 0.28 3.33 111.75 5.75
3755 2 7 6 79.19 21.70 0.64 13.75 2.41 0.27 3.38 121.34 5.72
3755 2 8 6 69.55 19.09 0.55 11.87 1.97 0.26 3.34 106.63 5.62















Table B-1. Continued
Iso- Methyl- Iso- Total
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate VFA pH
------------------------------- ---------------mM-------------------
3755 2 9 6 66.81 17.11 0.50 10.31 1.60 0.26 3.14 99.73 6.04
3755 2 10 6 69.61 19.91 0.51 12.40 1.61 0.25 3.10 107.38 5.86
3755 2 11 6 78.92 24.33 0.53 14.66 2.09 0.23 3.13 123.88 5.81
3755 2 12 6 72.25 21.79 0.49 12.82 2.08 0.27 3.36 113.05 6.01
3755 3 0 4 85.40 22.44 0.78 10.37 1.76 0.39 2.32 123.46 6.29
3755 3 1 4 83.73 25.21 0.73 11.43 2.07 0.44 2.80 126.40 6.16
3755 3 2 4 91.51 31.22 0.87 14.97 2.15 0.53 4.27 145.51 6.19
3755 3 3 4 95.12 30.84 0.82 14.34 2.09 0.49 3.88 147.58 6.18
3755 3 4 4 99.97 31.32 0.96 14.87 2.55 0.67 4.01 154.34 6.05
3755 3 5 4 79.01 29.31 0.95 13.54 2.64 0.52 3.46 129.42 6.16
3755 3 6 4 81.27 27.42 0.95 13.54 3.17 0.59 3.35 130.28 6.07
3755 3 7 4 85.04 28.35 0.90 13.39 2.46 0.52 3.02 133.67 6.19
3755 3 8 4 85.71 29.32 1.00 13.81 2.83 0.65 3.58 136.90 6.17
3755 3 9 4 78.26 24.19 0.86 11.48 2.18 0.51 2.65 120.13 6.17
3755 3 10 4 83.81 27.82 0.97 13.33 2.53 0.56 3.13 132.14 5.98
3755 3 11 4 67.99 22.20 0.82 10.51 1.90 0.39 2.50 106.29 5.91
3755 3 12 4 82.49 26.96 0.89 12.85 2.19 0.45 3.21 129.03 5.91
5896 1 0 5 69.23 22.00 0.67 8.37 0.88 0.22 1.01 102.38 6.17
5896 1 1 5 78.42 25.01 0.94 11.01 1.30 0.35 2.27 119.30 6.04
5896 1 2 5 99.09 32.08 1.80 14.86 1.82 0.56 3.79 153.99 5.95
5896 1 3 5 87.32 25.81 0.87 13.01 1.42 0.36 2.43 131.22 5.99
5896 1 4 5 77.63 24.41 0.83 11.62 1.19 0.32 2.97 118.97 5.81
5896 1 5 5 78.41 24.37 0.76 12.34 1.10 0.29 3.12 120.37 5.94
5896 1 6 5 92.28 30.01 0.97 15.45 1.54 0.40 4.23 144.88 5.67
5896 1 7 5 85.07 29.41 0.82 14.59 1.25 0.33 4.32 135.80 6.04
5896 1 8 5 79.40 22.27 0.68 12.96 1.25 0.30 3.15 120.02 5.79
5896 1 9 5 78.97 22.39 0.73 12.43 1.40 0.33 3.00 119.25 6.14















Table B-1. Continued
Iso- Methyl- Iso- Total
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate VFA pH
------------------------------- ---------------mM-------------------
5896 1 10 5 88.29 26.87 0.85 14.38 1.64 0.58 3.91 136.51 5.79
5896 1 11 5 81.88 23.62 0.73 12.16 1.31 0.49 3.03 123.22 5.90
5896 1 12 5 81.58 23.32 0.76 11.98 1.37 0.37 2.66 122.04 5.94
5896 2 0 2 75.16 21.10 0.59 12.51 1.07 0.28 2.54 113.25 6.13
5896 2 1 2 87.28 28.26 0.68 15.76 1.44 0.32 3.52 137.26 6.06
5896 2 2 2 86.99 29.02 0.79 16.64 1.52 0.33 3.59 138.87 5.99
5896 2 3 2 92.98 31.50 0.84 17.55 1.80 0.36 4.16 149.21 6.04
5896 2 4 2 91.21 31.95 0.82 18.61 1.88 0.33 4.09 148.88 5.98
5896 2 5 2 96.81 32.20 0.87 18.74 1.90 0.35 4.45 155.31 6.23
5896 2 6 2 80.65 31.68 0.88 19.57 1.72 0.38 4.94 139.82 6.09
5896 2 7 2 74.84 25.65 0.64 14.53 1.28 0.28 3.26 120.49 6.14
5896 2 8 2 87.69 31.39 0.83 19.54 1.81 0.37 4.51 146.14 6.11
5896 2 9 2 78.38 26.96 0.69 13.81 1.53 0.34 3.76 125.47 5.99
5896 2 10 2 78.65 34.04 0.84 17.90 1.71 0.35 4.53 138.01 6.01
5896 2 11 2 93.43 35.17 0.79 19.78 1.71 0.33 4.69 155.91 5.95
5896 2 12 2 79.93 29.85 0.67 16.91 1.31 0.31 4.80 133.77 5.99
5896 3 0 1 83.42 20.94 0.72 10.26 1.26 0.40 2.79 119.80 6.27
5896 3 1 1 83.96 22.84 0.93 10.58 1.63 0.36 2.33 122.62 6.22
5896 3 2 1 90.75 23.56 0.84 10.93 1.52 0.38 2.28 130.26 6.22
5896 3 3 1 88.90 23.15 0.86 10.66 1.55 0.37 2.64 128.14 6.23
5896 3 4 1 91.89 23.78 0.82 11.45 1.63 0.49 2.58 132.64 6.08
5896 3 5 1 89.27 23.08 0.76 10.95 1.83 0.36 2.35 128.59 6.28
5896 3 6 1 85.83 25.11 0.89 12.16 2.87 0.56 2.91 130.32 5.94
5896 3 7 1 75.47 21.56 0.75 9.79 2.81 0.50 2.29 113.17 6.07
5896 3 8 1 69.67 19.57 0.64 8.77 1.91 0.36 2.02 102.94 6.11
5896 3 9 1 77.53 21.83 0.63 9.39 1.61 0.33 2.22 113.53 6.30
5896 3 10 1 79.76 23.27 0.68 10.23 1.54 0.36 2.32 118.16 6.12















Table B-1. Continued
Iso- Methyl- Iso- Total
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate VFA pH
------------------------------- ---------------mM-------------------
5896 3 11 1 85.21 27.37 0.79 12.22 1.55 0.34 2.64 130.12 5.98
5896 3 12 1 86.38 26.58 0.82 11.81 1.53 0.31 2.71 130.13 6.06
6078 1 0 6 72.24 22.29 0.68 10.05 1.91 0.41 2.15 109.74 6.26
6078 1 1 6 84.18 26.80 0.91 13.01 2.57 0.53 2.67 130.65 6.15
6078 1 2 6 83.15 25.92 0.92 15.12 3.09 0.59 3.11 131.88 6.04
6078 1 3 6 79.48 26.20 0.84 12.75 2.93 0.48 2.81 125.48 6.16
6078 1 4 6 78.21 24.66 0.81 11.93 2.58 0.43 2.70 121.32 5.90
6078 1 5 6 86.06 28.59 0.83 14.14 3.05 0.49 3.05 136.21 5.92
6078 1 6 6 84.08 28.27 0.83 13.50 2.62 0.45 2.84 132.59 6.03
6078 1 7 6 86.95 29.39 0.88 14.98 3.02 0.47 3.00 138.69 6.06
6078 1 8 6 94.81 32.23 1.04 16.03 3.23 1.27 3.26 151.87 5.73
6078 1 9 6 92.19 30.90 0.91 15.21 2.98 1.24 3.30 146.74 6.07
6078 1 10 6 75.38 27.41 0.83 12.16 2.44 1.02 2.61 121.85 6.04
6078 1 11 6 79.07 29.98 0.96 13.92 2.74 0.43 2.97 130.07 6.26
6078 1 12 6 85.88 32.49 0.98 15.55 3.04 0.47 3.11 141.52 6.28
6078 2 0 3 70.54 23.45 0.89 10.74 2.06 0.44 2.09 110.22 5.85
6078 2 1 3 89.09 27.22 1.10 13.62 2.93 0.54 3.04 137.54 5.93
6078 2 2 3 90.83 30.78 1.35 15.63 3.89 0.61 3.44 146.52 5.77
6078 2 3 3 88.61 26.99 1.06 12.82 3.63 0.53 3.11 136.75 5.69
6078 2 4 3 94.46 28.89 1.12 14.56 4.29 0.75 3.42 147.49 5.69
6078 2 5 3 74.16 20.70 1.13 9.57 3.55 0.36 1.97 111.45 5.71
6078 2 6 3 82.87 25.16 1.05 12.80 3.45 0.56 2.94 128.83 5.67
6078 2 7 3 76.64 22.56 0.85 11.80 2.99 0.48 2.42 117.74 5.76
6078 2 8 3 79.06 26.06 0.91 12.82 3.10 0.46 2.74 125.15 5.78
6078 2 9 3 76.13 25.61 0.87 12.38 3.35 0.44 2.78 121.56 5.81
6078 2 10 3 72.38 22.93 0.90 11.35 2.96 0.37 2.80 113.68 5.77
6078 2 11 3 75.49 25.56 0.87 12.10 3.12 0.35 2.68 120.17 5.65















Table B-1. Continued
Iso- Methyl- Iso- Total
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate VFA pH
------------------------------- ---------------mM-------------------
6078 2 12 3 67.82 21.68 0.69 10.14 2.57 0.33 2.11 105.34 5.52
6162 1 0 1 71.60 21.03 0.53 12.18 0.89 0.12 2.87 109.22 5.95
6162 1 1 1 79.68 26.59 0.65 14.65 1.00 0.21 2.83 125.61 6.09
6162 1 2 1 81.85 27.08 0.63 16.12 1.28 0.30 3.81 131.05 5.74
6162 1 3 1 89.28 26.91 0.86 13.21 1.75 0.38 2.96 135.36 5.95
6162 1 4 1 86.09 27.38 0.59 17.05 1.60 0.31 4.23 137.24 5.80
6162 1 5 1 77.14 25.63 0.57 15.86 1.54 0.30 3.90 124.94 5.92
6162 1 6 1 64.03 21.12 0.54 12.19 1.28 0.30 2.92 102.39 6.17
6162 1 7 1 64.82 21.87 0.53 13.55 1.22 0.28 3.24 105.51 6.22
6162 1 8 1 72.25 26.03 0.58 15.46 1.23 0.31 3.36 119.22 6.07
6162 1 9 1 60.59 21.48 0.56 12.64 1.09 0.25 2.89 99.50 6.44
6162 1 10 1 71.99 23.38 0.50 13.83 1.29 0.26 3.44 114.68 6.13
6162 1 11 1 71.36 28.68 0.64 16.43 1.36 0.28 3.62 122.37 5.98
6162 1 12 1 70.95 23.86 0.59 12.14 1.21 0.28 2.90 111.94 5.80
6162 2 0 2 59.08 21.45 0.69 9.26 1.62 0.46 2.52 95.07 6.03
6162 2 1 2 79.76 28.58 0.81 10.39 1.94 0.64 3.09 125.21 6.08
6162 2 2 2 78.27 28.07 0.88 11.04 2.17 0.63 3.30 124.36 6.06
6162 2 3 2 76.56 28.30 0.82 11.21 2.23 0.61 3.77 123.49 6.07
6162 2 4 2 78.51 28.29 0.81 11.05 2.27 0.56 3.68 125.18 5.93
6162 2 5 2 70.99 24.63 0.80 9.54 1.72 0.36 2.82 110.87 5.99
6162 2 6 2 72.22 23.01 0.82 9.13 1.80 0.38 3.04 110.39 5.79
6162 2 7 2 71.51 26.99 0.87 10.18 2.00 0.41 3.21 115.17 6.12
6162 2 8 2 66.99 25.51 0.78 9.57 1.97 0.44 3.16 108.43 6.02
6162 2 9 2 69.24 27.52 0.77 10.33 2.09 0.46 3.53 113.94 6.25
6162 2 10 2 78.73 30.50 0.88 11.92 2.26 0.54 3.92 128.75 5.92
6162 2 11 2 75.51 30.32 0.95 11.82 2.28 0.49 3.64 125.00 5.87
6162 2 12 2 65.41 24.81 0.77 9.48 1.86 0.47 3.02 105.83 5.73















Table B-1. Continued
Iso- Methyl- Iso-
Cow Period Hour Diet Acetate Propionate Butyrate Butyrate Butyrate Valerate Valerate


Total
VFA


------------------------------------m----


4 70.45
4 88.06
4 84.53
4 77.95
4 71.51
4 86.13
4 85.87
4 95.54
4 80.76
4 89.12
4 96.85
4 80.24
4 67.19


20.79
27.52
28.18
23.02
21.82
29.18
27.55
29.86
27.93
28.13
30.33
27.09
22.98


0.80
1.12
1.09
0.84
0.69
1.01
0.82
0.86
0.76
0.79
0.88
0.72
0.64


10.58
13.23
14.47
11.93
12.13
16.76
14.73
16.45
14.16
15.33
16.69
13.99
11.43


1.76
1.83
1.84
1.82
1.62
2.22
1.77
2.17
1.60
1.59
1.83
1.58
1.28


0.36
0.39
0.41
0.37
0.26
0.38
0.31
0.35
0.32
0.29
0.31
0.30
0.23


2.69 107.44
3.11 135.26
3.57 134.09
3.34 119.26
3.29 111.31
4.19 139.87
2.63 133.68
4.26 149.49
3.62 129.15
3.71 138.97
4.04 150.93
2.81 126.72
2.55 106.30


6162
6162
6162
6162
6162
6162
6162
6162
6162
6162
6162
6162
6162


pH

6.21
6.13
6.04
6.00
5.84
5.79
5.71
5.93
5.87
6.07
5.86
5.83
6.06

















APPENDIX C
IN SITU DEGRADATION OF SORGHUM SILAGE

Table C-1. In situ degradation of sorghum silage by cow, period, diet, and
hour of sampling. Diet 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP,
4 = SF+RUP, 5 = SU-RUP, and 6 = SU+RUP.
Original Remaining Remaining
Cow Period Diet Hour DM, g DM, g NDF, g
2682 1 2 0 4.54 3.50 3.16
2682 1 2 0 4.54 3.52 3.14
2682 1 2 0 4.53 3.52 3.21
2682 1 2 6 4.53 3.24 2.88
2682 1 2 6 4.54 3.26 2.90
2682 1 2 12 4.54 2.99 2.67
2682 1 2 12 4.54 3.00 2.69
2682 1 2 18 4.53 2.79 2.52
2682 1 2 18 4.54 2.71 2.43
2682 1 2 24 4.53 2.57 2.30
2682 1 2 24 4.54 2.61 2.30
2682 1 2 30 4.53 2.31 2.04
2682 1 2 30 4.54 2.27 2.02
2682 1 2 48 4.54 2.02 1.81
2682 1 2 48 4.54 1.99 1.75
2682 2 3 0 4.54 3.47 2.93
2682 2 3 0 4.54 3.47 2.94
2682 2 3 0 4.54 -- --
2682 2 3 6 4.54 3.24 2.87
2682 2 3 6 4.54 3.23 2.87
2682 2 3 12 4.54 2.94 2.63
2682 2 3 12 4.54
2682 2 3 18 4.54 2.62 2.35
2682 2 3 18 4.54 2.67 2.36
2682 2 3 24 4.54 2.68 2.40
2682 2 3 24 4.54 2.85 2.53
2682 2 3 30 4.54 2.30 2.03
2682 2 3 30 4.54 2.49 2.22
2682 2 3 48 4.54 2.14 1.89
2682 2 3 48 4.54 2.05 1.80
2682 3 6 0 4.54 3.39 2.95
2682 3 6 0 4.54 3.38 2.91
2682 3 6 0 4.54 3.40 2.95
2682 3 6 6 4.54 3.21 2.85
2682 3 6 6 4.54 3.15 2.81
2682 3 6 12 4.54 3.05 2.72







82



Table C-1. Continued
Original Remaining Remaining
Cow Period Diet Hour DM, g DM, g NDF, g
2682 3 6 12 4.54 3.06 2.72
2682 3 6 18 4.54 2.97 2.64
2682 3 6 18 4.54 2.91 2.61
2682 3 6 24 4.54 2.73 2.46
2682 3 6 24 4.54 2.84 2.55
2682 3 6 30 4.54 2.56 2.31
2682 3 6 30 4.54 2.63 2.37
2682 3 6 48 4.54 2.15 1.90
2682 3 6 48 4.54 2.32 2.06
2824 1 5 0 4.54 3.50 3.16
2824 1 5 0 4.54 3.52 3.14
2824 1 5 0 4.53 3.52 3.21
2824 1 5 6 4.54 3.28 2.94
2824 1 5 6 4.54 3.29 2.94
2824 1 5 12 4.54 3.02 2.74
2824 1 5 12 4.54 3.13 2.80
2824 1 5 18 4.54 2.95 2.68
2824 1 5 18 4.54 2.98 2.70
2824 1 5 24 4.54 2.85 2.58
2824 1 5 24 4.54 2.83 2.54
2824 1 5 30 4.54 2.71 2.44
2824 1 5 30 4.54 2.58 2.34
2824 1 5 48 4.54 2.11 1.83
2824 1 5 48 4.54 2.22 1.91
2824 2 6 0 4.54 3.47 2.93
2824 2 6 0 4.54 3.47 2.94
2824 2 6 0 4.54 -- --
2824 2 6 6 4.54 3.20 2.85
2824 2 6 6 4.54
2824 2 6 12 4.54 2.89 2.58
2824 2 6 12 4.53 2.95 2.66
2824 2 6 18 4.54 2.88 2.61
2824 2 6 18 4.54 2.88 2.61
2824 2 6 24 4.54 2.60 2.32
2824 2 6 24 4.54
2824 2 6 30 4.54 2.47 2.23
2824 2 6 30 4.54 2.44 2.16
2824 2 6 48 4.54 2.16 1.93
2824 2 6 48 4.54 2.20 1.95
2824 3 3 0 4.54 3.39 2.95
2824 3 3 0 4.54 3.38 2.91
2824 3 3 0 4.54 3.40 2.95
2824 3 3 6 4.54 3.26 2.89
2824 3 3 6 4.54 3.21 2.88
2824 3 3 12 4.54 3.08 2.76
2824 3 3 12 4.54 3.04 2.71







83



Table C-1. Continued
Original Remaining Remaining
Cow Period Diet Hour DM, g DM, g NDF, g
2824 3 3 18 4.54 2.79 2.50
2824 3 3 18 4.54 2.77 2.47
2824 3 3 24 4.54 2.86 2.56
2824 3 3 24 4.54 2.83 2.52
2824 3 3 30 4.54 2.42 2.17
2824 3 3 30 4.54 2.39 2.11
2824 3 3 48 4.54 2.08 1.83
2824 3 3 48 4.54 2.04 1.79
3755 1 3 0 4.54 3.50 3.16
3755 1 3 0 4.54 3.52 3.14
3755 1 3 0 4.53 3.52 3.21
3755 1 3 6 4.54 3.14 2.81
3755 1 3 6 4.54 3.24 2.83
3755 1 3 12 4.54 3.02 2.69
3755 1 3 12 4.54 2.99 2.66
3755 1 3 18 4.53 2.76 2.47
3755 1 3 18 4.54 2.78 2.47
3755 1 3 24 4.54 2.42 2.16
3755 1 3 24 4.54 2.47 2.18
3755 1 3 30 4.54 2.20 1.92
3755 1 3 30 4.54 2.16 1.89
3755 1 3 48 4.54 1.82 1.57
3755 1 3 48 4.54 1.87 1.62
3755 2 4 0 4.54 3.47 2.93
3755 2 4 0 4.54 3.47 2.94
3755 2 4 0 4.54 -- --
3755 2 4 6 4.54 3.20 2.84
3755 2 4 6 4.54 3.25 2.88
3755 2 4 12 4.54 2.91 2.60
3755 2 4 12 4.54 2.88 2.59
3755 2 4 18 4.53 2.73 2.47
3755 2 4 18 4.54 2.81 2.54
3755 2 4 24 4.54 2.65 2.38
3755 2 4 24 4.54 2.52 2.29
3755 2 4 30 4.54 2.29 2.07
3755 2 4 30 4.54 2.49 2.24
3755 2 4 48 4.54 1.93 1.68
3755 2 4 48 4.54 2.12 1.85
3755 3 1 0 4.54 3.39 2.95
3755 3 1 0 4.54 3.38 2.91
3755 3 1 0 4.54 3.40 2.95
3755 3 1 6 4.54 3.28 2.89
3755 3 1 6 4.54 3.23 2.84
3755 3 1 12 4.54 3.00 2.66
3755 3 1 12 4.54 3.05 2.74
3755 3 1 18 4.54 2.84 2.54







84



Table C-1. Continued
Original Remaining Remaining
Cow Period Diet Hour DM, g DM, g NDF, g
3755 3 1 18 4.54 2.84 2.55
3755 3 1 24 4.54 2.64 2.38
3755 3 1 24 4.54 2.60 2.36
3755 3 1 30 4.54 2.39 2.15
3755 3 1 30 4.54 2.51 2.27
3755 3 1 48 4.54 2.02 1.79
3755 3 1 48 4.54 1.93 1.71
5896 1 4 0 4.54 3.50 3.16
5896 1 4 0 4.54 3.52 3.14
5896 1 4 0 4.53 3.52 3.21
5896 1 4 6 4.54 3.20 2.86
5896 1 4 6 4.54 3.13 2.79
5896 1 4 12 4.54 2.89 2.61
5896 1 4 12 4.54 2.99 2.69
5896 1 4 18 4.54 2.64 2.36
5896 1 4 18 4.54 2.63 2.32
5896 1 4 24 4.53 2.46 2.21
5896 1 4 24 4.53 2.41 2.17
5896 1 4 30 4.54 2.40 2.12
5896 1 4 30 4.54 2.16 1.92
5896 1 4 48 4.54 1.81 1.61
5896 1 4 48 4.54 1.88 1.59
5896 2 5 0 4.54 3.47 2.93
5896 2 5 0 4.54 3.47 2.94
5896 2 5 0 4.54 -- --
5896 2 5 6 4.54 3.09 2.73
5896 2 5 6 4.54 3.12 2.77
5896 2 5 12 4.53 2.87 2.59
5896 2 5 12 4.54 2.88 2.60
5896 2 5 18 4.53 2.69 2.40
5896 2 5 18 4.54 2.78 2.52
5896 2 5 24 4.54 2.57 2.31
5896 2 5 24 4.53 2.56 2.29
5896 2 5 30 4.54 2.49 2.21
5896 2 5 30 4.54 2.31 2.03
5896 2 5 48 4.54 1.93 1.69
5896 2 5 48 4.54 1.91 1.69
5896 3 2 0 4.54 3.39 2.95
5896 3 2 0 4.54 3.38 2.91
5896 3 2 0 4.54 3.40 2.95
5896 3 2 6 4.54 3.05 2.74
5896 3 2 6 4.54 3.10 2.78
5896 3 2 12 4.54 2.77 2.51
5896 3 2 12 4.54 2.67 2.43
5896 3 2 18 4.54 2.49 2.25
5896 3 2 18 4.54 2.51 2.26











Table C-1. Continued
Original Remaining Remaining
Cow Period Diet Hour DM, g DM, g NDF, g
5896 3 2 24 4.54 2.27 2.03
5896 3 2 24 4.54 2.23 2.00
5896 3 2 30 4.54 2.16 1.95
5896 3 2 30 4.54 2.21 1.98
5896 3 2 48 4.54 1.74 1.53
5896 3 2 48 4.54 1.77 1.56
6078 1 1 0 4.54 3.50 3.16
6078 1 1 0 4.54 3.52 3.14
6078 1 1 0 4.53 3.52 3.21
6078 1 1 6 4.54 3.27 2.88
6078 1 1 6 4.54 3.25 2.90
6078 1 1 12 4.53 3.18 2.85
6078 1 1 12 4.54 3.08 2.75
6078 1 1 18 4.54 2.97 2.68
6078 1 1 18 4.53 3.00 2.72
6078 1 1 24 4.54 2.79 2.50
6078 1 1 24 4.54 2.88 2.57
6078 1 1 30 4.54 2.60 2.34
6078 1 1 30 4.54 2.58 2.30
6078 1 1 48 4.54 2.02 1.78
6078 1 1 48 4.54
6078 2 1 0 4.54 3.47 2.93
6078 2 2 0 4.54 3.47 2.94
6078 2 2 0 4.54 -- --
6078 2 2 6 4.54 3.27 2.87
6078 2 2 6 4.54 3.33 2.94
6078 2 2 12 4.54 3.01 2.69
6078 2 2 12 4.54 2.82 2.51
6078 2 2 18 4.54 2.81 2.52
6078 2 2 18 4.54 2.69 2.41
6078 2 2 24 4.54 2.83 2.51
6078 2 2 24 4.54 2.58 2.30
6078 2 2 30 4.54 2.44 2.17
6078 2 2 30 4.54 2.43 2.16
6078 2 2 48 4.54 2.22 1.97
6078 2 2 48 4.53 2.09 1.85
6162 1 6 0 4.54 3.50 3.16
6162 1 6 0 4.54 3.52 3.14
6162 1 6 0 4.53 3.52 3.21
6162 1 6 6 4.54 3.11 2.73
6162 1 6 6 4.53 3.13 2.74
6162 1 6 12 4.54 2.90 2.60
6162 1 6 12 4.54 2.85 2.56
6162 1 6 18 4.54 2.73 2.44
6162 1 6 18 4.54 2.87 2.56
6162 1 6 24 4.54 2.65 2.37







86



Table C-1. Continued
Original Remaining Remaining
Cow Period Diet Hour DM, g DM, g NDF, g
6162 1 6 24 4.54 2.53 2.24
6162 1 6 30 4.54 2.26 2.02
6162 1 6 30 4.54 2.29 2.04
6162 1 6 48 4.54 2.02 1.75
6162 1 6 48 4.54 1.86 1.66
6162 2 1 0 4.54 3.47 2.93
6162 2 1 0 4.54 3.47 2.94
6162 2 1 0 4.54 -- --
6162 2 1 6 4.54 3.12 2.78
6162 2 1 6 4.54 3.13 2.76
6162 2 1 12 4.54 2.92 2.62
6162 2 1 12 4.54 2.92 2.59
6162 2 1 18 4.54 2.73 2.42
6162 2 1 18 4.54 -- --
6162 2 1 24 4.54 2.63 2.36
6162 2 1 24 4.54 2.63 2.35
6162 2 1 30 4.54 2.37 2.12
6162 2 1 30 4.54 2.28 2.04
6162 2 1 48 4.54 2.16 1.89
6162 2 1 48 4.54 2.16 1.90
6162 3 4 0 4.54 3.39 2.95
6162 3 4 0 4.54 3.38 2.91
6162 3 4 0 4.54 3.40 2.95
6162 3 4 6 4.54 3.19 2.83
6162 3 4 6 4.54 3.15 2.82
6162 3 4 12 4.54 2.94 2.59
6162 3 4 12 4.54 2.94 2.64
6162 3 4 18 4.54 2.85 2.58
6162 3 4 18 4.54 2.77 2.50
6162 3 4 24 4.54 2.65 2.38
6162 3 4 24 4.54 2.55 2.26
6162 3 4 30 4.54 2.51 2.21
6162 3 4 30 4.54 2.39 2.12
6162 3 4 48 4.54 1.98 1.74
6162 3 4 48 4.54 -- --















APPENDIX D
NUTRIENT INTAKES















Table D-1. Offered feed and nutrients by cow, period and diet. Diet 1 = ST-RUP, 2 = ST+RUP, 3 = SF-RUP,


4 = SF+RUP, 5


Period
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1


Diet
3
2
6
5
6
2
3
2
1
6
5
5
2
6
4
3
4
5
1
4


SU-RUP, and 6


Offered,
kg/d
27.2
25.6
33.0
25.4
29.7
28.8
30.1
25.6
27.0
24.8
25.6
29.5
28.8
32.7
28.8
29.3
29.9
28.2
29.7
29.1


DM
0.46
0.45
0.47
0.48
0.46
0.42
0.47
0.45
0.45
0.47
0.48
0.47
0.45
0.47
0.44
0.47
0.48
0.46
0.44
0.46


SU+RUP.
Ash CP NDF Sugar Starch NDSF
-----------------------------------% of DM----------------------------------


0.07
0.07
0.07
0.07
0.07
0.06
0.07
0.06
0.06
0.07
0.07
0.08
0.06
0.07
0.06
0.06
0.06
0.07
0.07
0.06


0.14
0.16
0.17
0.18
0.17
0.16
0.15
0.17
0.16
0.17
0.18
0.17
0.16
0.18
0.16
0.17
0.17
0.16
0.17
0.16


0.40
0.39
0.37
0.37
0.39
0.40
0.41
0.40
0.40
0.40
0.40
0.40
0.40
0.39
0.43
0.38
0.38
0.43
0.39
0.38


0.10
0.05
0.16
0.13
0.16
0.05
0.09
0.05
0.05
0.14
0.14
0.13
0.05
0.14
0.08
0.08
0.08
0.14
0.04
0.08


0.16
0.25
0.14
0.13
0.14
0.25
0.16
0.25
0.25
0.14
0.13
0.15
0.23
0.13
0.16
0.16
0.17
0.15
0.21
0.15


0.06
0.02
0.04
0.06
0.03
0.01
0.05
0.02
0.02

0.03
0.02
0.04
0.05
0.03
0.08
0.08

0.05
0.08


Cow
2680
2682
2760
2824
2931
2986
3136
3165
3319
3338
00 3340
00 3344
3444
3445
3448
3532
3560
3588
3621
3622














Table D-1. Continued
Offered, Ash CP NDF Sugar Starch NDSF
Cow Period Diet kg/d DM --------------------------------% of DM------------------------------
3633 1 3 26.1 0.48 0.06 0.17 0.40 0.08 0.16 0.05
3661 1 2 25.1 0.45 0.07 0.16 0.39 0.04 0.26 --
3668 1 1 24.9 0.44 0.06 0.16 0.38 0.05 0.23 --
3703 1 2 28.2 0.45 0.06 0.15 0.36 0.05 0.22 0.04
3708 1 4 24.1 0.49 0.06 0.16 0.38 0.07 0.17 0.03
3738 1 4 24.3 0.46 0.06 0.17 0.41 0.08 0.15 0.01
3755 1 3 25.0 0.46 0.06 0.17 0.41 0.09 0.12 0.05
3801 1 1 24.5 0.46 0.07 0.17 0.41 0.04 0.23 0.00
5882 1 5 28.2 0.45 0.07 0.18 0.39 0.13 0.13 0.06
5896 1 4 24.7 0.44 0.06 0.16 0.40 0.07 0.16 0.06
6000 1 1 28.7 0.45 0.06 0.17 0.39 0.04 0.24 0.00
6029 1 4 28.7 0.50 0.06 0.16 0.37 0.08 0.18 0.03
6072 1 3 28.6 0.47 0.07 0.16 0.41 0.08 0.17 0.02 oo
6078 1 1 25.7 0.46 0.06 0.18 0.38 0.05 0.24 --
6079 1 2 27.9 0.42 0.06 0.18 0.39 0.04 0.25 0.00
6095 1 6 32.3 0.44 0.07 0.18 0.40 0.14 0.14 0.04
6138 1 3 26.3 0.42 0.07 0.17 0.40 0.07 0.18 0.05
6162 1 6 32.5 0.48 0.07 0.16 0.39 0.14 0.09 0.11
2680 2 2 30.6 0.47 0.07 0.16 0.39 0.04 0.23 0.04
2682 2 3 25.9 0.47 0.07 0.17 0.40 0.08 0.16 0.05
2760 2 3 32.8 0.45 0.07 0.18 0.39 0.08 0.15 0.07
2824 2 6 26.5 0.47 0.07 0.17 0.39 0.14 0.13 0.03
2931 2 5 35.2 0.50 0.07 0.17 0.35 0.13 0.14 0.06
2986 2 5 34.0 0.47 0.07 0.18 0.38 0.13 0.13 0.06
3136 2 5 31.1 0.47 0.07 0.18 0.39 0.13 0.13 0.07
3165 2 4 29.6 0.46 0.07 0.17 0.40 0.08 0.13 0.07
3319 2 3 28.5 0.46 0.07 0.17 0.40 0.07 0.16 0.07
3338 2 4 29.7 0.47 0.07 0.17 0.41 0.07 0.13 0.07
3340 2 3 25.4 0.44 0.07 0.17 0.41 0.06 0.15 0.06