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1 EFFECT OF SUPPLEMENTING BAHIAGRASS HAY WITH WARM SEASON LEGUME HAYS ON FEED INTAKE, DIGESTIBILITY, NITROGEN RETENTION, BODY WEIGHT GAIN AND PARASITE BURDEN OF GOAT KIDS By JOSEPH CHAKANA HAMIE A THESIS SUBMITTED TO THE GRADU ATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2012
2 2012 J oseph C hakana H amie
3 To my special Mom and Dad (Anger in e Soko and Benet Mzomera Hamie) for their moral and spiritual support throughout my life and the entire period of my Master of Science ( M.S. ) degree program
4 ACKNOWLEDGMENTS I would like to thank the Department of Animal Sciences, University of Florida for according me the opportunity to ca rry out the research reported in this thesis with their facilities. My sincere and special thanks and appreciation go to Dr. Adegbola T. Adesogan, my major advisor, for his tireless and sound technical guidance and support throughout the entire research en deavor. I am also grateful to my committee members, Drs. Lynn Sollenberger and Susan Chikagwa Malunga for their assistance with various aspects of my studies. This work and my entire Master of Science ( M.S. ) degree study program would not have been possi ble without the financial support from the U nited S tates A gency for I nternational D evelopment (USAID) Initiative for Long Term Training and Capacity Building (UILTCB) program and the Malawi Government, for which I am very grateful. I also specially thank m y friend indeed, Miguel Urbano Zarate, for his support during the entire study. His time, jokes, games and particularly his unparalleled hard work are highly appreciated. I am also grateful to everyone who rendered their support in one way or another, inc luding Evandro Muniz, Yeonjae Jang, Jan Kivipelto Oscar Queiroz, Juan Jose Romero, Kathy Arriola, Lucas Paranhos, Natalie Forman, and Joseph Sapora, just to mention a few.
5 TABLE OF CONTENTS Page ACKNOWLEDGMENTS ................................ ................................ ................................ .. 4 L IST OF TABLES ................................ ................................ ................................ ............ 7 L IST OF FIGURES ................................ ................................ ................................ .......... 8 L IST OF A BBREVI A TIONS ................................ ................................ ............................. 9 CHAPTER 1 I NTRODUCTION ................................ ................................ ................................ .... 12 2 LITERATURE REVIEW ................................ ................................ .......................... 15 Goat Production and Consumption ................................ ................................ ......... 15 History of Goat Domestication ................................ ................................ .......... 15 Ecological Distribution and Adaptation of Goats ................................ ............... 15 Benefits of Raising Goats ................................ ................................ ................. 16 Goat Production Systems ................................ ................................ ................. 17 Growth of the Uni ted States (US) Goat Industry ................................ ............... 17 Characteristics of Goat Operations in the US ................................ ................... 18 Consumption Preferences and Health Benefits of Goat Meat .......................... 19 Challenges of the US Goat Industry ................................ ................................ 20 Factors Influencing Intake in Ruminant Animals ................................ ..................... 21 Physiological Factors Affecting Feed Intake ................................ ..................... 22 Environmental Factors Affecting Feed Intake ................................ ................... 22 Forage or Feed Availability ................................ ................................ ............... 24 Dietary Factors Affecting Feed Intake ................................ .............................. 25 Gastrointestinal Hormones Affecting Feed Intake ................................ ............ 27 Supplementation of Forage Diets ................................ ................................ ........... 29 Limitations of Warm Season Grass Pastures for Ruminant Animal Production ................................ ................................ ................................ ..... 29 Crude Protein Supplementation of Forage Based Diets ................................ ... 30 Ruminal Microbial Protein Synthesis ................................ ................................ 32 Optimizing Protein Supplementation ................................ ................................ 33 Using Legumes as Protein Supplements ................................ ......................... 34 Effects of Gastrointestinal Nematode In fection on Animal Performance and Health ................................ ................................ ................................ .................. 35 Haemonchus contortus Infection in Ruminants ................................ ................ 35 Lifecycle of Haemonchus contortus ................................ ................................ .. 36 Climatic Conditions Favoring the Development of Haemonchus contortus ...... 37 Fecundity of Haemonchus contortus ................................ ................................ 37 Clinical and Pathophysiological Signs of H. contortus Infection ....................... 38 Production and Economic Losses from Haemonchosis ................................ ... 38
6 Anthelmintic Resistance to Gastrointestinal Nematodes ................................ ......... 39 Monitoring Gastrointestinal Nematodes with the FAMACHA Chart ........................ 40 Challenges Associated with Using the FAMACHA Chart ................................ 42 Immunological Control of Gastrointestinal Nematodes ................................ ........... 43 The Influence of Nutrition on Host Response to Gastrointestinal Nematodes ........ 44 Effects of Condensed Tannins on Nutrient Utilization and Gastrointestinal Nematodes ................................ ................................ ................................ .......... 47 Definition, Classes and Distribution of Tannins in Plants ................................ 47 Condensed Tannin Reactivity with Protein and Other Molecules ..................... 49 Nutritional Benefits of Condensed Tannins in Ruminants ................................ 50 Detrimental Effects of Condensed Tannins on Ruminant Nutrition ................... 52 Differences in Response of Ruminants to Condensed Tannins ....................... 54 Condensed Tannins as Sustainable Alternatives to Anthelmintics ................... 55 3 EFFECT OF SUPPLEMENTING BAHIAGRASS HAY WITH WARM SEASON LEGUME HAYS ON FEED INTAKE, DIGESTIBILITY, NITROGEN RETENTION, BODY WEIGHT GAIN AND PARASITE BURDEN OF GOAT KIDS ................................ ................................ ................................ ....................... 58 Materials and Methods ................................ ................................ ............................ 59 Forage Production ................................ ................................ ............................ 59 Animals ................................ ................................ ................................ ............. 60 Housing and feeding ................................ ................................ ........................ 61 Sample collection ................................ ................................ ............................. 62 Chemical analysis ................................ ................................ ............................ 63 Statistical Analysis ................................ ................................ ............................ 65 Results and Discussion ................................ ................................ ........................... 66 Intake, digestibility and nitrogen retention ................................ ........................ 67 Ruminal fermentation indices and blood metabolites ................................ ....... 69 Parasite burden ................................ ................................ ................................ 70 Indices of anemia and the immune response ................................ ................... 72 Animal performance and indices of resilience ................................ .................. 73 4 CONCLUSIONS ................................ ................................ ................................ ..... 75 LIST OF REFERENCES ................................ ................................ ............................... 85 BIOGRAPHICAL SKETCH ................................ ................................ .......................... 122
7 LIST OF TABLES Table Page 3 1 Chemical Composition of The Bahiagrass, Perennial Peanut, Sericea Lespedeza, Cowpea and Soybean Hays ................................ ............................ 78 3 2 Effects of Supplementing B ahiagrass (BG) Hay with Perennial Peanut (PEA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on Intake of Dry Matter (DMI), Organic Matter (OMI), Neutral Detergent Fiber (NDFI), and Nitrogen (NI) ................................ ................................ ................... 78 3 3 Effects of Supplementing Bahiagrass (BG) Hay with Perennial Peanut (PEA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on Digestibility of Dry Matter (DMD), Organic Matter (OMD), Neutral Detergent Fiber (NDFD) and N itrogen (ND) ................................ ................................ ........ 79 3 4 Effects of Supplementing Bahiagrass (BG) Hay with Perennial Peanut (PEA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on Nitrogen (N) Balance ................................ ................................ .......................... 79 3 5 Effects of Supplementing Bahiagrass (BG) Hay with Perennial Peanut (PEA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on Ruminal Fermentation Indices and Blood Urea Nitrogen (BUN) and Plasma Glucose (PGlu) Concentrations of Goats ................................ ........................... 80 3 6 Effects of Supplementing Bahiagrass (BG) Hay with Perennial Peanut (PEA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on G astrointestinal (GIN), Eimeria sp. (EIM) Fecal Egg Counts (FEC), Packed Cell Volume, FAMACHA Scores and Haptoglobin Concentration of Goats ........ 81 3 7 Effects of Supplementing Bahiagrass (BG) Hay w ith Perennial Peanut (PEA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on The Performance of Goats ................................ ................................ ........................ 82 3 8 Effects of Supplementing Bahiagrass (BG) Hay with Perennial Peanut (P EA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on Indices of Resilience of Goats to Parasitism ................................ ...................... 83
8 LIST OF FIGURES Figure Page Figure 3 1 Effects of Supplementing Bahiagrass (BG) Hay with Perennial Peanut (PEA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on Haptoglobin Concentrations Means at the Wee k ndicated differed (P < 0.05). Error bars are standard errors ................................ ................................ 84
9 LIST OF ABBREVIATION S ADF Acid Detergent Fiber ADG Average Daily Gain ADL Acid Detergent Lignin BSc Bachelor of Science BW Body w eight BUN Blood Urea N itrogen CWP Cowpea CCK Cholecystokinin CT Condensed Tannins DARS Department of Agricultural Research Services DMI Dry Matter Intake EAT Effective Ambient Temperature FAMACHA FAffa MAlan CHArt FEC Fecal Egg Count FL Florida GIN Gastro Intestinal Nematodes GH Growth Hormone H hydrogen HT Hydroly z able Tannins Kg kilogram LCFA Long Chain Fatty Acids LES Sericea L espedeza LS Serecea Lespedeza
10 M.S. Master of Science NASS National Agricultur al Statistics Service NDA National Development Aency NDF Neutral Detergent Fiber NH 3 N Rumen Ammonia nitrogen NY NewYork NRC National Research Council NSC Non Sutructural Carbohydrates PCV Packed Cell Volume PEA Peanut PGlu Plasma Glucose pH power of Hydrogen PUN Plasma Urea Nitrogen RDP Rumen Degradable P rotein SOY Soybean TDN Total Digestible Nutrients THI Temperature Humidity index UILTCB Initiative for Long Term Training and Capacity Building US United States USAID Un ited States Agency for International Development USDA United States Department of Agriculture UV Utra Violet VFI Voluntary Feed Intake
11 Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Req uirements for the Degree of Master of Science EFFECT OF SUPPLEMENTING BAHIAGRASS HAY WITH WARM SEASON LEGUME HAYS ON FEED INTAKE, DIGESTIBILITY, NITROGEN RETENTION, BODY WEIGHT GAIN AND PARASITE BURDEN OF GOAT KIDS By J oseph C hakana H amie December 2012 C hair: Adegbola T. Adesogan Major: Animal Sciences The study first determined effects of supplementing bahiagrass (Paspalum notatum Flgge; BG) hay with legume hays on feed intake, digestibility, and nitrogen (N) retention. Further, the study examined ef fects of the diets on goat performance and parasite burden. Forty Boer Spanish Kiko goats weighing 24.3 9.8 kg were dewormed, stratified by body weight and randomly assigned to diets of bahiagrass hay supplemented without or with (50% of diet dry mat ter, DM) perennial peanut (Arachis glabrata Benth.) (PEA), soybean [Glycine max (L.) Merr.] (SOY), cowpea [Vigna unguiculata (L.) Walp.] (CWP), or sericea lespedeza (Lespedeza cuneata Dum. Cuors. G. don) (LES] hay. Diets were fed ad libitum for 16 days of adaptation and 7 days of total urine and feces collection. G oats were then placed on BG pasture from d 24 to 66 to allow natural infection with H contortus L3 larvae and coccidian oocysts After d 42 on parasite infested BG pasture, goats were fed the sam e diets for 49 days. Supplementation with LES and PEA increased (P < 0.10) intakes of DM, NDF and CP and N retention. Dry matter intake was increased by LES and PEA (P = 0.01) but ADG was not affected by diet. The LES, SOY and PEA diets reduced gastrointe stinal parasite fecal egg counts by 58.6, 31.0 and 25.3% (P = 0.01, 0.06 and 0.11, respectively).
12 CHAPTER 1 INTRODUCTION Goat ( Capra hircus ) production is rapidly increasing in the United States (US) principally due to high minority or ethnic demand for g oat meat and to a lesser degree, goat milk (Maxey, 1993; Pinkerton et al., 1994). Over 70% of the goats in the US are produced in Texas, the Southeast (Tennessee, Georgia, Kentucky, North Carolina, Florida and Alabama), the Midwest (Oklahoma, Missouri) and California (Solaiman, 2007). Goat farming has potential to produce good economic returns due to high reproductive rates, low cost of breeding stock and the ability of goats to thrive on native pastures (Haenlein, 1992). Bahiagrass ( Paspalum notatum Fl gge) is the major pasture grass used by the livestock industry in Florida as well as the Southern Coastal Plains of Georgia and Alabama (Blount et al., 2001). The yield of bahiagrass is normally sufficient to meet intake requirements of most ruminant live stock during the grazing season; however, the quality is insufficient for growing or lactating ruminants due to low dry matter (DM) digestibility and crude protein (CP) concentration (Duble et al., 1971; Johnson et al., 2001; Redmon, 2002). Supplements are often necessary for optimal growth of goats and because protein is usually limiting in grass based diets, protein supplementation usually improves goat production on warm season grasses (Ahmed and Nour, 1997; Ott et al., 2002). However, grain based comme rcial supplements may not be economical for growing and finishing meat goats. This is particularly true in Florida because most grains are imported into the state at significant cost. In addition, feeding these traditionally high starch supplements may le ad to reduced ruminal pH and fiber digestibility (Garces Yepez et al., 1997). Legumes are alternative protein sources to
13 commercial supplements in ruminant rations and inter seeded grass legume pastures can be used to extend the grazing season and increas e nutrient supply to grazing livestock thereby decreasing feed costs (Leep et al., 2002; Muir, 2002). Gastrointestinal nematodes (GIN), particularly Haemonchus contortus are one of the most important disease constraints to small ruminant productivity in the world (Over et al., 1992; Perry et al., 2002) and they present the greatest danger to the viability of the goat industry in the southeastern region of the United States (Leite Browning, 2006). Control of GIN in ruminants has largely been based on suppr essive or therapeutic use of drugs combined, where practical, with grazing management strategies (Coop and Kyriazakis, 2001). However, reliance on such treatments has resulted in widespread anthelmintic resistance in goats, sheep and cattle in many areas o f the world (Prichard, 1994; Waller, 1994, 1997). Most parasite genera are resistant to one or more of the broad spectrum anthelmintic drug groups (i.e. the benzimidazoles, the levamisole morantel group and the avermectins) on the market (Van Wyk et al., 1 987; Van Wyk and Malan, 1988; Watson and Hosking, 1990; Waller, 1994). Resistance to such drugs has also been reported in the Southern US (Miller and Craig, 1996; Zajac and Gipson, 2000; Terrill et al., 2001; Mortensen et al., 2003). Therefore, sustainable alternative strategies are needed to reduce the gastrointestinal parasite burden of ruminant livestock in the Southeast. Some recent studies have shown that when fed to goats instead of bahiagrass, sericea lespedeza [ Lespedeza cuneata (Dum. Cours., G. Do n] is an effective dewormer (Min et al., 2004, 2005; Shaik et al., 2004, 2006; Moore et al., 2008; Terrill et al., 2009), which also increased the performance of goats (Min et al., 2003, 2005). However, attempts to grow l espedeza in Florida have been unsu ccessful
14 (A. Blount, personal communication) and the legume is not recommended for Florida (Newman et al., 2010). This study sought to investigate the potential of using warm season legumes adapted to Florida to reduce the parasite burden of goats and enh ance their performance. The objective of the study was to determine the effects of supplementing bahiagrass (cv. Pensacola) hay with hays of perennial peanut ( Arachis glabrata Benth.), soybean [ Glycine max (L.) Merr.], cowpea [ Vigna unguiculata (L.) Walp .], and sericea lespedeza [ Lespedeza cuneata (Dum. Cours., G. Don)] on feed intake, digestibility, N retention, growth performance and reduction of gastrointestinal nematode infestation in goats. A further objective was to examine the effects of the same diets on growth performance, immune response and parasite burden in goats. The hypothesis was that supplementation with these legumes would decrease the parasite burden and increase performance of the goats.
15 CHAPTER 2 LITERATURE REVIEW Goat Production and C onsumption History of Goat Domestication The goat population has increased worldwide during the last three decades and it was estimated at approximately 840 million head in 2008 (Simela and Merkel, 2008). Approximately 95% of goats in the world are meat g oats (Thompson, 2006). Goats were among the earliest animals to be domesticated (Galal, 2005; Melanie et al., 2012). Some authors indicate that the first evidence of goat domestication dates back to 8500 7900 B.C. in the Fertile Crescent region and Zagros Mountains of the Middle East (Taberlet et al., 2008), while others believe the domestication occurred in 10,000 B.C. conditions was possibly one of the reasons they were amon g the first animals domesticated by man for production of meat, milk, skins and fiber (Gall, 1981). Currently, goats are among the most common animals worldwide, and goat meat and milk is highly valued in several parts of the world (Solaiman, 2007). Ecolo gical Distribution and Adaptation of Goats Goats are found in all agro ecological zones from hyper arid to super humid and in the whole range of production systems from intensive smallholder production to very extensive nomadic pastoralist systems (Payne a nd Wilson, 1999), but they are concentrated in the tropics, dry zones and in developing countries (Galal, 2005). Goats exhibit large diversity due to their ability to adapt to different environments and to natural selection under different conditions (Mora nd Fehr et al., 2004). In addition, indigenous goats have developed specific adaptations to survive and be productive
16 under adverse local, management, and environmental conditions. These adaptations make them thrive in traditional, low external input produ ction systems despite facing problems like climate stress, poor quality feed, seasonal feed and water shortages, endemic disease and parasite challenge (IBC, 2004). Benefits of Raising Goats Goat production is attractive because it requires low initial ca pital and maintenance costs and goats can thrive on marginal land and crop residues. Further, goats produce sufficient milk and meat for subsistence and commercial farming and they can be managed by family labor even when it is by women and children (Peaco ck 2005; Papachristoforou and Markou 2006; Semakula et al. 2010). Goat production offers a viable form of sustainable livestock production, particularly for individuals with limited financial resources, land, or physical abilities (Spencer, 2008). Goats are also popular with small holders because of their relatively efficient conversion of feed into edible high quality meat, milk, and hide (Solaiman, 2007). In addition, they require less land to graze and are easier to handle than larger livestock (Tades se, 2004). Small ruminants are an integral part of livestock production in sub Saharan Africa where they are kept mainly for milk, meat, wool, manure, or as an immediate cash source, as savings or for risk distribution (Kosgey et al. 200 8 ). Goats serve a s a living bank for many farmers and they are closely linked to the social and cultural life of resource poor farmers (Workneh, 2000). They provide security in bad crop years or when crop prices are unfavorable in intensive cropping areas (Ehui et al. 2000 ). They are also prolific, needing only short periods to increase flock sizes after catastrophes or in periods of high prices, thus off take rates can respond rapidly to price increases (Ngategize, 1989). Goats are sometimes managed as part of a multi spec ies grazing
17 system with cattle and are highly valued for their ability to control noxious plants (Glimp, 1995). Goat Production Systems Goats are raised under intensive or extensive production systems. Most goats are raised on pasture or native range based extensive systems but small intensive or semi intensive flocks are growing in number. Extensive production systems are common in arid and semi arid regions. Brush and grasses are the main sources of nutrients, and large herds of goats generally range over vast areas. Intensive production usually involves smaller herds and much smaller geographical areas. Animal productivity is greater in such systems because of the higher nutritive value of improved pastures and provision of supplementary concentrates (She lton 1992; Pinkerton 1995). In many parts of the world, meat goat production is dependent primarily on using forages to meet nutritional needs of goats for economic reasons. Goats eat all classes of forage but prefer about 60% browse, 20% grasses and le gumes, and 20% forbes (Pinkerton and Pinkerton, 1996). Luginbuhl et al. (1996) reported that meat goats perform well in production systems when management practices match their eating behavior because being natural browsers, they prefer to source at least half of their daily ration from browse or woody plants. Growth of the U nited S tates (US) Goat Industry Although the US goat industry is still in its infancy (Gelaye and Amoah, 1991), meat goat production has become one of the fastest growing livestock ind ustries in the US and has proven to be a profitable enterprise for many farming families (Bowman, 2003). Meat goat production grew at 3 5% from 2005 until 2009 when it declined slightly (USDA National Agricultural Statistics, 2011). The rapid growth was pr incipally due to
18 high minority or ethnic demand for goat meat, and to a lesser degree, goat milk as well as demand by gourmet restaurants (Maxey, 1993; Pinkerton et al., 1994). High reproductive rates, low costs of breeding stock, and the ability of goats to thrive on native pastures have also made goat farming highly profitable and fueled the growth of the industry (Haenlein, 1992). The majority of the ethnic groups that consume goat meat are from the Mediterranean, Caribbean, Middle East, Southern Europe India, Far East, Africa, Southern Asia, Mexico, South America, and Central America (Solomon 1992). The greatest demand for goat meat in the US is from the eastern US coast, southern California, Michigan Florida and the northwest corridor stretching fro m Washington to Boston (Agricultural Utilization Research Institute, 2001). Most (over 70%) of the goats in the US are produced in the South (Texas), the Southeast (Tennessee, Georgia, Kentucky, North Carolina, Florida and Alabama), the Midwest (Oklahoma, Missouri) and the West (California) (Solaiman, 2007). Characteristics of Goat Operations in the US According to USDA NASS (2011), there were approximately 152,000 goat operations in the US in 2010, and the average herd size of meat goat farms was 20 goat s (USDA NASS, 2011). The total goat inventory in the US on January 1, 2012 was 2.86 million head, (down 4% from 2011), of which 82% were meat goats ( USDA NASS, 2012). Despite significant increases in the domestic harvest, the US is a net importer of goat m eat, and approximately 98% of the imported goat meat originates from New Zealand and Australia (USDA FAS, 2004). Nevertheless, surveys revealed that ethnic minority consumers were willing to spend more for domestically produced chevon
19 instead of purchasin g imports of frozen goat carcasses from other countries ( Agricultural Utilization Research Institute 2001). Sande et al. (2005) reported that with the exception of the South African Boer and New Zealand Kiko, there is no consensus on a meat goat breed in the U S Several other breeds, such as the Spanish, Myotonic (Tennessee fainting goat ), Nubian and Pygmy have been used for meat production in the U S (Luginbuhl 1998, 2000; Melan i e et al., 2012). However, the three dominant breeds of meat goats in the US are the Boer, which originated in South Africa, the Kiko, which was developed from native goats of New Zealand, and the Spanish, which was developed from feral goats originally introduced by the Spanish explorers and settlers in Texas and the southwest US (Shelton, 1990). Seventy percent of meat goat owners produce Boer goats, 43% have Spanish goats and 15% have Kiko goats. The Boer, Spanish, Kiko, Myotonic, Savannah breeds, or any of these breed combinations are ideal meat producers (Spencer, 2008). Con sumption Preferences and Health Benefits of Goat Meat product in the world (Agriculture Alterna tives, 2000; Tradex AgriSystems, 2009). It is often served in specialty dishe s centered on festival or holiday events (Sande et al., 2005). It is particularly widely eaten in Asia, Africa, and the Far East (Devendra, 1990) with a production rate of 3.7 million tons in 2001 (Dubeuf et al., 2003). Food preferences vary between natio nalities, cultures, and religious and ethnic groups. In the US, although chevon offers consumers tasty, lower fat meat than beef or pork, goat consumption is not widespread (Getz 1998). The low consumption rate may be related to the unfamiliarity of goat meat and its intense inherent aroma and flavor
20 (Rhee et al., 2003). Despite the unique flavor and palatability, chevon is a more healthy meat compared to other red meats (Sandes et al., 2005) as it is leaner and has less saturated fat and lower saturated t o unsaturated fatty acid ratios than lamb (Sheridan et al., 2003). Chevon is also lower in fat, cholesterol and saturated fats but higher in protein and iron compared to beef, pork, mutton and poultry (USDA, 1989; Gelaye and Amoah 1991; Johnson, 1995; Sand e et al., 2005). Challenges of the US Goat Industry Despite the high demand for goat meat, there are several challenges facing the US goat industry. The primary constraint s to goat production in the US are production and economic losses due to infection with gastrointestinal nematodes (GIN), particularly the blood feeder Haemonchus contortus (Miller and Craig 1996) as well as the development of widespread anthelmintic resistance (Zajac and Gipson, 2000; Terrill et al., 2001; Mortensen et al., 2003; Kapla n et al., 2007). An additional constraint is the lack of a well established regional or national marketing infrastructure by which goats are distributed from the farm to the consumer. Rather, most goats in the US are sold through livestock auctions or dire ctly from the farm where backyard slaughtering is a common practice (McKenzie Jakes, 2007). Other factors that have slowed the growth of the goat industry include: 1) competition from beef sales, 2) seasonality of demand for goat meat, 3) high marketing co sts, 4) long distances between wholesalers and processors, 5) erratic carcass quality, 6) commercial trade resistance, 7) negative consumer attitudes regarding goat meat, and 8) competition from foreign imports (Pinkerton et al., 1991; 2005).
21 Factors Influ encing Intake in Ruminant Animals Feed intake is one of the most important factors affecting the productivity of ruminant animals. If voluntary intake is too low, the rate of production will decrease, resulting in requirements for maintenance becoming a ve ry large proportion of the metabolizable energy consumed and thus giving a poor efficiency of feed conversion (Forbes, 1995). Factors that regulate dry matter intake (DMI) in ruminants are complex and not understood fully. Nevertheless, accurate estimates of feed intake are vital to predicting the rate of gain and to the application of equations for predicting nutrient requirements of ruminants (National Research Council, 1987). Three types of factors affecting feed intake of ruminants can be distinguished: factors that have to do with the animals, the feed characteristics and environmental factors such as ambient temperature and photoperiod (Ingvartsen et al., 1992; Mertens, 1994; McDonald et al., 1995). In addition, management treatments such as administra tion of exogenous intake potential. Intake is influenced primarily by hunger, which is distressing, and by satiety, which is generally pleasurable (Forbes, 1995). Regulatio n of feed intake and dietary choices combine short term control of feeding behavior related to homeostatic regulation of the body and long term controls that depend on nutritional requirements and body reserves (Faverdin et al., 1995). Recent studies indic ate that to compare intake levels across forages and animal species, the DMI units should be expressed as a percentage of body weight (Sauvant et al., 2006; Decruyenaere et al., 2009). A detailed list of the factors affecting feed intake in a structured fo rmat is presented in
22 Mertens, ( 1994 ) The intent in this section is not to give a detailed review of all the factors affecting intake but to emphasize some. Physiological Factors Affecting Feed Intake eed, species, sex, size, body composition, health, and physiological state. Huge variations in intake levels occur between breeds or individuals within a given breed (Sco t t and Provenza. 1999). Lactating dairy or suckler cows with higher energy requirement s graze more selectively (selecting more bites on green grasses) and more intensively (expressing longer grazing periods) than dry cows (Gibb et al., 1999). Heat stress reduced dry matter intake (DMI) by 22% in multiparous cows versus 6% in primiparous cow s and the difference was attributed to the small body size and lower metabolic rate in primiparous cows (Igono et al., 1985). Lactating animals can increase feed intake by 35 to 50% compared with non lactating animals of the same body weight when fed the s ame diet (Agricultural Research Council, 1980). Environmental Factors Affecting Feed Intake Animal environment is a broad term, which includes both physical and biological components (Gates, 1968). Gwazdauskas (1985) indicated that an external factor havi ng a positive or negative impact on growth, lactation, or reproduction is generally temper ature, contaminants, physiological restraint and management systems. However, of all these factors, environmental heat stress is the most detrimental to the DMI of dairy cattle (Bernabucci et al., 1999). A negative correlation ( 0.63) has been reported
23 bet ween temperature Humidity Index (THI) and DMI (Johnson et al., 1963). Holter et al. (1997) reported a reduction in DMI in Jersey cows when minimum THI exceeded 56 and the response continued until the THI was 72. At temperatures greater than 25 o C, ruminan ts decrease the time spent grazing and they adapt their diurnal grazing behavior to avoid the warmest periods of the day (Baumont et al., 2000). However, Conrad (1985) noted that the extent to which DMI is reduced due to heat stress varies. At temperatures of 15 25 o C, normal feed intake occurs whereas temperatures between 25 35 o C cause noticeable (3 to 10%) reduction in feed intake. Feed intake increases as temperatures falls below the thermoneutral zone. Shijimaya et al. (1986) reported that dairy cattle housed in cold barns in which the daily mean temperatures were 5.5 to 1.5 o C had higher DMI than cattle housed in warm barns with daily mean temperatures of 8.2 to 11.2 o C. Similarly, Koknaroglu et al. (2005a) found that cattle fed in the cold season had higher DMI than in other seasons. Demircan et al. (2007) indicated that in cold environments with ambient temperature below the lower critical temperature for beef cattle, the animals increase their energy intake to maintain proper function of the body bec ause of the increase in metabolic heat production. The increase in energy requirements and energy intake is meant to compensate for greater heat loss due to falling ambient temperature, which resultantly increases appetite and feed intake (Demircan et al., 2007). However, a disruption in feed intake behavior is observed at extremely low ambient temperatures (Forbes, 19 9 6; Young, 1988).
24 Photoperiod has also been reported to affect DMI in ruminants. For example, exposure of lactating cows to longer photoperi ods (16 to 18 hours of light each day) increased DMI compared with those exposed to shorter photoperiods (Dahl et al., 2000; Dahl and Petitclerc, 2003 as cited by Dahl, 2006). Forage or Feed Availability The primary nutritional factor controlling anima l production is the quantity of feed that the animal eats each day when excess feed is offered i.e. voluntary feed intake of diets offered for ad libitum intake (Minson and Wilson, 1994). With grazing cattle, the quantity of forage available can affect f eed intake. The authors of the National Research Council (1987) report reviewed data summarized by Rayburn (1986) and concluded that grazed forage intake was maximized when forage availability was approximately 2,250 kg DM/ha or with a forage allowance of 40 g organic matter(OM)/kg BW. Intake decreased rapidly to 60% of the maximum when forage allowance was 20 g OM/kg BW (450 kg/ha; National Research Council, 1987). However, Minson ( 1990) noted that bodyweight gain by sheep wa s related more closely to gree n (growing) forage allowance than to total forage DM offered. Similarly, Bird et al. (1989) reported that body weight gain by grazing cattle could be modeled more effectively from green pasture mass than from total pasture mass. This is because selective g razing of growing forage may increase in pastures with both growing and senescent material. Cattle eat only small amounts of senescent forage when growing forage is available (Minson, 1990). Hence, effects of forage availability on intake should also accou nt for pasture composition due to the potential for selective grazing.
25 Dietary Factors Affecting Feed Intake Crude protein concentration Several authors have noted that intake is often depressed when the crude protein (CP) content of a diet is below 60 to 80 g/kg of DM (Blaxter and Wilson, 196 3 ; Minson and Minford, 1967). Low quality tropical forages may have CP concentrations lower than 70 g/kg of DM, which is considered the critical threshold for adequate microbial growth on the fibrous carbohydrates of such basal forages (Lazzarini et al. 2009 ). Consequently, the DMI of tropical forages can be limited by their low CP concentrations. It is no surprise that when diets low in protein relative to energy are fed to animals with high protein requirements suc h as rapidly growing young animals or lactating females, intake is limited by protein deficiency (Moore et al., 1999). Supplementation of forages containing low CP concentrations increases forage intake (Paterson et al., 1994) due to increased degradation of potentially degradable fiber (Lazzarini et al. 2009) as well as faster rate of passage of legumes when the supplemental CP is from legumes (Bowman et al., 1991). The increase in forage degradation is largely due to increased supply of N for growth of r uminal microbes that digest the forage (Russell et al., 1990; Van Soest, 1994). Positive forage intake responses to supplemental protein are most common when forage CP concentration is less than 6 to 8% (NRC, 1987). However, supplementation of low CP diet s can either improve intake of a basal diet (Pathirana and rskov, 1995; Abdulrazak et al., 1997) or reduce intake (Getachew et al., 1994), depending on the relative quality of the basal diet and the supplementary feeds.
26 Plant cell wall concentration Ruminants consuming diets high in cell wall concentration often are unable to eat sufficient quantities to meet their energy demands (Jung and Allen, 1995) resulting in reduced performance or loss of wei ght (Burns et al., 1994). Allen (1996) reported that voluntary DMI of forage based diets by ruminants is limited by digesta flow, rate of digestion and digestive tract capacity. Others have noted that intake is limited when animals are fed diets that are high in bulk fill and low in available energy concent ration (Balch and Campling, 1962; Campling, 1970; Bines, 1971; Baile and Forbes, 1974; Mertens, 1994). Fiber has been related to the filling properties of feeds because it ferments and passes from the reticulorumen more slowly than the non fiber constit uents (Jung and Allen, 1995). Van Soest (1965) found that acid (ADF) and neutral detergent fiber (NDF) fractions were negatively correlated to voluntary DMI of sheep consuming all forage diets and that NDF was more highly correlated to voluntary DMI (r = 0.65) than was ADF (r = 0.53) across grasses and legumes. Likewise, Waldo (1986) concluded that the NDF concentration of forage is the best single chemical predictor of voluntary DMI. Mertens (1973) reported that voluntary DMI was related to forage NDF co ncentration as follows: VDMI (g/BW0.75/d) = 128.8 1.09 NDF (g/100 g of DM) for 126 grasses and 61 legumes fed to sheep (r 2 = 0.58). Jung and Allen ( 1995) noted that for nutritional studies and general descriptions of forage quality, NDF is an adequate ch aracterization of the plant material. The value of NDF for characterizing the quality potential of C4 grasses, however, is less clear. The cell walls of forage diets may also affect DMI via their effects on digestion. Lignin is recognized as the major comp onent of the cell wall that limits digestion of the
27 wall polysaccharides in the rumen (Jung and Deetz, 1993). Therefore, forages with low NDF digestibility because of high lignin concentrations may also limit DMI. Fat concentration and type Excess fat inta ke depresses DM digestibility (Palmquist and Jenkins, 1980) and DMI (Choi and Palmquist, 1996; Schauff and Clark, 1992) of lactating cows because fat can inhibit fiber digestion in the reticulorumen (Palmquist and Jenkins, 1980). In addition, it has long b een recognized that fat is a potent stimulator of cholecystokinin (CCK) release (Liddle et al., 1985), which contributes to satiety (Reidelberger, 1994). Feeding high fat diets increased plasma CCK in lactating cows (Choi and Palmquist, 1996) and infusion of unsaturated long chain fatty acids (LCFA) inhibited motility of the reticulorumen in sheep (Nicholson and Omer, 1983). The reduction in rate of digesta passage by supplemental fat could also increase distension and stimulation of tension receptors in th e reticulorumen, possibly reducing DMI (Allen, 2000). Brooks et al. (1954) also reported that feeding excessive unsaturated fatty acids exerts toxic effects on ruminal microbes, which lead to depressed fiber digestion. The type of fat has an effect on the extent to which DMI is affected, with unsaturated fats depressing DMI to a greater extent than saturated fats (Allen, 2000). In a review of several studies, Allen (2000) reported that there was a linear decline in DMI due to fat supplementation in dairy c ow diets such that for every 1% increase in inclusion of tallow or Ca salts of fatty acids in the diet there was a reduction of DMI of 1.2 and 2.5%, respectively. Gastrointestinal Hormones Affecting Feed Intake Several hormonal and paracrine signals ar e secreted from endocrine cells lining the gastrointestinal tract in response to the physiochemical properties of ingested food
28 passing along the lumen. The secreted hormones activate the vagus nerves, which in turn stimulate cells in the brainstem, elicit ing reflexes that control GI function and send signals to other brain areas that cause the individual to stop eating (Rinaman et al., 1995; Moran et al., 2001, 2004). The long term regulation of energy homeostasis and maintenance of a stable body weight a re achieved through effective integration of signals indicating body fat stores, such as those given by insulin and leptin, with signals indicating immediately available energy or what is available from recently ingested food (Woods et al., 1998, 2000; Sch wartz et al., 2000). The short term meal related signals, such as those given by cholecystokinin ( CCK ) are effective in maintaining appropriate meal size such that the daily regulation of energy intake is well coordinated with energy usage and long term bo dy weight (Seeley and Woods, 2003; Woods, 2004). Following its release, CCK elicits multiple effects on the gastrointestinal system, including the regulation of gut motility, contraction of the gall bladder, pancreatic enzyme secretion, gastric emptying an d gastric acid secretion (Grider, 1994; Schwartz et al., 1997). Similarly, glucagon like peptide 1 inhibits gastrointestinal motility, reduces gastrointestinal secretions, and attenuates gastric emptying. It is thought to be a major of nutrients through the course of the gastrointestinal tract (Nauck et al., 1997; Giralt and Vergara. 1999). The ability of circulating gastric leptin to reduce food intake and body weight is well known and several reviews on the subject exist (Ahima et al., 1996; Woods, 1998; Elmquist et al., 1999; Schwartz et al., 2000; Seeley and Woods, 2003). Ghrelin is the first identified circulating hormone that promotes feeding following systemic
29 ad ministration (Hiroshi et al., 2002). Predominantly produced by the stomach, ghrelin stimulates secretion of growth hormone (GH), food intake, and body weight gain when administrated peripherally or centrally (Arvat, et al., 2000; Peino, et al., 2000; Takay a, et al., 2000). Ghrelin activates neuropeptide Y and agouti related protein producing neurons localized in the arcuate nucleus of the hypothalamus (Asakawa, et al., 2001; Kamegai, et al., 2001), which is one of the brain regions of primary importance in the regulation of feeding. Ghrelin has been linked to the anticipatory aspects of meal ingestion because levels peak shortly before scheduled meals in humans and rats and fall shortly after meals end (Cummings et al., 2001). Supplementation of Forage Di ets Limitations of Warm Season Grass Pastures for Ruminant Animal Production In Florida and much of the southern U S bahiagrass ( Paspalum notatum Flgge) and bermudagrass [ Cynodon dactylon (L.) Pers. ] are the main pasture forages (Gates et al., 2001). T he nutritive value of bahiagrass varies with the duration of the regrowth period after cutting or grazing, but average values of 8.3% CP, 50% DM digestibility, and 44.2% ADF are typical (Moore et al., 1991; Redmon, 2002). The digestibility and CP concentra tion of these forages decline as they mature and they become dormant in the fall. Consequently, the quantity as well as the quality of these forages is insufficient to meet the nutrient requirements of growing and lactating cattle in mid to late fall (Dubl e et al., 1971; Williams and Hammond, 1999; Johnson et al., 2001). Others have noted that forages alone are often insufficient to meet the nutrient requirements and exploit the genetic potential of grazing ruminants because of seasonal oscillations in nutr ient concentrations and herbage mass (Galyean and Goetsch, 1993; Owens et al., 1993; Moore et al., 1999). Low quality tropical/subtropical forages may have CP
30 concentrations lower than 70 g/kg of dry matter, which is considered to be the critical threshold for adequate microbial growth on fibrous basal forage (Moore et al., 1999; Lazzarini et al. 2009). This deficiency implies poor utilization of potentially degradable cell walls by ruminal microorganisms and decreases both intake and animal performance (Pa ulino et al. 2008). The low digestibility and high concentration of cell walls in such forages also limit energy availability to animals fed high forage diets. Recycling of N can supply N for ruminal microbial growth when forage or dietary N is limiting ( Van Soest, 1994). However, when recycled N makes up a large proportion of the total supply of rumen degradable protein, the long term protein needs of the animal may be underestimated, resulting in decreased performance (NRC, 1985). Therefore, dietary prot ein supplements are needed to enhance the long term productivity of ruminants fed forages with low CP concentrations. Crude Protein Supplementation of Forage Based Diets Protein supplementation is often necessary for optimal growth of ruminants grazing w arm season pastures or poor quality forages (Ahmed and Nour, 1997; Ott et al., 2002). Datta et al. (1998) reported that dietary CP supplementation of a basal oat ( Avena sativa ) straw based diet increased rumen fluid ammonia N concentration, feed intake, a nd live weight gain in sheep (Datta et al., 1998). In addition, CP supplementation increased packed cell volume, eosinophil counts and antibody responses to H. contortus L3 antigen and decreased fecal worm egg counts in the sheep. Foster et al. (2009) repo rted that supplementation with soybean meal [ Glycine max (L.) Merr.], perennial peanut [ Arachis glabrata Benth), annual peanut [ Arachis hypogaea (L.)], and cowpea [ Vigna unguiculata (L.) Walp.] hay increased intake of DM, OM, and N, N digestibility and ret ention, and concentration of ruminal ammonia N (NH 3
31 N) when supplemented to bahiagrass hay. Moore et al. (1999) analyzed a database of 66 publications on 126 forages (73 harvested and 53 grazed) and a total of 444 comparisons between a control, unsupplemen ted and supplemented treatments. They stated that 202 comparisons reported increased forage digestibility while 258 publications reported increased voluntary intake with supplementation. They also noted that the greatest increases in gain were with improv ed forages, supplements with greater than 60% TDN, and supplemental CP intake greater than 0.05% of body weight. In addition, supplements increased voluntary forage intake when the forage TDN:CP ratio was > 7, indicating a N deficit. Factors affecting t he outcome of protein supplementation include the protein concentration of the basal forage, the amount, type (true protein versus non protein N) and ruminal degradability of the protein, the amount and fermentability of the energy supplied, the physiologi cal state of the animal, the protein to sulfur ratio (Hunter, 1991), and the adequacy of other nutrients in the diet. Positive responses to supplemental protein are usually observed when the CP concentration of the basal forage is less than 6 to 8% (Campl ing, 1970; Kartchner, 1981). Paterson et al. (1994) reported that with forages containing low protein concentrations (<7 % CP), a major positive response to protein supplementation occurs due to satisfying minimal ruminal microbiological requirements for N and possibly by providing specific amino acids and or carbon chains. Protein supplements often have little effect on feed intake of cattle consuming forages with CP concentrations above approximately 6% (Mathis et al., 2000) but the critical limit may be greater in growing goats whose minimum dietary protein requirement for maintenance is 6.0 to 8.5% depending on age and type (Fernandes et
32 al., 2007; NRC 2007). In some cases, protein supplementation of low quality forages may not increase animal performan ce if the resulting increase in total diet consumption Ruminal Microbial Protein Synthesis Proteins reaching the small intestine of the ruminant are derived from three sourc es: (a) dietary protein which has escaped breakdown by rumen microbes; (b) protein contained in bacterial and protozoal cells which flow out of the rumen (microbial protein) and (c) endogenous proteins contained in sloughed cells and secretions into the ab omasum and intestine (Cheeke, 2005). Microbial protein is a consistent (Schwab, 1996) high quality protein source with a balanced amino acid profile (Clark et al., 1992) and it is relatively less expensive to produce compared to other protein sources. Ther efore, optimizing microbial protein synthesis should increase the efficiency of N utilization and reduce N urinary excretion, which constitutes a major source of N pollution from livestock farms. Factors that influence ruminal fermentation and microbial protein synthesis include the amount and type of supplemental protein, carbohydrate sources and availability in the rumen, and ruminal pH (Bateman et al., 1999). Dietary rumen degradable protein is converted mainly to ammonia in the rumen where it is the p rincipal starting substrate for microbial protein synthesis. Bryant and Robinson (1963) found that 92% of ruminal bacterial isolates could utilize ammonia as the main source of N. This is also supported by Russell et al. (1992) who reported that cellulolyt ic bacterial utilize ammonia as the primary N source. Nolan (1975) and Leng and Nolan (1984) reported that 50% or more of microbial N is derived from ammonia and the rest is from peptides and amino acids. More recent work suggests that the minimum contrib ution to microbial N from ammonia
33 is 26% when high concentrations of peptides and amino acids are present but it increases to a potential maximum of 100% when ammonia is the sole N source ( Wallace 1997 ). An adequate rumen ammonia concentration is a prereq uisite for optimal ruminant microbial growth and fermentation and for maximal flow of microbial amino acid to the small intestine (Datta et al., 1998). The in vitro rumen fermenter studies of Satter and Slyter (1974) showed that microbial protein yield was limited at rumen ammonia concentrations of 2 mg/dL and maximized at 5 mg/dL. However, in vivo studies showed that microbial protein production was not maximized until rumen ammonia reached 10 (Hume et al. 1970) or 29 mg/dL (Miller 1973). Broderick (200 7) explained that the relatively low ammonia levels required by ruminal organisms in the in vitro studies might be because they used soluble substrates, whereas greater concentrations are required in situ and in vivo, particularly when bacteria are associa ted with particulate substrates with very low ammonia concentrations in such niches (Oldle and Schaefer, 1987). Optimizing Protein Supplementation In ruminants, the conversion of dietary N into edible protein products such as meat and milk is very low (2 0 30%), with the majority of dietary N (70 80%) being excreted in feces and urine. Microbial fermentation of N can result in inordinately high amounts of ammonia. When rapidly degraded energy sources are available, NH 3 as well as amino acids and peptides i n the rumen stimulate microbial growth rate and yield of microbial protein (Russell et al. 1983; Chen et al. 1987; Argyle and Baldwin 1989; Cruz Soto et al. 1994). However, if the RDP supply is high or if inadequate fermentable carbohydrates are availab le, excess NH 3 N that is not utilized for microbial growth flows out of the rumen or is absorbed through the rumen wall and transported via the portal
34 vein to the liver (Van Soest, 1994). In the liver, absorbed NH 3 N is converted to urea via the urea cycle and is either recycled through the blood and saliva back to the rumen (rskov, 1992; Van Soest, 1994) or is excreted via the kidneys into urine. Urine N excretion represents a waste of ingested N and contributes to environmental pollution through leachin g of N, degradation of downstream water quality and eutrophication of coastal marine ecosystems, development of photochemical smog, and increased emissions of nitrous oxide, a potent greenhouse gas (Vitousek et al., 1997). Ruminants consuming excess rum en degradable protein can suffer malaise and decrease intake as a result of high levels of ammonia in the blood (Prins and Beekman 1989). This is because when ammonia absorbed in the rumen exceeds the capacity of the liver to convert it into urea, it pass es into the peripheral circulation where excessive ammonia is toxic (Chalupa et al. 1970, Prior et al. 1970, Femandez et al. 1990, Schelcher et al. 1992). Therefore, strategic protein supplementation aims to optimize the level and efficiency of microbi al protein synthesis in order to increase animal performance and to prevent ammonia toxicity and reduce urinary N excretion and the attendant environmental problems. Using Legumes as Protein Supplements Legumes are often more digestible than warm season grasses because they contain lower structural carbohydrate concentrations as well as greater CP and non structural carbohydrate (NSC) concentrations (Ball et al., 2002). Consequently, legumes can be used as alternative protein sources to commercial supplem ents in ruminant rations. Supplementary legumes can be of particular value in providing CP to small ruminants when low quality roughages are offered (Goodchild and McMeniman, 1994). Most of the protein in forage legumes is in the form of rumen degradable p rotein, which
35 can be rapidly converted to NH 3 N in the rumen (Broderick, 1995). Therefore, dietary intake of legumes often stimulates ruminal microbial growth and thus increases the supply of microbial protein to the small intestine (Mupwanga et al., 2000a ). Legume supplementation can also improve N retention by the ruminant when grass diets are fed that do not meet ruminant energy and N requirements (Mosi and Butterworth, 1985; Matizha et al., 1997). Effects of Gastrointestinal Nematode Infection on Anim al Performance and Health Gastrointestinal nematode (GIN) parasites are one of the most important disease constraints to small ruminant productivity in tropical and temperate regions of the world (Over et al., 1992; Perry et al., 2002). These parasites pr esent the greatest danger to the goat industry in the southeastern US (Leite Browning, 2006), where the warm, moist climatic conditions are ideal for growth of GIN larvae on pasture (Miller, 1996). Some of the main parasites of veterinary importance in s mall ruminants belong to the phylum Nemathelminthes (roundworms or nematodes), which include the following superfamilies: Trichostrongyloidea, Strongyloidea, Metastrongyloidea, Ancylostomatoidea, Rhabditoidea, Trichuroidea, Filarioidea, Oxyuroidea, Ascarid oidea and Spiruroidea (Sissay, 2007). However, the GIN of greatest importance in small ruminants are members of the order Strongylida which contains Trichostrongyloidea, Strongyloidea, Metastrongyloidea and Ancylostomatoidea but most of them belong to th e Trichostrongyloidea superfamily. Haemonchus contortus Infection in Ruminants Haemonchosis is a predominant, highly pathogenic and economically important disease of sheep, deer and goats caused by Haemonchus contortus (Mortensen et al., 2003). Haemonch us contortus was first described in 1803 by Karl Rudolphi (Soulsby,
36 worm. This blood sucking abomasal nematode parasite of sheep and goats belongs to the superfamily Trichostr ongyloidea (Urquhart et al., 1996). It is the single most important nematode pathogen of small ruminants in the developing world (Perry et al., 2002). Fourteen types of morphologically diverse Haemonchus contortus females have been described (Roberts et a l., 1854; Chitwood, 1957). Based on vulvar morphology, Chitwood (1957) grouped the female types int o those with a) a linguiform process, b) a knoblike projection, and c) no vulvar projections, and suggested that females with the linguiform process and thos e without projections are the basic types whereas females with the knoblike projection are their hybrids. Lifecycle of Haemonchus contortus Haemonchus and all other economically important Strongyloidae parasites of small ruminants have direct life cycles t hat require no intermediate hosts (Sissay, 2007). According to Sissay (2007), the mature worms breed inside the host and lay eggs which pass through the host and are shed in the feces. Eggs then hatch into first stage larvae (L1) and moult into second stag e larvae (L2) under appropriate temperature and humidity. The larvae feed on bacteria but need moisture to develop and move. The second stage larvae (L2) moult into infective larvae (L3), which migrate out of the feces and up blades of grass where they are ingested by grazing ruminants. Following ingestion of L3 larvae, the worm burrows into the mucosal layer of the stomach and moults into fourth stage larvae (L4) within 2 3 days, and subsequently into adult parasites after 10 14 days (Soulsby, 1982; Hale, 2006; Coffey et al., 2007). Adult worms attach to the abomasal wall and penetrate the mucus membrane into blood capillaries to
37 ingest blood (Soulsby, 1965). The life cycle takes about 17 to 21 days. Each developmental stage of H. contortus may be considere d a separate organism due to differences in behavior, environmental niche and the stage specific antigens produced (Balic et al., 2000a, b). The successful transmission however is dependent on the prevailing environmental conditions (Veglia, 1915). Climati c Conditions Favoring the Development of Haemonchus contortus Haemonchus contortus is frequently found in tropical and subtropical regions where the conditions for its survival are optimal. However, the parasite has also become a growing problem in temper ate regions (Waller et al., 2004). High humidity, at least in the microclimate surrounding the feces and the herbage, is essential for larval development and survival. A mean monthly temperature of 18C and a minimum monthly rainfall of 50 mm (Gordon, 194 8) are the lower environmental limits for development of the egg to the L3 stage, whereas optimal conditions are a temperature of 28C with humidity greater than 70% (Rossanigo and Gruner, 1995). Silverman and Campbell (1959) observed that there is little or no development of eggs to larvae at temperatures below 9C (Silverman and Campbell, 1959). Fecundity of Haemonchus contortus Haemonchus contortus females are very prolific, each capable of produc ing as many as 5,000 eggs daily Coyne and Smith (1992) reported that parasite fecundity was independent of the intensity of infection but fecundity increased sigmoidally to a maximum level during the initial period of infection. The high fecundity leads to rapid contamination of pastures with larvae such that high levels of ingestion can lead to death (Roberts and Swan, 1982).
38 Clinical and Pathophysiological Signs of H. contortus Infection Haemonchus contortus infection can follow different clinical courses, ranging from chronic cases in older animals with lo w parasite burdens to acute and often fatal outbreaks in young animals or those not previously exposed to the parasite. The pathophysiology of Haemonchus infections includes different digestive tract disorders, such as loss of appetite, intestinal motility and flow alterations, increased gastric pH, and impaired energy and protein metabolism (Holmes, 1987; Fox 1997; Hoste, 2001). However, the main pathogenic mechanism is related to haematophagous feeding of the pre adult and adult stages on the abomasal muc osa, which leads to anemia, hypoproteinemia, edema and death in heavily infected animals (Rowe et al., 1988; R ahman and Collins, 1990). It has been estimated that each worm sucks about 0.05 ml of blood per day by ingestion or seepage from lesions (Urquhar t et al. 2000). Additional signs of infection include diarrhea, dehydration, peripheral and internal fluid accumulation, anorexia, depression, and loss of condition (Miller et al., 1998; Leit Browning, 2006). Production and E conomic L osses from H aemonch osis Sheep and goats, and particularly young lambs and kids, are highly susceptible to infection with H. contortus which is responsible for about 30 50% of mortality in kids and lambs in situations where few or no control measures are used (Baker, 1997; A umont et al., 1997). Another major problem is production losses due to decrease in weight and growth of the host animal that in turn lead to economic losses. Infested goats have lower growth rates, markedly reduced reproductive performance, and higher rate s of illness and death (Leit Browning, 2006). Using trickle infections of abomasal and intestinal nematodes or concurrent infections, it has been established that
39 parasitism can impair live weight gain, soft tissue deposition, skeletal growth, and milk and wool production (Parkins and Holmes, 1989; Poppi et al., 1990; Holmes, 1993; Sykes, 1983, 1994). A reduction in voluntary feed intake and reduced feed efficiency are some of the major factors contributing to the reduced performance of parasitized ruminant s (Sykes and Coop, 1976; Symons and Hennessy, 1981; Coop et al., 1982; Sykes et al., 1988). Anthelmintic Resistance to Gastrointestinal Nematodes Indiscriminate and excessive use of anthelmintics has led to the development of severe anthelmintic resistanc e on sheep and goat farms in many parts of the world (Van Wyk et al., 1999). Therefore, many parasite genera are resistant to one or more of the three broad spectrum anthelmintic groups on the market (the benzimidazoles, levamisole morantel drugs and the avermectins) (Van W y k et al., 1987; Van Wky and Malan, 1988; Watson and Hosking, 1990; Waller, 1994). In the southern US, frequent use of anthelmintics has resulted in selection of worm populations that are resistant to these drugs (Miller and Craig, 1996; Zajac and Gipson, 2000; Terrill et al., 2001; Mortensen et al., 2003). Selective treatment of the most infected and or the most anemic animals could prevent the development of drug resistance. Studies indicate that a practical approach to reducing selecti on pressure for anthelmintic resistance is to drench only a portion of the flock, leaving many untreated animals in which unselected, non resistant worms survive and propagate (Bisset et al., 1994; Besier, 1997). The untreated animals would continue to dep osit the eggs of anthelmintic susceptible worms on the pasture, which would maintain a reservoir of susceptible larvae in refugia, thereby slowing down the development of anthelmintic resistance (Besier, 1997). The use of selective drenching however, requi res a reliable means to differentiate between
40 those animals, which, if left untreated, would be at risk of developing severe helminthosis and possibly dying, and those that would be in no immediate danger (Bath et al., 2001). Monitoring Gastrointestinal N ematodes with the FAMACHA Chart It is well known that during the course of fatal haemonchosis, the color of the conjunctivae of ruminants changes from the deep red of a healthy ruminant, through shades of pink to practically white, as a result of a progre ssively worsening anemia (van Wyk et al., 2002). Hematocrit measurements are generally accepted as providing the most accurate indication of the severity of anemia and they are also positively correlated (at least at the phenotypic level) with most other i ndicators of resistance/resilience to parasites (Bath et al., 2001). However, the analytical process involved in measuring hematocrits is time consuming and requires specialized equipment, which few if any farmers possess (Bath et al., 2001). In the earl y 1990s, a trial was conducted at Badplaas (Mpumalanga) in South Africa to test whether it was possible to evaluate the degree of clinical anemia caused by Haemonchus infection clinically by classifying the color of the ocular mucus membranes (Malan and Va n Wyk, 1992; Malan et al., 2001). Based on the results, a color chart called the FAMACHA chart) was developed (Bath et al., 1996). The colors were classified as red (category 1), red pink (category 2), pink (category 3), pink white (category 4) or white ( category 5) ( Malan and Van Wyk, 1992; Bisset et al., 2001 ). The name of the system was coined in honor of its originator, Francois (Faffa) Malan: FAffa MAlan CHArt (Van Wyk et al., 1997b). Clinical use of the chart for evaluation was refined in a series of subsequent trials by standardizing the five informal descriptive categories into five specified 27% for category 2, 18 22% for
41 category 3, 13 Wyk et al., 1997 a ). T he expected mucous membranes colors of the conjunctivae of sheep with hematocrits of 35% (category 1), 25% (category 2), 20% (category 3), 15% (category 4) and 10% (category 5) is depicted in the FAMACHA chart ( Malan and Van Wyk, 1992 ; Bisset et al., 2001 ) Each animal was classified into one of the following conj unctiva color categories: red, red pink, pink, pink white or white (categories 1 5, respectively, in later trials) (Malan and Van Wyk, 1992; Van Wyk et al. 1997 a ; Malan et al. 2001). The diagnosis is done by holding the FAMACHA color chart next to the eye, and moving it up and or down till one of the color bars on the chart matches the color of the exposed conjunctiva. The feasibility of grading the degree of anemia clinically in conjunctiva mucous membranes was confirmed by both photographing the mucou s membranes and determining the hematocrit of sheep, which ranged from very healthy to extremely anemic (Malan and Van Wyk, 1992; Bath et. al., 1996; Van Wyk, et al., 1997 a ; Malan et al., 2001). Several studies have proved the suitability of the FAMACHA system as an indicator of parasite infection in sheep and goats (Malan et al., 2001; Van Wyk and Bath, 2002; Vatta et al., 2002 a, b; Kaplan et al., 2004; Ejlertsen et al., 2006). When seven methods of frequent examination to identify and treat only ani mals unable to w ithstand a worm challenge were compared, the FAMACHA system was identified as the most useful criterion for treatment of hematophagous worms (Van Wyk et al., 2002), followed by body condition score (Cottle, 1991), and then by weighing with a computerized electronic scale (Van Wyk et al., 2002). In a review article, van Wyk et al.
42 (2002) concluded that the clinical evaluation of anemia using the FAMACHA system is sufficiently reliable, both in its specificity and sensitivity, to be a useful adjunct to other measures for managing haemonchosis. In their work with relatively small numbers of goats owned by resource limited (small scale) farmers, Vatta et al. ( 1999, 2001) reported that the best sensitivity and specificity (67 69%) for correctly identifying goats requiring treatment for haemonchosis (< 18% hematocrit) was achieved when animals in FAMACHA categories 3, 4 and 5 were considered to be in need of treatment. Malan and Van Wyk ( unpublished ob servations, 1991) noted that the hematocrits of sheep infected with H. contortus dropped by up to 7 percentage points in 7 days. Thus, an animal with a relatively slight degree of anemia could be on the brink of death in just over a week (van Wyk et al., 2002). The explosive nature of outbreaks of w orm infection (Rose, 1970) makes it necessary to evaluate the severity of worm infection at short intervals during peak worm infestation seasons that can last for as long as 4 5 months (Horak and Louw, 1977; Horak, 1978). The FAMACHA evaluation system all ows frequent, cheap and easy monitoring of the worm infection status of animals, and therefore offers a simple on farm alternative to hematocrit measurements and it is also useful for making animal selection and culling decisions (Bath et al., 2001). Chall enges Associated with Using the FAMACHA Chart In situations where animals are infected with multiple parasites with no predominant species present, the FAMACHA chart might not be appropriate to identify infected animals because of the lack of a blood fee ding parasite (Moors and Gauly, system is that only five categories are assigned, whereas hematocrit values may vary from 8 to over 40%. Therefore, a FAMACHA category that is a ssigned to an animal in
43 which the hematocrit falls on or close to the somewhat arbitrary division between FAMACHA categories could almost equally correctly be assigned to either the higher or the lower FAMACHA evaluations can therefore occur. Bath et al. (2001) mentioned anecdotal evidence that the range of conjunctiva colors is narrower in goats than in sheep, therefore making the FAMACHA system more difficult to apply to goats. Kaplan et al. (2004) observe d that although FAMACHA sounds easy to use, experience in South Africa and the southern U S suggests that proper training of farmers is required to effectively use the method. Bath et al. (2001) also reported that there is a potential danger that persons using the FAMACHA system might become complacent concerning worm infection and therefore cautioned that it should be kept in mind that the system can identify only infection by haematophagous worm species. Unless recognized in time, the presence of a spec ies such as Oesophagostomum columbianum can wreak havoc, as it has a more intense effect on the production of the sheep compared with Haemonchus which is deadly but not nearly so limiting to the growth of animals. Therefore, they emphasized that the FAMAC HA clinical assay should not be used as the only indicator of worm prevalence in a worm control strategy but rather as part of an integrated approach to worm control. Immunological Control of Gastrointestinal Nematodes Infection in ruminants is predominan tly regulated by acquired immunity (Adams, 1989) which controls the impact of GIN on lifetime productivity of grazing animals (Van Houtert and Sykes, 1996). The mechanism of resistance to infection is thought to involve the immunological exclusion of H. co ntortus larvae from the mucosal surface of the abomasum following infection (Miller et al., 1983; Barger et al., 1985; Jackson et al., 1988) and an increase in the mortality rate of adult parasites (Smith, 1988; Coyne et al.,
44 1991b). There is also an initi al loss of L3 larvae due to their failure to exsheath in the rumen (Dakkak et al., 1981). Additional effects of host immunity on GIN include inhibition of establishment of L3 larvae, arrested development, stunting, reduced egg production and expulsion of e stablished worms (Stear et al., 1995; Strain and Stear, 2001; Lacroux et al., 2006). The development of immunity is also influenced by many other factors such as gender, age and dietary protein con centration (Abbott et al., 1988; Holmes, 1985, 1988; Dobson and Bawden, 1974; Bown et al., 1991) and age at weaning (Spedding et al., 1963). The Influence o f Nutrition on Host Response to Gastrointestinal Nematodes Parasite infection, particularly with GIN, has a major effect on the efficiency of production of gr azing ruminants (Sykes, 1994). This is because nematodes impair animal productivity through reduction in voluntary food intake and or reduction in the efficiency of nutrient absorption and utilization (Coop and Kyriazakis, 2001). A common feature of many g astrointestinal parasitic infections is an increased loss of endogenous protein into the gastrointestinal tract, which is partly attributable to increased leakage of plasma protein, increased sloughing of epithelial cells and increased secretion of mucopro teins (Poppi et al., 1986; Bown et al., 1991; MacRae, 1993; Holmes, 1993). The amount of non reabsorbable endogenous nitrogen leaving the terminal ileum of parasitized sheep can be as high as 4 5 g N /day (Poppi et al., 1986; Bown et al., 1991) and this is largely responsible for the reduction in protein retention in parasitized ruminants (Poppi et al., 1986; Kimambo et al., 1988; Rowe et al., 1988). Some of the protein passing into the lumen of the gastrointestinal tract is reabsorbed, depending on whether the lesions are in the anterior or the distal tract and on whether there is adequate compensatory absorptive capacity (Coop and Holmes, 1996), but, even so,
45 recycling of N has an energy cost. Pair feeding studies have shown that the gross efficiency of us e of metabolizable energy for energy deposition is decreased by both abomasal and intestinal infections (Sykes and Coop, 1976; 1977; Sykes, 1983). Earlier reports indicate that overall there is a net movement of protein from productive processes such as m eat, bone, milk and wool production into the synthesis of plasma proteins and repair of the gastrointestinal tract and mucus secretion in parasitized animals (Steel et al., 1982; Symons, 1985; Bown et al., 1986). Consequently, the repair processes have an adverse effect on protein metabolism in other tissues (Yu et al., 2000), thus reducing growth and reproduction. Coop and Kyriazakis (1999) proposed a nutrient partitioning priority framework of scarce nutrients such as protein in host animals and suggested maintenance of body protein has the highest priority for nutrient allocation because it guarantees animal survival in the short term. They indicated that growth and reproduction have the second highest priority because they ensure the preservation of the Functions regulating the parasite population (expression of immunity) will be greatly influenced by host nutrition, because they are likely given a lower priority for a scarce resource allocation than the functio ns of maintenance, growth or reproduction (Coop and Kyriazakis, 1999). Nutrition can affect the ability of the host to cope with the consequences of parasitism and to contain and eventually to overcome parasitism (Coop and Kyriazakis, 2001). Under some co nditions, improved nutritional status may reduce the production losses and mortality rates associated with GIN infections (Sykes and Coop, 2001; Walkden Brown and Kahn, 2002). In a review article, Athanasiadou et al. (2009) stated
46 that host nutrition can a ffect the resident and incoming populations of pathogens and ameliorate the detrimental consequences of an infectious challenge in small ruminants in four different ways: (i) affect the fitness of the parasite through the ingestion of plant compounds, such as plant secondary metabolites; (ii) alter the conditions in the gut environment from beneficial to detrimental and even toxic for parasite survival (iii) positively affect host resistance i.e. the ability of the host to regulate gastrointestinal nematod e establishment development, fecundity and survival and (iv) enhance host resilience to the parasitic infection. Protein supplementation has improved the resilience and resistance of lambs to single and mixed gastrointestinal nematode species infections ( Van Houtert and Sykes, 1996; Knox and Steel, 1996, 1999). Parasitized lambs were better able to resist the effects of infection when given a higher protein diet in early (Laurence et al., 1951; Brunsdon, 1964) and more recent (Abbott et al., 1988; Wallace et al., 1996) studies with sheep. Similarly, positive effects of protein supplementation on resilience to nematode infection have been recorded in goats (van Houtert and Sykes, 1996). Coop and Holmes (1996) noted that the main effect of protein supplementa tion is to increase the rate of acquisition of immunity and increase resistance to reinfection, which has been associated with an enhanced cellular immune response in the gastrointestinal mucosa. They cited recent trials, which showed that growing sheep of fered a free choice between a low and a high protein ration, could modify their diet selection in order to alleviate the increase in protein requirements, which result from GIN infection. In general, the improvements in resilience caused by dietary protein supplementation are greatest in young, naive animals, in which pathophysiological
47 disturbances to the gastrointestinal tract such as protein depleting gastroenteritis and changes in gut function are most pronounced (Holmes, 1993; Fox, 1997). Kambara et a l. (1993) investigated the effect of two levels of dietary protein (110 g CP/kg DM and 200 g CP/kg DM) on the acquisition of immunity in lambs infected with T. colubriformis and showed that dietary protein supplementation increased the resistance of lambs of 2 6 months of age but the effect was not apparent in sheep of 8 12 months of age. Other studies indicated that growing lambs aged 3 6 months acquire immunity to GIN infections more slowly than sheep that are more than 8 months old (Manton et al., 1962; Urquhart et al., 1966 b c ; Dineen et al., 1978). There is compelling evidence (Bown, 1991; Donaldson et al. 1998) that dietary protein is more important than energy at improving resilience, although, if the animal is severely undernourished, increasing e nergy supply will obviously have an effect on resilience. Supplementation with nutrients such as fats that appear to have immunosuppressive properties has also reduced parasite populations in small ruminants (Chandra, 1993). Effects of Condensed Tannins on Nutrient Utilization and Gastrointestinal Nematodes Definition, Classes and Distribution of Tannins in Plants Tannins are anti nutritional phenolic components, which are found in the cell sap of approximately 80% of woody and 15% of herbaceous dicotyled onous species (Bryant et al., 1991). Although tannins are chemically a diverse and ill defined group, they are grouped into two main classes, the hydrolysable (HT) and the condensed tannins (CT) (Mangan, 1988, Athanasiadou et al., 2001). Of the two types, CT are the most common in forage legumes, trees, and shrubs (Barry and McNabb, 1999). They are contained
48 within the vacuoles or cell walls of plant cells and can be expressed in various organs including leaves, stems, bark, roots, flowers or seeds (Barry 1989) depending on plant species. However, tannins are more abundant in the parts of the plant that are most herbivores (Terrill et al., 1992; Van Soest, 1994; lvarez d el Pino et al., 2001). The hydroxyl groups of the carbohydrates in HT are partially or totally esterified with phenolic groups like gallic acid (gallotannins) or ellagic acid (ellagitannins) (Waghorn and McNabb, 2003) and as their name suggests, they can be hydrolyzed by heating with weak acids. Condensed tannins on the other hand, are a group of polyphenolic secondary metabolites synthesized in plants as oligomers or polymers of flavan 3 ol units via the flavonoid pathway (Pereg et al., 1999; Santos Buelg a et al., 2000; Fei et al., 2008). The flavan 3 ol units in CT are linked by carbon carbon bonds (Hagerman and Butler, 1981; Foo et al., 1986; Waghorn and McNabb, 2003) and they are not susceptible to cleavage by hydrolysis (Reed, 1995). The CT are also re ferred to as proanthocyanidins, which is derived from the acid catalyzed oxidation reaction that produces red anthocyanidins through heating of proanthocyanidins in acidic alcohol solutions (Haslam, 1982). Synthesis of CT originates in the cell cytoplasm f rom phenylalanine and acetate precursors (Mueller Harvey and McAllan, 1992) to form catechin units in the cell vacuole. The number of monomeric units are variable (Foo et al., 1996, 1997) thus making an infinite variety of chemical structures possible, whi ch in turn affects the biological properties of the CT (Barry et al., 1999). The constitutive flavan 3 ol monomers in CT have an A, B and C ring structure ( M ueller Harvey and McAllan 1992 ) and the monomeric units are linked together with interflavan bonds
49 predominantly of C8 in the A ring to C4 in the C ring, whereas C4 to C6 linkages that give rise to polymer branching are less common (Haslam, 1989). Condensed Tannin R eactivity with P rotein and O ther M olecules Condensed tannins are known to complex with a range of molecules but derive their main biochemical properties from an ability to precipitate protein at neutral pH (Tanner et al., 2000). The interaction between tannins and protein is very specific (Hagerman and Butter, 1994) and in animals, it starts in the mouth. Condensed tannins are released from the vacuoles of plant cells when chewed (which ruptures plant cells), enabling them to complex with plant proteins, primarily by hydrogen bonding (Loomis and Battaile 1966). The reaction is rapid, with mu ch of the plant protein precipitated by the time it enters the rumen (Mangan et al., 19 76; Min et al. 2003 ) High concentrations of free CT in the rumen can react with other sources of protein such as enzymes secreted by rumen bacteria, and thereby inhibit rumen carbohydrate fermentation (Barry and Manley, 1986). The binding capacity of CT depends on their hydroxylation pattern (Reed 1995), types of terminal groups (Foo et al., 1996), the structure of binding sites (Asquith et al., 1987), and polymer size ( Hagerman and Butler 1981). The reactivity of CT with proteins is based on two mechanisms, hydrogen bonding, which is reversible, and oxidative coupling, which is not reversible (McLeod, 1974, Swain, 1979). The large number of free hydroxyl groups on the numerous phenolic groups in CT enables hydrogen bonding with proteins and other molecules (McLeod, 1974; Hagerman and Butler, 1991; Leinmller et al., 1991). However, the strength of the association appears to be affected by the size of the polymer, the pr edominance of prodelphinidin relative to procyanidin units, the types of terminal groups (2,3 cis or 2,3 trans), and the structure of potential binding sites (C4/C8 or
50 C4/C6 interflavanoid linkages) that affect the shape of the CT polymer chain (Hagerman a nd Butler, 1981; Foo et al., 1996; 1997). The strength of the association is also determined by hydrophobic interactions between the phenol rings and portions of protein or amino acids, the prevailing pH (Asquith and But l er, 1986) and the molecular weight of the CT (Horigome et al., 1988; Haslam, 1989). Formation of tannin protein complexes is specific, both in terms of the tannin and protein involved, and the degree of affinity between the participating molecules (McLeod, 1974; Zucker, 1983; Mangan, 1988; Hagerman and Butler, 1991). The CT protein interaction will be strongest, when the pH is near the isoelectric point of the protein, as this minimizes the protein protein electrostatic repulsion (Hagerman and Butler 1981; Mangan 1988). The CT protein com plexes are stable and insoluble at pH 3.5 7.0, but dissociate and release protein at pH <3.5 (Jones and Mangan, 1977). In contrast, covalently bonded CT protein complexes are thought to be irreversibly bound (Leinmuller et al. 1991) and may not dissociate in the abomasum (McLeod 1974) where the pH is typically about 2. Drying and heating forages can cause CT to bind covalently to other plant constituents, and may reduce the amount of free CT available to bind protein in the rumen (Terrill et al. 1989, 1992 ). Although tannins mainly exert their effects on proteins, they also affect carbohydrates, particularly hemicellulose, cellulose, starch and pectins (Barry and Manley, 1984; Chiquette et al., 1988; Leinmller et al., 1991; Schofield et al., 2001). Conden sed tannins may also complex with glycoproteins, but this is usually with a lower affinity than for protein (Barry 1989). Nutritional Benefits of Condensed Tannins in Ruminants In the ruminant, ingested amino acids are deaminated to release ammonia, whi ch is absorbed across the rumen wall, converted to urea in the liver, and then
51 recycled to the rumen or excreted in the urine (MacRae and Uylatt, 1974; Uylatt and MacRae, 1974; Waghorn and Barry, 1987). Reducing excess ruminal ammonia concentrations is des irable because it minimizes N losses and may prevent reproductive problems in ruminants associated with high levels of PUN (Elrod and Butler 1993; Ferguson et al. 199 3 ). Condensed tannins have been shown to lower soluble protein and ammonia N levels in ru minal fluid (Barry et al. 1986; Chiquette et al. 1989; McMahon et al. 1999) and to promote greater N retention by reducing urea excretion (Egan and Ulyatt ., 1980) and/or by increasing urea recycling to the rumen (Waghorn et al. 1994). Waghorn and McNab b (2003) also reported that dietary CT lowers urinary N excretion and this has potential for reducing nitrous oxide losses and nitrate leaching from dung and urine patches. Condensed tannins also tend to increase the flow of and absorption of non ammonia n itrogen from the small intestine (Min and Hart, 2003). At low dietary concentrations, tannins have been reported to improve utilization of feed protein by ruminants without impairing feed intake or carbohydrate digestibility (Waghorn et al. 1987a; Waghorn 1990; Wang et al. 1994). Barry et al. (2001) reported that moderate levels of CT (20 to 40 g of CT per kg of DM) bind to protein by hydrogen bonding at near neutral pH in the rumen to form CT protein complexes, but dissociate and release bound protein at pH less than 3.5 in the abomasum. Intake of under 50 g CT/kg DM improves the digestive utilization of feed by ruminants mainly because of a reduction in ruminal protein degradation and as a consequence, a greater availability of amino acids for absorption in the small intestine (Schwab, 1995; Barry and McNabb, 1999; Min et al., 2003).
52 Detrimental Effects of Condensed Tannins on Ruminant Nutrition The presence of tannins can affect the palatability and ultimately the amount of forage consumed by animals ( McMahon et al., 1999). An inverse relationship exists between high CT level in forages ( > 50 g CT/kg DM) and their palatability, voluntary intake, digestibility and N retention in ruminants (Kumar and Vaithiyanathan, 1990; Silanikove et al., 1996). Several reports indicate that high concentrations of CT (generally > 50 g per kg of DM) depress voluntary feed intake, digestive efficiency, and animal productivity (Barry and Duncan, 1984; Barry, 1985; Pritchard et al. 1988; Terrill et al. 1989; Reed et al., 199 0; Carulla, 1994; Wiegand et al. 199 6 ; Barahona et al. 1997; Aerts et al., 1999). Similarly, Leinmuller et al. (1991) reported that at concentrations exceeding 6% of dietary DM, CT depress feed intake, reduce the digestibility of fiber and protein, and dec rease the growth rate of ruminant livestock. The intake reduction is attributed to binding of dietary protein, salivary mucoprotein and mucosal epithelial cells by CT (Provenza and Malechek, 1984). This causes a diffused feeling of extreme dryness and a b itter taste in the mouth and throat of the animal commonly referred to as an astringent sensation (Goldstein and Swain, 1963; Mole and Waterman, 1987), prompting the animal to avoid tanniferous feeds (Haslam, 1989). However, Waghorn et al. (1994a) suggeste d that reductions in intake in sheep by CT were more attributable to decreased ruminal turnover and rate of digestion than reductions in palatability in sheep fed pure diets of Lotus pedunculatus in comparison to sheep fed L. pedunculatus with polyethylene glycol, which binds CT and prevents it from binding to proteins. Some studies have shown that fiber degradation in the rumen can be drastically reduced in animals that consume tannin rich feeds (Barry and McNabb, 1999; McSweeney et al., 2001; Hervs et al ., 2003 ). Condensed tannins may reduce cell wall
53 digestibility by binding bacterial enzymes and (or) forming indigestible complexes with cell wall carbohydrates (Barry and Manley, 1984; Barry et al., 1986; Reed et al., 1990). The reduction in digestibility has also been attributed to 1) irreversible binding of dietary protein by tannins, forming a tannin protein complex that resists the effect of digestive enzymes (Mole and Waterman, 1987; Horigome et al., 1988), 2) to binding and thereby inactivating dige stive enzymes (Goldstein and Swain, 1965) 3) to binding both enzymes and substrates (Hagerman and Butler, 1978; Horigome et al., 1988). Tannins can reduce nutrient absorption from the small intestine (Driedger and Ha t field, 1972; Silanikove et al., 1994; McNabb et al., 1998 and Silanikove et al., 2001) due to 1) the presence of tannin protein complexes that failed to dissociate in the abomasum, 2) the formation of tannin digestive enzyme complexes or new tannin dietary protein complexes, or 3) changes in intestinal absorption of nutrients due to the interaction of tannins with intestinal mucosa (Frutos et al., 2004). Though tannin protein complexes can dissociate at pH <3.5 in the abomasum, McNabb et al. (1998) indicated that the pH at the proximal part of the intestine (~5.5) may allow tannin protein complexes to reform, and therefore impede digestion. Condensed tannins are not absorbed into the blood stream (Terrill et al., 1994) but may affect the mucosa of the digestive tract, which could decrease abs orption of other nutrients such as amino acids and in particular methionine and lysine which are most susceptible (Reed, 1995). Decreased methionine availability could increase the toxicity of other plant compounds such as cyanogenic glycosides, because me thionine is involved in the detoxification of cyanide via methylation to thiocyanate (Reed, 1995). Abomasal depolymerization of condensed tannins under acidic conditions may also
54 yield toxic products (McLeod, 1974; Kumar and Singh, 1984; Lindroth and Batzl i, 1984; Mehansho et al., 1987). Ingestion of feeds with high amounts of tannins can cause gastritis and damage to the intestinal mucous membranes, enabling absorption of hydrolyzable tannins (HT) (McLeod, 1974). Such HT can be degraded into toxic end prod ucts that cause hemorrhagic gastroenteritis, liver necrosis, and renal tubular necrosis (Murdiati et al., 1990; Reed, 1995). Differences in Response of Ruminants to Condensed Tannins Effects of CT on ruminants vary with the type of tannin or plant source and the ruminant. Compared to other ruminants, goats are relatively less affected by antinutritional factors in many plants because of differences in their salivary proteins (Foley et al., 1999). Tannins may complex preferentially to the proline rich sali vary proteins, thereby becoming unavailable to interact with and reduce the digestibility of dietary protein (Austin et al. 1989; Hagerman and Robbins 1993). Goats and other browsing animals secrete relatively large quantities of proline rich proteins co nstantly, while sheep only produce them when consuming plants rich in tannins (Robbins et al., 1987; Austin et al., 1989). Gilboa (1995) found that the parotid saliva of goats was relatively rich in proline (6.5%), glutamine (16.5%) and glycine (6.1%), wh ich are known to enhance the affinity of proteins to tannins (Mehansho et al., 1987). Proteins that bind strongly with CT have a high molecular weight, open and flexible structure, and high concentrations of proline and other hydrophobic amino acids (Hager man and Butler, 1981; Asquith and Butler, 1986; Spencer et al., 1988; Waterman, 2000). Some studies indicate that the formation of tannin proline rich protein complexes unlike other protein tannin complexes are stable across the whole pH range of the diges tive tract (Robbins et al., 1987; Austin et al., 1989; McArthur et al., 1995; Narjisse et al., 1995). This would
55 prevent such proteins from being released for postruminal utilization by the acidic conditions in the abomasum. Condensed Tannins as Sustainab le Alternatives to Anthelmintics Several integrated approaches are being investigated as sustainable alternatives to use of anthelmintics to control GIN. These include exploitation of the genetic resistance of livestock, biological control through either v accination or feeding nematophagous fungi that trap free living fecal GIN larvae, manipulation of grazing management, dietary supplementation with protein, or grazing of forages containing tannins (Coop and Kyriazakis, 2001). There are wide variations in t he concentrations of condensed tannins in plants (Mueller Harvey, 1999). Interest in using such plants as an alternative to traditional anthelmintics has stimulated several recent in vivo (Niezen et al., 1995, 1998; Athanasiadou et al., 2000, 2001; Min an d Hart, 2003; Paolini et al., 2003 a, b, c ; Shaik et al., 2004) and in vitro (Athanasiadou et al., 2001; Molan et al., 2002; Bahuaud et al., 2006) studies. Grazing small ruminants on forages high in condensed tannins (CT) has reduced the number of parasite eggs in the feces of sheep and goats (Niezen et al., 1995; Min and Hart, 2003; Paolini et al., 2003a) and hays made from such forages also had anthelmintic effects (Paolini et al., 2003b; Shaik et al., 2004, 2006; Lange et al., 2006). Shaik et al. (2006) r eported a direct inhibitory effect of feeding sericea lespedeza (SL) hay instead of bahiagrass hay on fecal larvae and adult Haemonchus contortus Trichostrongylides circumcincta and T. colubriformis worms in the abomasum and small intestine of goats and a ttributed these responses to direct toxic effects of the condensed tannin in SL. Similarly, Lange et al. (2006) reported that SL hay effectively reduced (67 98%) fecal egg counts (FEC) and worm numbers relative to bermudagrass, with more of an effect on re ducing worm burdens (67.2%)
56 than on reducing establishment of incoming larvae (26.1%). Min et al. (2003b) showed that GIN were controlled when Angora does were grazed on SL (52 g of CT/kg of DM) in spring and summer, but not when goats were grazed on the c ontrol pasture, a mixture of crabgrass (Digitaria Spp.) and tall fescue ( Festuca arundinacea Schreb.; 2.0 g of CT/kg of DM). The SL diet was also associated with a reduction in the numbers of H. contortus (94%) and Teladorsagia spp. (100%) in the abomasum and Trichostrogylus (45%) in the small intestine (Min et al. 2003b). Lambs artificially infected with T. colubriformis had greater daily liveweight gains, lower nematode FEC and lower worm burdens when grazing the perennial Mediterranean legume Hedysarum c oronarium (sulla; ~120 g of CT/kg of DM) than when grazing lucerne ( Medicago sativa L. ), which does not contain CTs (Niezen et al., 1995). Lange et al. (2005) reported reduced FEC and worm counts in sheep fed SL hay compared with bermudagrass hay, and attr ibuted the results to both direct effects of SL on the nematodes and a reduction in fecundity. Condensed tannins control GIN by interfering with hatching of parasite eggs and their development to the infective stage larvae (Min and Hart, 2003). Strong evid ence for direct anthelmintic effects of CTs is provided by an experiment in which drenching sheep infested with Haemonchus contortus Teladorsagia circumcincta and Trichostrongylus vitrinus reduced the viability of infective larvae for all three species (A thanasiadou et al. 2001a). Supporting evidence was provided by Molan et al. (2000) who demonstrated that CT extracted from big trefoil ( Lotus pedunculatus Cav.) birdsfoot trefoil ( Lotus corniculatus L.) Hedysarum coronarium, and sainfoin ( Onobrychis vi ciifolia Scop. ) forages had dose dependent anthelmintic effect against immature stages of several nematode species. They also reduced the rate of larval
57 development by 91%, reduced the number of eggs hatching by 34%, and decreased the mobility of L3 larvae by 30%. Min and Hart ( 2003) reported that in addition to exerting direct effects on internal parasites, CT may indirectly control the parasites by increasing the resistance and resilience of animals to GIN infections through improved protein nutrition. Al though these studies demonstrate the potential of using forage CT to control GIN, Mueller Harvey ( 1999) stated that it is not possible to predict the anti parasitic properties of plant species simply by their CT concentrations because different plants cont ain CTs with very different structures and hence reactivity.
58 CHAPTER 3 EFFECT OF SUPPLEMENT ING BAHIAGRASS HAY W ITH WARM SEASON LEGUME HAYS ON FEED INTAKE, DIGESTIBILITY, NITRO GEN RETENTION, BODY WEIGHT GAIN AND PARASITE BU RDEN OF GOAT KIDS In many parts of the world, the nutritional needs of goats are met using forages alone for economic reasons. Goats eat all classes of forage but prefer about 60% browse, 20% grasses and legumes, and 20% forbs (Pinkerton and Pinkerton, 1996). Hence, most goats are raised on pasture or native range based extensive systems. In Florida as well as the s outhern Coastal Plains of Georgia and Alabama, bahiagrass ( Paspalum notatum Flgge) is the major pasture grass used by the livestock industry (Blount et al., 2001). The yie ld of bahiagrass is normally sufficient to meet intake requirements of most ruminant livestock during the grazing season. However, the quality is often insufficient for growing or lactating ruminants due to low dry matter (DM) digestibility and crude prot ein (CP) concentration (Duble et al., 1971; Johnson et al., 2001; Redmon, 2002). Supplements may be necessary for optimal growth of goats and because protein is usually limiting in grass based diets, protein supplementation usually improves production of goats fed warm season grasses (Ahmed and Nour, 1997; Ott et al., 2002). Grain based commercial supplements may not be economical for growing and finishing meat goats particularly in Florida because most grains are imported into the state at significant co st. Legumes are alternative protein sources to commercial supplements and inter seeded grass legume pastures can be used to extend the grazing season and increase nutrient supply to grazing livestock thereby decreasing feed costs (Leep et al., 2002; Muir, 2002). Gastrointestinal nematode (GIN) parasites are one of the most important disease constraints to small ruminant productivity in the world (Over et al., 1992; Perry et al.,
59 2002). The GIN, particularly Haemonchus contortus present the greatest dange r to the viability of the goat industry in the southeastern region of the United States (Leite Browning, 2006). Control of GIN based on suppressive or therapeutic use of drugs (Coop and Kyriazakis, 2001) has resulted in widespread anthelmintic resistance i n goats, sheep and cattle in many areas of the world (Prichard, 1994; Waller, 1994, 1997) including the southern US (Miller and Craig, 1996; Zajac and Gipson, 2000; Terrill et al., 2001; Mortensen et al., 2003). Therefore, sustainable alternative strategie s are needed to reduce the GIN burden of ruminant livestock. Some recent studies have shown that when fed to goats instead of bahiagrass, sericea lespedeza [ Lespedeza cuneata (Dum. Cours., G. Don ] is an effective dewormer (Lange et al., 2006; Shaik et al. 2006; Moore et al., 2008; Terrill et al., 2009), which also increased the performance of goats (Min et al., 2005 ). However lespedeza is not recommended for Florida because it is not well adapted (Newman et al., 2010). The objective of this study was t o investigate the potential of using warm season legumes adapted to the Florida climate to reduce the parasite burden of goats and enhance their performance. The hypothesis was that supplementing bahiagrass hay with the warm season legume hays will reduce the GIN burden of goats and increase their performance. Materials and Methods Forage P roduction Soybean [SB, Glycine max (L.) Merr. cv. Hinson] and cowpea [CWP, Vigna unguiculata (L.) Walp. cv. Iron clay] were harvested at the University of Florida Santa Fe Beef Unit at the recommended R7 stage (Wiederho lt and Albrecht, 2003; Pederson 2004) and pod yellowing initiation stages (NDA, 1997), respectively, which give the best combination of nutritive value and herbage mass. The R7 stage of SB occurs when 1
60 po d on the main stem has reached its mature color (usually brown or tan color) lower leaves of the plants are beginning to yellow but remain attached to the plant, and seeds at 1 of the 4 uppermost nodes completely fill the pods (Coffey et al., 1995; Sheaff er et al., 2001; Wiederholt and Albrecht, 2003; Pederson, 2004). A 6 wk regrowth of bahiagrass hay (BG, cv. Pensacola) was harvested from an established stand at the same unit. Each forage was mowed and after field drying rolled into 440 kg round bales us ing a Claas Rollant 660 baler (Claas of America, Omah, NE. Square bales (50 kg) of sericea lespedeza [LES, Lespedeza cuneata (Dum. Cours.) G. Don. cv AU Grazer] and perennial peanut (PEA, Arachis glabrata Benth. cv. Florigraze) hay were purchased from prod ucers in North Carolina and Florida respectively. Each hay bale was stored in a fully enclosed barn for up to 5 months and fed without grinding. Animals All animal procedures were approved by the University of Florida Institutional Animal Care and Use C ommittee. The experiment was conducted at the Department of Animal Sciences, University of Florida, Gainesville, FL from May to September 2011. The average temperature, relative humidity, and precipitation during the experiment were 78.4 + 4 o C, 78.7 + 8 % and 9.6 + 26.4 mm respectively (FAWN, 2012). The exper iment had three phases of implementation namely digestibility, infection and performance. Boer Spanish Kiko cross goats (n= 40) weighing 24.3 9.8 kg were orally dewormed with Albendazole (Valbaz en, 10 mg/kg BW) and Moxidectin (Cydectin, 0.4 mg/kg BW), weighed for two consecutive days, stratified by body weight, and allocated to 5 blocks such that within each block live weights did not differ by more than 5 kg. Goats in each block were then random ly assigned to 5 dietary treatments namely BG
61 hay alone and 50:50 (DM basis) mixtures of BG hay and SB, CWP, PEA, or LES hay. Legume supplemented diets were formulated to meet or exceed the nutrient requirements of a 25 kg Boer goat gaining 25 g/d (NRC, 2 007). Housing and feeding G oats were first housed individually in metabolic crates (100 x 40 x 80 cm). Diets were fed for an adaptation period of 17 days (d) after which measurements of feed consumed, total feces and urine produced and feed refused were t aken daily during a 7 d period. Canvas fecal bags were strapped onto each goat for feces collection and contents were weighed twice daily. Urine was collected twice daily from 35 goats ( 7 per treatment), which were in cages adapted for urine collection. Th e bahiagrass and respective legume supplements were hand mixed and offered at 0700 and 1400 h daily at an ad libitum level. To achieve the 50:50 mix, the projected total diet amount to be offered for a certain day was calculated and half was fed as either bahiagrass or the legume. Water was also provided for ad libitum intake and 20 g of a vitamin mineral premix (Sweetlix Minerals Livestock Supplement System, Mankato, MN) was added to the diet of each goat daily. The mineral vitamin mix contained at least 1 4% Ca, 8% P, 10% NaCl, 1.5% Mg, 1.5% K, 1.55% S, 1.25% Fe, 1.26% Mn, 1.25% Zn, 240 mg/kg Co, 1750 mg/kg Cu, 1,810 mg/kg 450 mg/kg I, 50 mg/kg Se, 136 100 IU/kg Vitamin A, 22 680 lU/ kg Vitamin D3 and 182 lU/ kg Vitamin E. Goats were removed from the cages and exercised for 1 h every 7 d. On day 24, g oats were removed from the cages, weighed and then placed on bahiagrass pasture for 42 days ( June 22 August 5, 2011 ) to allow natural infection with Haemonchus contortus L3 larvae and coccidian oocysts, whic h are prevalent in the pasture in the summer. On d ay 66 (August 5, 2011) goats were weighed blood
62 sampled by jugular venipuncture and then housed in 20 m 2 pens (3 pens per treatment, 2 3 goats per pen) with concrete floors and feed and water troughs and fed the same diets until d 105. Sample collection Feed offered and orts were weighed daily during the 7 day measurement period and representatively sampled for chemical analysis. A 20% subsample of the fecal output from each goat was refrigerated (4C) for subsequent analysis. The volume of urine produced was measured twice daily and sulfuric acid was added to subsamples prior to freezing ( 20 o C) to ensure that the pH remained below 2.0. Feces and urine samples from the measurement period were composited by goat and analyzed for N concentration. In addition, concentrations of organic matter (OM) and neutral detergent fiber (NDF) were determined i n the feces. Intake and apparent in vivo digestibility of DM, OM, N and NDF, and N retention were calculated. Goats were weighed on d 0 and 24 and about 20 mL of whole blood was sampled by jugular venipuncture into vacutainer tubes (BD, Franklin Lakes, NJ) containing sodium heparin anticoagulant. The blood was centrifuged at 1920 x g for 20 minutes at 4 o C to separ ate the plasma, which was stored at 20 o C for further analysis. Ruminal fluid was collected from 20 randomly selected goats (4 per treatment) on d 22 by aspiration from orally inserted stomach tubes 4 h after the morning feeding. The rumen contents were fi ltered through two layers of cheesecloth and the pH was measured (Accumet, model XL 25, Fischer Scientific, Pittsburg, PA) immediately. Approximately 0.1 ml 50% H 2 SO 4 was added to the ruminal fluid to reduce the pH to < 2. After the reaction with bicarbo nate subsided, samples were centrifuged for 30 min at 4 o C and 2795 g, and frozen ( 20 o C) for subsequent analysis.
63 In pens, o rts were collected and weighed once weekly and representative samples of each feed, orts, jugular blood, and feces were taken week ly and stored for further analysis. Approximately 3 mL of blood plasma were col lected, processed, and stored as described in Fecal samples (approximately 4 g), were collected directly from the rectum and immediately analyzed for gastrointestinal nematode (GIN) and Eimeria spp. fecal egg counts (FEC). Body weights were measured at the beginning and end of the experiment and weekly in the intervening period. Goats were monitored weekly for evidence of parasite infection using the FAMACHA eye chart (Van Wyk and Bath, 2002), which is a color coded chart showing five pictures of the conjunctiva of goat eyelids numbered from 1 (normal red color) to 5 (very pale color denoting severe anemia). Goats with packed cell volume values (PCV) below 19% were closely moni tored for further decreases in PCV during the subsequent days and dewormed as needed. Those with PCV below 15 were euthanized. Chemical analysis Samples of feed offered, orts and feces were oven dried at 60 o C for 48 h to determine DM concentration and gr ound to pass through a 1 mm screen in a Willey mill (Arthur H. Thomas Company, Philadelphia, PA). Residual DM of ground samples was determined by oven drying at 105C overnight, ash was measured by combustion in a muffle furnace at 600C overnight. Total N was determined by rapid combustion using a macro elemental N analyzer (Elementar, vario MAX CN, Elementar Americas, Mount Laurel, NJ) and used to calculate CP (N x 6.25). Neutral detergent fiber (NDF) was analyzed using the method of Van Soest et al. (199 1). Amylase and sodium sulfite were used for NDF analysis and the results were expressed exclusive of residual ash. Feed samples were analyzed for acid detergent fiber (ADF) and acid detergent lignin (ADL)
64 using the method of AOAC (1990). Condensed tannin (CT) concentration of the hays was determined as described by Terrill et al. (1992). Condensed tannin extracted from each species was used to develop the respective standard curve analyzing the tannin concentration of that species (Wolfe et al., 2008). Ur ine was analyzed using the Kjeldahl technique at Dairy One analytical laboratory, Ithaca, NY. Volatile fatty acids (VFA) in ruminal fluid were measured using the method of Canale et al. (1984) via a high pressure liquid chromatograph system (Hi tachi, FL 7485, Tokyo, Japan) coupled to a UV detector (Spectroflow 757, ABI Analytical Kratos Division, Ramsey, NJ) set at 210 nm. The column was a Bio Rad Aminex HPX 87H (Bio Rad laboratories, Hercules, CA) with 0.015 M H 2 SO 4 mobile phase and a flow rate of 0.7 mL /min at 45 o C. Ruminal fluid NH 3 N concentration was determined by an ALPKEM auto analyzer (ALPKEM Corporation, Clackamas, OR) with an adaptation of the Noel and Hambleton (1976) procedure that involved c o lorimetric quantification of N. Plasma urea N (PUN ), glucose (Pglu) concentration were measured using adaptations for a Technicon Autoanalyzer II (Bran Luebbe, Elinsford, NY) of methods of Coulombe and Favreau (1963) and Gochman and Schmitz (1972), respectively. Blood samples were analyzed for p acked cell volume (PCV) was measured using a micro hematocrit reader (Cat. #2201, Damon/IEC Division, Needham Heights, MA) after centrifugation in a micro hematocrit centrifuge (Model IEC MB Damon/IEC Division, Needham Heights, MA). Plasma haptoglobin concentratio ns were determined by measuring haptoglobin/hemoglobin complexing based on differences in peroxidase activit y (Makimura and Suzuki, 1982).
65 F ecal samples were used to enumerate FEC of H. contortus and Eimeria spp. using the modified McMaster procedure of W hitlock (1948). Statistical Analysis Data from the digestibility phase were analyzed as a randomized complete block design with 5 treatments and eight goats (experimental units) per treatment. The model for analyzing the animal data included treatment, bl ock and goat effects. The GLIMMIX procedure of SAS (SAS v 9.3; 2012, SAS Inst., Inc., Cary, NC) was used for the analysis and least square means were separated with the Tukey procedure when the overall treatment effect was significant (P<0.05). Tendencies were declared when the P value was > 0.05 < 0.11. Data from the performance phase were analyzed as a randomized complete block design with 5 treatments and 3 experimental units (pens) per treatment using the GLIMMIX procedure. The model for analyzing trea tment effects included treatment, block, time (repeated measure), treatment x time and pen(treatment). The covariance structure with the least Akaike information criterion was chosen for each analysis performed. The slice command was used to detect differe nces between treatments at specific time points. For FEC data, the distribution of residuals was examined using the normal probability, quantiles quantiles and predicted mean plots and data were log transformed if appropriate. Mortality rates were analyze d using the LOGISTIC procedure and the EXACT statement with a model that included the observed outcome, treatment, block, and pen effects Least square means were separated with the Tukey
66 Results and Discussion Forage chemical composition Table 3 1 shows the chemical composition of the forages used in the study. All supplemental legumes had greater CP and ADL concentrations than BG. Among the legumes, SOY had greater CP concentration than PEA and CWP and LES had the greatest lignin concentration. The BG had the greatest NDF concentration, followed by LES. Cowpea had greater ADF concentration than other hays. Condensed tannin concentrations were greater in LES than PEA but they were not detected in the other forages. The CP concentrations in this study were similar to those for BG and SOY in the study of Foster et al. (2009) but lower than those for CWP and PEA, whereas NDF concentrations were greater for BG, CWP and PEA in this study. Organic matter, CP and NDF concentrations for BG were lower than those reported by Kostenbauder et al. (2007). The NDF and ADF concentrations of LES were similar while the CP concentration was greater than th at reported by Turner et al. (20 05). These differences may be attributable to differences in cultivar maturity at harvest and growth environment s of the forages. Sericea lespedeza had more CT than the other forages but the concentration was not high enough (>50 g/kg DM) to decrease fe ed intake, digestive efficiency and animal producti on (Reed et al., 1990; Carulla, 1994; Wiegand et al. 199 6 ; Barahona et al. 1997; Aerts et al., 1999). At these relatively low dietary concentrations, tannins would be expected to improve utilization of f eed protein by ruminants without impairing feed intake or carbohydrate digestibility (Waghorn et al. 1987; Waghorn 1990; Wang et al. 1994).
67 Intake, digestibility and nitrogen retention Intake of DM (DMI), OM (OMI), NDF (NDFI) and CP (CPI) is presented in Table 3 2. Daily DMI ( g/d) tended (P = 0.07) to increase with LES and PEA supplementation as did OMI and NDFI (P = 0.06 and 0.09, respectively). Crude protein intake was greater (P = 0.01) in goats fed LES and PEA than other forages. Generally, DMI w as at the lower end of the typical range (1.8 to 3.8%) for meat goats (Devendra and Burns, 1983). This could have been due to the relatively high NDF concentrations of the forages and loss of leaves during haymaking, which can reduce DMI particularly in le gumes (Linn and Martin, 199 9). Another reason for the low DMI could be the long particle size of the hays. Omokanye et al. (200 1 ) noted that chopping of forage browse s before feeding sheep improved feed intake by 60%. Intake in this study w as lower than f or the chopped forages fed to sheep by Foster et al. (2009). In this study, the forages were intentionally not chopped to prevent leaf loss and the attendant decreases in nutritive value and because most goat producers do not chop hay before it is fed Ho wever, this may have facilitated selection for more nutritious parts of the forage and reduced intake by goats, which are inherently very selective feeders (Morand Fehr et al., 1991). The DMI for PEA and LES were similar to those reported by Ravhuhali e t al. (2011) and tended to be greater than that for BG. In contrast, DMI tended to be less among goats fed CWP and SOY rather than BG. This is largely attributable to the thicker stems of CWP and SOY, which would have increased selection by goats. The broa d leaves of CWP and SOY would have also been more prone to shatter during haymaking and sampling than those of the other hays further reducing the amount of CP and highly nutritious components available for consumption on these forages.
68 The in vivo appare nt DMD of the BG in this study (Table 3 3) was similar to th at ( 57.3% ) reported by Kostenbauder et al. (2007) and DMD values for the other hays were similar to or slightly lower than those reported in other studies (Njarui et al., 2003; Foster et al., 2009 ; Ravhuhali et al., 2011). The DMD and OMD of the hays were not affected (P = 0.42 and 0.58, respectively) by legume supplementation. These results contradict others, which indicated that supplementing poor quality basal grass diets with legume forage incr eased DMD (Getachew et al., 1994; Foster et al., 2009) even though a similar numerical trend was consistently evident in this study. Statistically significant differences (P<0.05) may have not been achieved in this study due to the high lignin concentratio ns of the legumes which would limit digestibility and their relatively low DMI and CP concentrations, which would have limited supply of sufficient N to the rumen to increase microbial digestion of the forages. As in the study of Foster et al. (2009), le gume supplementation did not increase NDF digestibility because legumes contained more lignin than BG. However, legume supplementation increased (P = 0.01) CP digestibility as reported in other studies (Alokan, 2004; Foster et al., 2009). There was a ten dency (P = 0.06) for increased N intake with LES and PEA supplementation (Table 3 4) but fecal and urinary N output were unaffected (P > 0.10) by treatment. Consequently, LES and PEA supplementation increased (P = 0.03) N retention relative to BG but feedi ng CWP and SOY did not. In addition to the greater CPI of LES and PEA, the increased N retention of animals fed these diets is likely attributable at least partly to the CT they contained, which promote greater N retention
69 by reducing urea excretion and or by increasing urea recycling to the rumen (Waghorn et al. 1994). Ruminal fermentation indices and blood metabolites Table 3 5 summarizes the effects of supplementing BG hay with LES, CWP, SOY and PEA hays on ruminal fermentation indices and PUN and Pglu concentrations. The ruminal pH values in this study were within the normal range of 6.2 to 6.8 for forage based diets (Ishler and Heinrichs, 1996) and they were unaffected by treatment. There was a tendency (P = 0.08) for increased ammonia N concentration with legume supplementation. However, values did not proportionately reflect N intake values perhaps reflecting differences in N recycling on the diets. Most values approximated that (5 mg/dL) reported to optimize ruminal microbial protein synthesis in vi tro (Satter and Slyter, 1974) Broderick (2007) suggested that greater ammonia N concentrations are required in situ and in vivo than the 5 mg/dL reported by Satter and Slyter (1974). Values for the control and legume supplemented diets approximated and were lower than corresponding respective values reported by ( Foster et al. 2009 ). Lower values for the legume diets in this study may reflect the lower N intake. Total VFA concentration was lower (P = 0.04) in goats fed LES than those fed BG, and goats fe d LES had the lowest ruminal ammonia N concentrations among legume supplemented diets. These factors may be due to binding of dietary carbohydrate and CP fractions by the CT in LES. Nevertheless, because the concentration of CT in LES was low (<5%), such bonds are likely to have been broken in the abomasum (Barry et al., 2001). It must be noted however that the values for concentrations o n this study were within the normal range (100 t0 120 mM/L) characteristic of forage fed ruminants (Bergm an, 1990) were similar for BG, CWP and
70 PEA but lower for SOY than those reported by Foster et al. (2009) and higher for BG, PEA but lower for LES than reported by Zarate, 2012 Concentrations of individual VFA, the acetate to pro pionate ratio, and PUN and Pglu concentrations were not affected by treatment but PUN and Pglu concentrations were within the normal ranges (8 to 20 and 50 to 80 mg/dL; Kenako, 1989) and they approximated those reported by Foster et al. (2009) and Zarate ( 2012). Hammond, (1997) reported that increased solubility or degradability of dietary protein leads to increased r uminal ammonia N concentrations and a corresponding increase in the concentration of P UN However, despite their high rumen degradable prote in concentrations and their tendency to increase rumen ammonia concentration, legume supplementation did not affect PUN concentration. Parasite burden All the animals in the Control treatment had been dewormed by d 35 due to low PCV consequently the dat a reported is from the first 28 d of the experiment. Supplementing BG with LES reduced (P = 0.01) the FEC of GIN (Table 3 6) the majority of which are eggs of H. contortus since this worm usually accounts for 75 to 100% of the total fecal nematode egg ou tput (Mortensen et al., 2003). This result agrees with the report of Terrill et al. (2009), which stated inclusion of LES at 50% of diet DM is effective at reducing FEC in goats and possibly reducing pasture infection with GIN larvae. Similarly, Lange et a l. (2006) reported that LES was as effective or better at reducing FEC in sheep and eliminating established adult worm burdens than an anthelmintic treatment when resistance is present. In this study, LES hay reduced GIN FEC by 58.6%, which was less than t he 67 98% FEC reduction reported by Lange et al. (2006) when BG hay was replaced completely by LES hay.
71 Terrill et al. (2009) stated that although feeding SL at 50% of the diet would be beneficial for possible reduction of pasture infection with GIN larv ae, a higher level (>50%) of inclusion of dried LES is needed to kill adult worms. In contrast, in a complementary study to this one at the University of Florida, Zarate (2012), a diet containing 50% of LES and 50% of BG reduced the population of adult GIN worms in the abomasum by 52%. Adult worms were not enumerated in this study because all goats on the BG diet had been dewormed by d 35 due to low PCV values. It was interesting to note that though GIN FEC values for SOY and PEA did not differ (P>0.05) f rom those of BG or LES, they tended (P = 0.06 and 0.11) to be less than those of BG. Therefore, feeding SOY or LES tended (P < 0.1) to reduce GIN FEC by 31.0 and 25.3%, respectively. In a complementary study, Zarate (2012) reported that PEA supplementation reduced GIN adult worms in goats by 42% but SOY was not included in the study. The results in this and the complementary study are perhaps the first indications that feeding SOY and PEA can reduce the parasite burden of small ruminants. Parasite inhibitin g secondary metabolites are not known to occur in high concentrations in these forages, therefore their inhibitory effects on the parasites are likely attributable to the enhanced immune response resulting from the increased nutritional status of goats fed these diets. Supplementing BG with LES tended (P = 0.08) to reduce Eimeria FEC relative to feeding BG alone, perhaps reflecting the inhibitory action of the tannins in LES. In contrast, and for unknown reasons, supplementation with CWP tended to increas e the counts.
72 Indices of anemia and the immune response Supplementation with SB and PEA increased (P = 0.01) the PCV relative to fee d ing BG alone (Table 3 6 ). A similar trend (P = 0.09) was evident for LES but that for CWP was only numerical (P = 0.19). It is estimated that each GIN worm sucks about 0.05 ml of blood per day by ingestion and causes seepage from lesions (Urquhart et al. 2000; Waller and Chandrawathani, 2005) thereby accounting for lower PCV values in parasitized ruminants. In this study, SO Y, LES, and PEA increased the PCV reflecting their inhibitory effects on anemia causing GIN. These responses could be attributed to beneficial effects of supplementation on the immune response of the goats. Bown et al. (1991) reported that protein supplem entation is effective at enhancing specific immune responses for intestinal parasite infection. Nutrition affects the ability of the host to cope with the consequences of parasitism and to contain and eventually overcome parasitism (Coop and Kyriazakis, 20 01). All legumes tended (P = 0.08) to increase FAMACHA scores. The FAMACHA chart is an alternative to PCV measurements that allows for frequent, cheap and easy monitoring of the worm infection status of animals in order to decide which animals require se lective treatment (Bath et al., 2001). van Wyk and Bath (2002) reported that during the course of fatal haemonchosis, the color of the conjunctivae of ruminants changes from the deep red of healthy ruminant, through shades of pink to practically white, as a result of a progressively worsening anemia. The FAMACHA results demonstrate that legume supplementation reduced anemia in goats, thus confirming packed cell volume results. Likewise, legume supplementation reduced (P = 0.001) haptoglobin concentrations but the effects differed with time (P < 0.001; Figure 3 1 ). Haptoglobin concentrations increased over time and were persistently greater than
73 those of all treatments except CWP from weeks 2 4 This reflects the inflammatory stress resulting from GIN parasi tism, which required a heightened immune defense response. In contrast, the haptoglobin concentrations in goats fed SB, PEA, and LES were lower than those of goats fed BG though LES consistently had the lowest values. The lower haptoglobin concentrations r eflect lower inflammatory stress response due to the lower level of GIN parasitism in goats fed SB, PEA, and LES Sericea Lespedeza probably had the least haptoglobin concentrations because of the inhibitory effect of the CT it contained on GIN larvae deve lopment and adult worm survival (Shaik et al., 2006). Animal performance and indices of resilience Table 3 7 shows the effects of supplementing BG hay with the legumes on the performance of goats. Supplementation with SB, PEA and LES increased (P < 0.01) DMI expressed as g/head/day or % of BW. Lespedeza and PEA had the greatest DMI whereas CWP had the least among the supplemental legumes, perhaps due to the thick stems and high ADF concentration of CWP. Dry matter intake for goats fed LES and PEA were si milar to the 3.0 3.4% of body weight recommended for a 25 kg goat (NRC, 2007; Mamoon, 2008) and those for all forages were greater than values in digestibility phase This may have been because animals were more accustomed to being handled in the perform ance phase of the study (pen feeding) and the stress of being fitted with a fecal bag and housed individually in a metabolism crate was absent. G oats fed SOY and LES gained more BW than the expected 25 g/ head/ d, and those fed CWP and PEA gained less for reasons that are not clear. Legume supplementation did not result in a statistically greater ADG relative to that of goats fed BG This may be due to the short duration of the monitoring period. In addition, the
74 beneficial effects of legume supplementati on on performance may have been masked by the low levels of parasitic infection. Coop et al. (1995) suggested that the reduced animal performance in parasitized ruminants is due to competing demands for available nutrients between growth, repair of gastroi ntestinal pathology, and the immune response. Hoste (2001) reported that the pathophysiological effects of parasite infections include loss of appetite, intestinal motility and flow alterations, such as increased gastric pH, and impaired energy and protein metabolism. Table 3 8 shows the effects of dietary treatments on indices of resilience to parasitism during the entire 49 d study. It took longer for the PCV of goats fed LES, PEA, and SB to drop to 19 and 15% than for goats fed CWP and BG. In additio n, 62.5% (5/8) of goats were euthanized due to low PCV (15%) in the BG and CWP treatments, whereas 32.5% (3/8), 12.5% (1/8) and 0% (0/8) were euthanized in the SB, PEA, and LES treatments, respectively. Therefore, th e s e data support the other results of t he study indicating that resilience to parasitism was increased by feeding SB, PEA and LES but not CWP. That no goats were euthanized on the LES diet confirms that it was the most effective dewormer. The deworming efficacy of LES has been shown in several other studies (Lange et al., 2006; Terrill et al., 2009), but this is perhaps the first study indicating that SB and PEA may also increase the resilience of goats to GIN.
75 CHAPTER 4 CONCLUSIONS All over the world, m ost goats are raised on pastur e or native range based extensive systems for economic reasons. Bahiagrass ( Paspalum notatum Flgge) is the major pasture grass used by the livestock industry in Florida as well as the southern Coastal Plains of Georgia and Alabama (Blount et al., 2001) The yield of bahiagrass is normally sufficient to meet intake requirements of most ruminant livestock during the grazing season. However, the quality is often insufficient for growing or lactating ruminants due to low dry matter (DM) digestibility and c rude protein (CP) concentration (Duble et al., 1971; Johnson et al., 2001; Redmon, 2002). As such, supplements may be necessary for optimal growth of goats, and because protein is usually limiting in grass based diets, protein supplementation usually impro ves production of goats fed warm season grasses (Ahmed and Nour, 1997; Ott et al., 2002). Gastrointestinal nematodes (GIN), particularly Haemonchus contortus are one of the most important disease constraints to small ruminant productivity in the world (O ver et al., 1992; Perry et al., 2002) and they present the greatest danger to the viability of the goat industry in the southeastern region of the United States (Leite Browning, 2006). Control of GIN based on suppressive or therapeutic use of drugs (Coop a nd Kyriazakis, 2001) has resulted in widespread anthelmintic resistance in goats, sheep and cattle in many areas of the world (Prichard, 1994; Waller, 1994, 1997; Pomroy et al., 2002) including the southern US (Miller and Craig, 1996; Zajac and Gipson, 200 0; Terrill et al., 2001; Mortensen et al., 2003). Therefore, sustainable alternative strategies are needed to reduce the GIN burden of ruminant livestock. This study sought to investigate the potential of using warm season legumes adapted to Florida to re duce the parasite
76 burden of goats and enhance their performance. In phase 1, the study determined the effects of supplementing bahiagrass ( Paspalum notatum Flgge; BG) hay with hays of perennial peanut ( Arachis glabrata Benth.) (PEA), soybean [ Glycine max (L.) Merr.] (SOY), cowpea [ Vigna unguiculata (L.) Walp.] (CWP), or sericea lespedeza ( Lespedeza cuneata Dum. Cuors. G. don) (LEA] on feed intake, digestibility, and nitrogen (N) retention. A further objective examined the effects of the same diets on growt h performance, immune response and parasite burden in goats. Forty Boer Spanish Kiko goats weighing 24.3 9.8 kg were orally dewormed with Albendazole (Valbazen, 10 mg/kg BW) and Moxidectin (Cydectin, 0.4 mg/kg BW), stratified by body weight and rando mly assigned to diets of bahiagrass hay alone or supplemented (50% of diet dry matter) with LES, PEA, CWP or SOY hay. Diets were fed for ad libitum consumption for 16 days of adaptation and 7 days of measurement of feed intake and feces and urine output. G oats were then naturally infected with Haemonchus contortus L3 larvae and Eimeria spp. oocytes by grazing bahiagrass pasture infested with gastrointestinal nematodes (GIN) for 42 days. Subsequently, goats were housed in 20 m 2 pens (3 pens per treatment, 2 3 goats per pen) and fed the phase 1 diets for 49 days. Representative samples of each feed, orts, jugular blood, and feces were taken weekly and stored for further analysis. Body weights were measured at the beginning and end of the experiment and weekly in the intervening period. Goats were monitored weekly for evidence of parasite infection using the FAMACHA eye chart (Van Wyk and Bath, 2002) and by monitoring blood packed cell volume and haptoglobin concentrations and fecal egg counts of trichostrongyle s and Eimeria spp.
77 I ntakes of DM, OM, NDF and CP were only increased by supplementation with LES and PEA. All legumes increased or tended to increase N digestibility and ruminal ammonia N concentration. However, N retention was only increased by suppleme ntation with LES and PEA. S upplementation with PEA, LES and SB increased or tended to increase PCV, decreased FAMACHA scores and prevented the parasitism induced increase in the immune response due to feeding BG or CWP. Feeding LES reduced FEC of GIN and f eeding PEA and SB had the same tendency. Feeding LES, PEA and SB increased DMI compared to BG but did not increase ADG. Perennial peanut and SB are promising supplements for increasing the resilience of goats to GIN parasites but LES was the most effectiv e treatment. To enhance understanding of the feeding behavior and growth performance of goats as influenced by legume supplementation, further research is required to: 1) separately quantify the amounts of legume and basal diet consumed by goats in order to quantify the DMI and energy and protein supply from the basal and supplemental dietary components, 2) determine effects of processing (chopping) grass and legume hays on intake and digestion 3) quantify legume supplementation effects on the number, via bility, and identity of infective larvae and adult GIN worms, and 4) examine effects of substituting BG hay with each legume on parasite burden and animal performance, 5) elucidate the mechanisms by which SB and PEA reduced the FEC of GIN in the goats.
78 Table 3 1 Chemical C omposition of T he B ahiagrass, P erennial P eanut, S ericea L espedeza, C owpea and S oybean H ays Component Bahiagrass Cowpea Soybean Peanut Lespedeza SEM DM,% 89.8 88.5 89.1 89.3 90.5 0.004 Ash, % of DM 8.5 8.5 7.9 7.9 8.6 0.07 OM,% of D M 91.6 91.5 92.1 92.1 91.4 0.1 CP,% of DM 7.9 10.7 13.5 12.5 13.1 0.25 NDF,% of DM 76.6 60.9 58.3 45.8 61.1 0.5 ADF,% of DM 37.4 46.3 40.8 32.2 43.4 0.5 ADL,% of DM 3.46 10 9.7 9 16 0.17 Condensed tannins, % of DM ND ND ND 0.5 3.9 0.16 ND = not dete cted. Table 3 2 Effects of S upplementing B ahiagrass (BG) H ay with P erennial P eanut (PEA), S ericea L espedeza (LES), C owpea (CWP) and S oybean (SB) H ays on I ntake of D ry M atter (DMI), O rganic M atter (OMI), N eutral D etergent F iber (NDFI), and N itrogen (NI) BG CWP SB PEA LES SEM P value DMI, g 297 241 252 384 394 25.9 0.07 OMI, g 291 224 229 367 360 50.3 0.06 NDFI, g 253 177 174 259 278 41.1 0.09 CPI, g 24.9 b 22.8 b 26.6 b 40.8 a 41.2 a 5.6 0.01 a, b, c Means within a row with different superscripts differ (P < 0.05)
79 Table 3 3 Effects of S upplementing B ahiagrass (BG) H ay with P erennial P eanut (PEA), S ericea L espedeza (LES), C owpea (CWP) and S oybean (SB) H ays on D igestibility of D ry M atter (DMD), O rganic M atter (OMD), N eutral D etergent F iber (NDFD) and N itr ogen (ND) BG CWP SB PEA LES SEM P value DMD, % 55.1 60.6 57.2 60.5 59.3 3.09 0.42 OMD, % 55.6 60.1 57 61.1 61 3.43 0.58 NDFD, % 61.6 63.6 58.12 60.07 60.3 3.26 0.72 ND, % 40.8 b 53.6 a 55.5 a 58.9 a 55.6 a 4 0.01 a, b, c Means within a row with differe nt superscripts differ (P < 0.05) Table 3 4 Effects of S upplementing B ahiagrass (BG) H ay with P erennial P eanut (PEA), S ericea L espedeza (LES), C owpea (CWP) and S oybean (SB) H ays on N itrogen (N) B alance BG CWP SB PEA LES SEM P value N intake g/d 3.66 3 .66 4.32 6.17 6.34 0.99 0.06 Fecal N output, g/d 2.13 1.68 1.7 2.29 2.71 0.44 0.2 Urinary N output, g/d 0.75 0.93 0.87 0.56 0.38 0.25 0.45 Retained N, g/d 0.14 b 1.19 b 1.12 b 2.30 ab 2.84 a 0.64 0.03 a b, c Means within a row with different superscripts differ (P < 0.05)
80 Table 3 5 Effects of S upplementing B ahiagrass (BG) H ay with P erennial P eanut (PEA), S ericea L espedeza (LES), C owpea (CWP) and S oybean (SB) H ays on R uminal F ermentation I ndices and B lood U rea N itrogen (BUN) and P lasma G lucose (PGlu) C on centrations of G oats BG CWP SB PEA LES SEM P value Ruminal pH 6.44 6.39 6.60 6.34 6.59 0.20 0.72 Ammonia N, mg/L 34.3 51.1 49.7 40.3 35.8 5.61 0.08 Total VFA mM 115 ab 101 bc 96.4 bc 127 a 85.8 c 10.0 0.04 Acetate, mmol/100 mmol 72.0 72.5 72.0 73.9 78. 3 2.93 0.47 Propionate, mmol/100 mmol 22.0 20.4 19.8 20.3 17.0 1.83 0.35 Butyrate mmol/100 mmol 5.41 5.91 6.93 6.15 2.48 1.23 0.13 Acetate:propionate 3.30 3.58 3.78 3.69 4.62 0.46 0.30 BUN, mg/dL 11.3 10.5 12.8 12.0 12.3 1.01 0.52 PGlu, mg/dL 71.5 63 .9 67.4 68.0 69.3 4.03 0.70 a, b, c Means within a row with different superscripts differ ( P < 0.05)
81 Table 3 6 Effects of S upplementing B ahiagrass (BG) H ay with P erennial P eanut (PEA), S ericea L espedeza (LES), C owpea (CWP) and S oybean (SB) H ays on G a strointestinal (GIN), Eimeria sp. (EIM) F ecal E gg C ounts (FEC) P acked C ell V olume, FAMACHA S cores and H aptoglobin C oncentration of G oats P value BG CWP SB PEA LES SEM Trt 1 Week Trt x week GIN FEC, eggs/g 2773 a 2640 a 1914 ab* 2072 ab** 114 7 b 284 0.01 0.24 0.14 EIM FEC, eggs/g 1923 2700 2197 2162 1246 362 0.08 <0.01 0.11 Packed cell volume, % 21.5 b 26.4 ab 30.1 a 29.6 a 27.5 ab 1.59 0.01 <0.001 0.67 FAMACHA scores 2.29 1.86 1.66 1.53 1.78 0.18 0.08 <0.001 0.19 Haptoglobin, arbitrary units (x 100) 5.83 a 4.68 b 3.45 dc 3.87 c 2.99 d 0.15 <0.001 <0.001 <0.001 a, b, c Means within a row with different superscripts differ (P < 0.05) Differed from BG (P = 0.06) ** Differed from BG ( P = 0.11) 1 Treatment.
82 Table 3 7 Effects of S uppleme nting B ahiagrass (BG) H ay with P erennial P eanut (PEA), S ericea L espedeza (LES), C owpea (CWP) and S oybean (SB) H ays on T he P erformance of G oats P values BG CWP SB PEA LES SEM Trt 1 week Trt x week DMI, g /d 426 d 562 cd 630 bc 803 ab 863 a 79 < 0.01 0.02 0.06 DMI as % of 2.26 b 2.27 b 3.02 a 3.22 a 3.37 a 0.16 <0.01 0.58 0.83 BW 2 Initial BW, kg 24.9 24.4 23.5 25.1 24.7 3.34 1 NA NA Final BW, kg 25 24.1 24.5 25.6 26.2 3.75 1 NA NA ADG 3 g/day 4.46 9.12 35.2 15.4 51.6 22.2 0.37 NA NA a, b Means within a row with different superscripts differ (P < 0.05) 1 Treatment 2 BW = body weight 3 ADG = average daily gain.
83 Table 3 8 Effects of S upplementing B ahiagrass (BG) H ay with P erennial P eanut (PEA), S ericea L espedeza (LES), C owpea (CWP ) and S oybean (SB) H ays on I ndices of R esilience of G oats to P arasitism BG CWP SB PEA LES SEM P value Days to PCV 1 <19% 21.1 b 31.2 ab 37.7 a 42.1 a 38.6 a 4.09 0.005 Days to PCV < 15% 29.7 c 32.3 bc 41.1 ab 42.0 ab 47.2 a 4.09 0.005 % Euthanized 62.5 62.5 37 .5 12.5 0 0.018 1 Packed cell volume
84 Figure 3 1 Effects of Supplementing Bahiagrass (BG) Hay with Perennial Peanut (PEA), Sericea Lespedeza (LES), Cowpea (CWP) and Soybean (SB) Hays on Haptoglobin Concentrations Means at the Week ndicated differed (P < 0.05). Error bars are standard errors *
85 LIST OF REFERENCES Abbot, E. E., J. J. Parkins, and P. H. Holmes. 1988. Influence of dietary protein on the pathophysiology of haemonchosis in lambs given continuous infections. Res. Vet. Sci. 45: 41 49 Abdulrazak, S. A., R. W. Muinga, W. Thorp, and E. R. Orskov. 1997. The effects of supplementation with Gliricidia sepium or Leucaena leucocephala forage on intake, digestion and live weight gains of Bos taurus x Bos indicus steers offered napiergrass. A nim. Sci. 63:381 388 Adams, D. B. 1989. A preliminary evaluation of factors affecting an experimental system for vaccination and challenge with Haemonchus contortus in sheep. Int. J. Parasitol. 19 : 169 175. Aerts, R. J., T. N. Barry, and W. C. McNabb. 1 999. Polyphenols and agriculture: Beneficial effects of proanthocyanindins in forages. Agric. Ecosyst. Environ. 75:1 12. Agricultural Research Council, 1980. The Nutrient Requirements of Ruminant Livestock. Technical Review. Farnham Royal, U.K.: Commonwea lth Agricultural Bureaux. Agricultural Utilization Research Institute, 2001. The Feasibility of Meat Goats in Minnesota Summary Report. http://www.auri.org. Accessed 25.9.12 Ahima R. S., D. Prabakaran, C. Mantzoros, D. Qu, B. Lowell, E. Flier Maratos, and J. S. Flier, 1996. Role of leptin in the neuroendocrine response to fasting. Nature 382: 250 252. Ahmed, M. M. M. and H. S. Nour. 1997. Legume hays as a supplement for goats during the dry season. Small Rumin. Res. 26: 189 192. Allen, M. S. 1996. Phy sical constraints on voluntary intake of forages by ruminants. J. Anim. Sci. 74:3063 3075. Allen, M. S. 2000. Effects of diet on short term regulation of feed intake by lactating dairy cattle. J. Dairy Sci. 83:1598 1624. Alokan, J. A., 2004. Intake and digestibility by Yankasa sheep of diets containing different proportions of legume and mature grass ( Cynodon nlenfuensis ). J. Agric. Res. and Dev. 3 :1 6 AOAC. 1990. Fiber (Acid Detergent) and Lignin in Animal Feed. No. 973.18 in Official Methods of Analys is. 15th ed. Assoc. Off. Anal. Chem., Arlington, VA. Argyle, J. L., and R. L. Baldwin. 1989. Effects of amino acids and peptides on rumen microbial yields. J. Dairy Sci. 72: 2017 2027.
86 Arvat, E., L. Di Vito, F. Broglio, M. Papotti, G. Muccioli, C. Dieguez, F. F. Casanueva, R. Deghenghi, F. Camanni, and E. Ghigo. 2000. Preliminary evidence that Ghrelin, the natural GH secretagogue (GHS) receptor ligand, strongly stimulates GH secretion in humans. J. Endocrinol. Invest. 23:493 495. Asakawa, A., A. Inui, T. K aga, H. Yuzuriha, T. Nagata, N. Ueno, S. Makino, M. Fujimiya, A. Niijima, and M. A. Fujino. 2001. Ghrelin is an appetite stimulatory signal from stomach with structural resemblance to motilin. Gastroenterol. 120:337 345. Asquith, T. N., and L. G. Butler. 1986. Interactions of condensed tannins with selected proteins. Phytochem. 25: 1591 1593. Asquith, T. N., J. Uhlig, H. Mehansho, L. Putman, D.M. Carlson, and L. Butler. 1987. Binding of condensed tannins to salivary proline rich glycoproteins: the role of carbohydrate. J. Agric.Food Chemi. 35:331 334. Athanasiadou S., I. Kyriazakis, I. Giannenas and T. G. Papchristou. 2009. Nutritional consequences on the outcome of parasitic challenges on small ruminants. Nutritional and foraging ecology of sheep and goa ts. Options Mediterraneennes, 85:29 40. Athanasiadou, S., I. Kyriazakis, F. Jackson, and R. L. Coop. 2000. Consequences of long term feeding with condensed tannins on sheep parasitized with Trichostrongylus colubriformis Int. J. Parasitol. 30: 1025 1033 Athanasiadou, S., I. Kyriazakis, F. Jackson, and R. L. Coop. 2001. Direct anthelmintic effects of condensed tannins towards different gastrointestinal nematodes of sheep. Vet. Parasitol. 99: 205 219. Athanasiadou, S. L., I. Kyriazakis, F. Jackson, and R. L. Coop. 2001a. Direct anthelminthic effects of condensed tannins towards different gastrointestinal nematodes of sheep: invitro and in vivo studies. Vet. Parasitol. 99: 205 219. Aumont G., R. Pouillot, R. Simon, G. Hostache, H. Varo, and N. Barr 19 97. Parasitisme digestif des petits ruminants dans les Antilles franaises. INRA Prod. An. 10: 79 89. Austin, P. J., L. A. Suchar, C. T. Robbins, and A. E. Hagerman. 1989. Tannin binding proteins in saliva of deer and their absence in saliva of sheep and cattle. J. Chem. Ecol. 15:1335 1347. Bahuaud, D., C. Martinez Ortiz, D.E. Montellano, S., Chauveau, F. Prevot, F. Torres Alcosta, I. Fouraste, and H. Hoste. 2006. Effects of four tanniferous plant extracts on the in vitro exsheathment of third stage larv ae of parasitic nematodes. Parasitol. 3: 1 10.
87 Baile, C. A., and J. M. Forbes, 1974. Control of feed intake and regulation of energy balance in ruminants. Physiol. Rev. 54: 16 0 214. Balch, C. C., and R. C. Campling. 1962. Regulation of voluntary food int ake in ruminants. Nutr. Abstr. Rev. 32: 669 686. Balic, A., V. M. Bowles, and E. N. T. Meeusen. 2000a. Cellular profiles in the abomasal mucosa and lymph node during primary infection with Haemonchus contortus in sheep. Vet. Immunol. Immunopathol. 75: 109 120. Balic, A., V. M. Bowles, and E. N. T. Meeusen. 2000b. The immunobiology of gastrointestinal nematode infections in ruminants. Adv. Parasitol. 45: 181 241. Ball D. M., C. S. Hoveland, and G. D. Lacefield 2002. Southern Forages, Third edition, Graph ic Communications Corporation, Lawrenceville, GA, 322 pp. Barahona, R, C. E. Lascano, R. Cochran, J. Morrill and E. C. Titgemeyer. 1997. Intake, digestion, and nitrogen utilization by sheep fed tropical legumes with contrasting tannin concentration and as tringency. J. Anim. Sci.. 75:1633 1640. Barger, I. A., L. F. Le Jambre, J. R. Georgi, and H. I. Davies. 1985. Regulation of Haemonchus contortus populations in sheep exposed to continuous infection. Int. J. Parasitol. 15: 529 533. Barry, T. N., T. R. Man ley and S. J. Duncan. 1986. The role of condensed tannins in the nutritional value of L. pendunculatus for sheep. 4. Sites of carbohydrate and protein digestion as influenced by dietary reactive tannin concentration. Brit. J. Nutr 55:123 137. Barry, T. N and W. C. McNabb. 1999. Review article: The implications of condensed tannins on the nutritive value of temperate forages fed to ruminants Brit. J. Nut. 81:263 272. Barry, T. N., 1985. The role of condensed tannins in the nutritive value of Lotus pedun culatus for sheep. 3. Rates of body and wool growth. Br. J. Nutr. 54: 211 217. Barry, T. N., 1989. Condensed tannins: their role in ruminant protein and carbohydrate digestion and possible effects upon the rumen ecosystem. In: J. V. Nolan; R. A. Leng; D. I. Demeyer (eds.). The Roles of Protozoa and Fungi in Ruminant Digestion. Penambul Books, Armidale NSW 2351, Australia., pp. 153 169. Barry, T. N., McNeill, D. M., McNabb, W. C., 2001. Plant secondary compounds; their impact on nutritive value and upon a nimal production. In: Proc XIX Int Grassland Congress, 11 21 February 2001, Sao Pedro, Sao Paulo, Brazil, pp. 445 452.
88 Bath, G. F., F. S. Malan, and J. A. Van Wyk. 1996. The "FAMACHA Ovine Anaemia Guide to assist with the control of hemonchosis In : Pr oc. 7th Ann. Cong. Liv. Health and Prod. Group of the S. African Vet Assoc ., Port Elizabeth, 5 7 Bath, G. F., J. W. Hansen, R. C. Krecek, J. A. van Wyk, and A. F. Vatta. 2001. Sustainable approaches for managing haemonchosis in sheep and goats. Final Re port of Food and Agriculture Organization (FAO) Technical Co operation Project No. TCP/SAF/8821(A) Food and Agriculture Organization of the United Nations, Rome:26. Baumont, R., S. Prachea, M. Meuretb, and P. Morand Fehr. 2000. How forage characteristics influence behaviour and intake in small ruminants: a review. Liv. Prod. Sci. 64: 15 28 Baxter, N. J., T. H. Lilley, E. Haslam, and M. P. Williamson. 1997. Multiple interactions between polyphenols and a salivary proline rich protein repeat result in com plexation and precipitation. Biochem. 36: 5566 5577. Bergman, E. N. 1990. Energy contributions of volatile fatty acids from the gastrointestinal tract in various species. Physiol. Rev. 70: 567 590. Bernabucci, U., P. Bani, N. Lavetera, and A. Nardone. 19 99. Influence of short and long term exposure to a heat environment on rumen passage rate and diet digestibility by Freisian heifers. J. Dairy Sci. 82: 967 973. Besier, R. B. 1997. Ecological selection for anthelmintic resistance: re evaluation of sheep w orm control programs In : Van Wyk J. A., Van Schalkwyk P. C. (Eds.), Managing anthelmintic resistance in endoparasites, Workshop held at the 16th International Conference of the World Association for the Advancement of Vet Parasitol., Sun City, South Afri ca, pp. 30 38. Bird, P. R., M. J. Watson and J. W. Cayley. 1989. Effect of stocking rate, season and pasture characteristics on live weight gain of beef steers grazing perennial pastures. Aust. J. Agric. Res. 40: 1277 1291 Bisset, S. A., C. A. Morris, D R. Squire, S. M. Hickey and M. Wheeler. 1994. Genetics of resilience to nematode parasites in Romney sheep. New Zealand J. Agric. Res. 37: 521 534. Bisset, S. A., J. A. Van Wyk, G. F. Bath, C. A. Morris, M. O. Stenson, and F. S. Malan. 2001. Phenotypic and genetic relationship among FAMACHA score, faecal egg count and performance data in Merino sheep exposed to Haemonchus contortus infection in South Africa. In: Proc. 5 th Int. Sheep Vet. Congress, Stellenbosch, South Africa.
89 Blaxter, K. L. and R. L. Wilson. 1963. The assessment of crop husbandry techniques in terms of animal production. Anim. Prod. 5: 27 42. Blount, A.R., K.H. Quesenberry, P. Mislevy, R. N. Gates, and T. R. Sinclair. 2001. Bahiagrass and other Paspalum species: An overview of the pl ant breeding efforts in the southern coastal plain. In Proc. 56th Southern Pasture and Forage Crop Improvement Conference, Springdale, AR. Bowman, G. 2003. Why Should You Raise Meat Goats? Bowman Communications Press. Eagle, Idaho, United States. Bowman, J. G. P., C. W. Hunt, M. S. Kerley, and J. A. Paterson. 1991. Effects of grass maturity and legume substitution on large particle size reduction and small particle flow from the rumen of cattle. J. Anim. Sci. 69:369 378. Bown, M. D., D. P. Poppi and A. R Sykes. 1991. The effect of post ruminal infusion of protein or energy on the pathophysiology of Trichostrongylus colubriformis infection and body composition in lambs. Austr. J. Agric. Res. 42: 253 267. Broderick, G. A. 2007. Reduced crude protein rati ons for high producing cows: Production and environmental effects. Page 61 in Proc. Cornell Nutr. Conf., Cornell Univ., Ithaca, NY. Broderick, G. A., 1995. Desirable characteristics of forage legumes for improving protein utilization in ruminants. J. Anim. Sci. 73: 2760 2773. Broderick, G. A., and J. H. Kang. 1980. Automated simultaneous determination of ammonia and total amino acids in rumen fluid and in vitro media. J. Dairy Sci. 63: 64 75. Brooks, C. G., C. W. Garner, M. E. Gehrke, and W. H. Pfander. 19 54. The effects of added fat on the digestion of cellulose and protein by ovine rumen microbes. J. Anim. Sci. 13:758 764. Brunsdon, R. B. 1964. The effect of nutrition on the establishment and persistence of Trichostrongyle infection. N Z Vet. J. 12: 108 111. Bryant, J. P., F. D. Provenza, J. Pastor, P. B. Reichardt, T. P. Clausen, and J. T. du Toit. 1991. Interactions between woody plants and browsing mammals mediated by secondary metabolites. Ann. Rev. Ecol. Syst., 22: 431 446. Bryant, M. P. and I. M Robinson. 1963. Apparent incorporation of ammonia and amino acid carbon during growth of selected species of rumen bacteria. J. Dairy Sci. 46:150 154.
90 Burns J.C, K. R. Pond, and D.S. Fisher. 1994. Measurement of Forage intake. P 494 532. In. G.C. Fahey (ed.) National Conference on Forage Quality, Evaluation, and Utilization held at the University of Nebraska, Lincoln, on 13 15 April 1994 Campling, R. C. 1970. Physical regulation of voluntary intake. In: A. T. Phillipson (ed.) Physiology of Digestion a nd Metabolism in the Ruminant. pp 226 234. Oriel Press, Ltd., Newcastle, U.K. Canale, A., M. E. Valente, and A. Ciotti. 1984. Determination of volatile carboxylic acids (C1 C5) and lactic acid in aqueous acid extracts of silage by high performance liquid chromatography. J. Sci. Food. Agric. 35: 1178 1182. Carulla, J. E. 1994. Forage intake and N utilization by sheep as affected by condensed tannins. Ph.D. Dissertation. University of Nebraska, Lincoln. Chalupa, W. 1968. Problems in feeding urea to ruminan ts. J. Anim. Sci. 27:207 219. Chandra, R. K. 1993. Nutrition and the immune system. Proc. Nutr. Soc. 52: 77 84 Cheeke, P. R. 2005. Applied Animal Nutrition: Feeds and Feeding 3rd ed. Pearson Education Inc., Upper Saddle River, New Jersey. pp. 420 440. Chen, H., X. Li and L. G. Ljungdahl. 1994. Isolation and properties of an extracellular glucosidase from the polycentric rumen fungus Orpinomyces sp. Strain PC 2. Applied and Environ. Microb. 60: 64 70. Chiquette J., K. J.Cheng, J. W.Costerton, and L. P. Milligan. 1988. Effect of tannins on the digestibility of two isosynthetic strains of birdsfoot trefoil ( Lotus corniculatus L.) using in vitro and in sacco techniques. Can. J. Anim. Sci. 68: 751 760. Chiquette, J., K. J. Cheng, L. M. Rode and L. P. Milli gan. 1989. Effects of tannin content in two isosynthetic strains of birdsfoot trefoil ( Lotus corniculantus L.) on feed digestibility and rumen fluid composition in sheep. Can. J. Anim. Sci. 69:1031 1039. Chitwood, M. B. 1957. Intraspecific variation in pa rasitic nematodes. System. Zool. 6: 19 23. Choi, B. R., and D. L. Palmquist. 1996. High fat diets increase plasma cholecystokinin and pancreatic polypeptide, and decrease plasma insulin and feed intake in lactating cows. J. Nutr 126:2913 2919. Clark, J. H., T. H. Klusmeyer, and M. R. Cameron. 1992. Microbial protein synthesis and flows of nitrogen fractions to the duodenum of dairy cows. J. Dairy Sci. 75:2304 2323.
91 Coffey, K. P., G. V. Granade, and J. L. Moyer. 1995. Nutrient content of silages made from whole plant soybeans. Prof. Anim. Sci. 11:74 80. Coffey, L., M. Hale T. H. Terrill, J. A. Masjidis, J. E. Miller and J. M. Burke. 2007. Tools for managing internal parasites in small ruminants: Sericea lespedeza. www.scsrpc.org/SCSRPC/Files/sericea_lespedeza.pdf. Accessed 05.08.12 Conrad, J.H. 1985. Feeding of farm animals in hot and cold environments. In: Yousef, M.K. (Ed.), Stress Physiology in Livestock. CRC P ress, Inc., Boca Raton, Florida, U.S.A., Place, Corvallis, OR 97330, USA. Coop, R. L., and I. Kyriazakis. 2001. Influence of host nutrition on the development and consequences of nematode parasitism in ruminants. Review. Trends Parasitol. 17: 325 330. Co op, R .L. and P. H. Holmes. 1996. Nutrition and parasite Interaction. International J. Parasitol. 26: 951 962 Coop, R. L., A. R. Skye, and K. W. Angus. 1982. The effect of three levels of Ostertagia circumcincta larvae on growth rate, food intake and body composition of growing lambs. J. Agric. Sci. (Camb) 98:247 255. Coop, R. L., and I. Kyriazakis. 1999. Nutrition parasite interaction. Vet. Parasitol. 84: 187 204. Cottle, D. J. 1991, Australian Sheep and Wool Handbook, Inkata Press, Melbourne Australia Coulombe, J. J., and L. Favreau. 1963. A new simple semimicro method of calorimetric determination of urea. Clin. Chem. 9: 102 108. Coyne, M. J., and G. Smith, 1992. The mortality and fecundity of Haemonchus contortus in parasite nave and parasite ex posed sheep following single experimental infections. Int J Parasitol 22: 315 325 Coyne, M. J., G. Smith and C. Johnstone. 1991b. A study of the mortality and fecundity of Haemonchus contortus in sheep following experimental infections. Int. J. Parasi tol 21: 847 853. Cruz Soto, R., S. A. Muhammed, C. J. Newbold, C. S. Stewart, and R. J. Wallace. 1994. Influence of peptides, amino acids and urea on microbial activity in the rumen of sheep receiving grass hay on the growth of rumen bacteria in vitro. A nim. Feed Sci. Technol. 49:151 161.
92 Cummings, D. E., J. Q. Purnell, R. S. Frayo, K. Schmidova, B. E. Wisse and D. S. Weigle, 2001. A preprandial rise in plasma ghrelin levels suggests a role in meal initiation in humans. Diabetes 50: 1714 1719 Dahl, G. E., 2006. Effect of photoperiod on feed intake and animal performance. Proc. Tri State Dairy Nutrition Conference, pp. 33 36 April, 25 26, Fort wayne, Indiana. Dakkak, A., J. Fioramonti J. and L. Bueno. 1981. Haemolichus contortus third stage larvae in sheep: kinetics of arrival in the abomasum and transformation during the rumino omasal transit. Res. Vet Sci. 31: 384 385. Datta, F. U., J. V. Nolan, J.B. Rowe, and G. D. Gray. 1998. Protein supplementation improves the performance of parasitised sheep fed a straw based diet. Int. J. Parasitol. 28: 1269 1278 Decruyenaere, V., A. Buldgen and D. Stilmant. 2009. Factors affecting intake by grazing ruminants and related quantification methods: Review. Biotech. Agro. Soc. Envi r on. 13: 559 573. Deetz, D. A ., H. G. Jung, R. F. Helm, R. D. Hatfield, and J. Ralph. 1993. Impact of methyl 5 O (E) feruloyl c L arabinofuranoside on in vitro degradation of cellulose and xylan. J. Sci. Food Agric. 61:423. Demircan V., H. Koknaroglu and H. Yilmaz. 2007. Effect of se ason on b eef cattle performance and profitability. Agricultura Tropica Subt r opica 40: 19 23 Devendra, C. 1990. Goat production: An international perspective. In: Proc. International Goat Production Symp., Oct. 22 25, 1990. Florida A and M University, T allahassee, FL. Devendra, C. and Burns, M. 1983. Goat Production in the Tropics. Commonwealth Agricultural Bureaux (CAB). Farnham Royal, UK. 184pp. Dineen, J. K., P. Gregg, and A. K. Lascelles. 1978. The response of lambs to vaccination at weaning with i rradiated Trichostrongylus columbriformis larvae: segregation into "responder s and "non responders". Int. J. Parasitol. 8:59 66. Dobson, C. and R. Oesophagostomum calumbiamon : effects of low protein d iet on resistance to 255. Donaldson, J. M. F. J. van Houtert, and A. R. Sykes. 1998. The effect of nutrition on the periparturient parasite status of mature ewes. Anim. Sci. 67: 523 533.
93 Donalds on, J., van Houtert, M. F. J., Sykes, A. R., 1998. The effect of nutrition on the periparturient parasite status of mature ewes. Anim. Sci. 67 : 523 533. Driedger, A. and E. Hatfield. 1972. Influence of tannins on the nutritive value of soybean meal for r uminants. J. Anim. Sci. 34: 465 468. Dubeuf, J. P., P. Morand Fehr, and R. Rubino. 2003. Situation, changes and future of goat industry around the world. Small Rumin. Res. 51: 165 173. Duble, R. L., J. A. Lancaster, and E. C. Holt. 1971. Forage character istics limiting animal performance on warm season perennial grasses. Agron. J. 63:795 798. Egan, A. R., and M. J. Ulyatt. 1980. Quantitative digestion of fresh herbage by sheep. VI. Utilization of nitrogen of five herbages. J. Agric. Sci., 94: 45 56. Ehu i, S. K., S. Benin, and G. Nega. 2000. Factors affecting urban demand for live sheep: The case of Addis Ababa, Ethiopia. Socio economics and Policy Research Working Paper 31. ILRI (International Livestock Research Institute), Nairobi, Kenya. p 32 Ejlerts en, M., S. M. Githigia, R. O. Otieno, and S. M Thambsborg. 2006. Accuracy of an anaemia scoring chart applied on goats in sub humid Kenya and its potential for control of Haemonchus contortus infections. Vet. Parasitol. 141: 291 301. Elmquist, J. K., C. F Elias, and C. B. Sape. 1999. From lesions to leptin: hypothalamic control of food intake and body weight. Neuron 22: 231 254 Elrod, C. C. and W. R. Butler. 1993. Reduction of fertility and alteration of uterine pH in heifers fed excess ruminally degrad able protein. J. Anim. Sci. 71: 694 701. Farverdin, P., R. Baumont, and K. L. Ingvartsen. 1995. Control and prediction of feed intake in ruminants. Proc IVth International Symposium on the nutrition of herbivores, recent developments in the nutrition of herbivores. INRA Edition, Paris, pp. 95 120. FAWN, 2011. Florida Automated Weather Network, Marianna, FL. Archived Weather Database. http://fawn.ifas.ufl.edu/data/ Accessed August, 2012. Fei H.E., P. Qiu H ong, S. Ying, and D. Chang Qing. 2008. Biosynthesis and genetic regulation of proanthocyanidins in plant s. Rev. Molec. 13: 2674 2703. Ferguson, J. D., D. T. Galligan, T. Blanchard, and M. Reeves. 1993. Serum urea nitrogen and conception rate: The usefulne ss of test information. J. Dairy Sci. 76:3742 3746.
94 Fernandes, M. H. M. R., K. T. Resende, L. O. Tedeschi, J. S. Jr. Fernandes, H. M. Silva, G. E. Carstens, T. T. Berchielli, I. A. M. A. Teixeira, and L. Akinaga. 2007. Energy and protein requirements for maintenance and growth of Boer crossbred kids. J. Anim. Sci. 85: 1014 1023. Fikru, R., T. Sori, R. Dhuguma, and Y. Kiros. 2006. Epidemiology of gastrointestinal parasites of ruminants in Western Oromia, Ethiopia. Intl J. App. Res. Vet Medi. 4: 51 57. Foley, W. J., G. R. Iason, and C. McArthur. 1999. Role of plant secondary metabolites in the nutritional ecology of mammalian herbivores: How far have we come in 25 years? Nutritional Ecology of Herbivores. Proc. Vth Int. Symp. Nutrition of Herbivores. H. Joachim, G. Jung, and G. C. Fahey Jr., ( ed s ) American Society of Anim. Sci., Savoy, Il. Foo, L. Y., W. T. Jones, L. J. Porter, and V. N. Williams. 1986. Proanthocyanidin polymers of fodder legumes. Phytochem. 21:933 935. Foo, L. Y., Y. Lu, W. C. McNabb, G. C. Waghorn, and M. J. Ulyatt. 1997. Proanthocyanidins from Lotus pedunculatus. Phytochem. 45: 1689 1696 Foo, L Y, R. Newman, G. C. Waghorn, W. C. McNabb, and M. J. Ulyatt. 1996. The proanthocyanidins of Lotus corniculatus. Phytochemi. 41: 617 624. Forbes, J. M. 1995. Voluntary food intake and diet selection in farm animals. In: J. P. F. Mello (ed.). Farm animal metabolism and nutrition. Physiological and metabolic aspects. CAB International 2000 Wallingford, UK, Chapter 15, p. 319 333 Forbes, J. M., 1996. Integration of regulatory signals controlling forage intake in ruminants. J. Anim. Sci 74: 3029 3035. Foster, J. L., A. T. Adesogan, J. N. Carter, A. R. Blount, R. O. Myer and S. C. Phatak. 2009. Intake, digestibility, and nitrogen retention by sheep supplemented with warm season legume haylages or soybean meal. J. Anim. Sci. 87:2899 2905 Fox, D. G., C. J.Sniffen, and J. D. beef cattle for animal and environmental variations. J. Anim. Sci. 66: 1475 1495. Fox, M. T., 1997. Pathophysiology of infection with gastrointestinal nematodes in domestic ruminants: recent developments. Vet Parasitol. 72: 285 308. Frutos, P., G. Hervs, F. J. Girldez and A. R. Mantecn. 2004. Review. Tannins and ruminan t nutrition. Span. J. Agri. Res. 2: 191 202. Galal, S. 2005. Biodiversity in goats. Small Rumin. Res. 60: 75 81.
95 Gall, C. 1981. Goat Production. Academic Press, London, UK. Galyean, M. L., and A. L. Goetsh. 1993. Utilization of forage fiber by ruminants In: H. G. Jung, D. R. Buxton, R. D. Hatfield, and J. Ralph (ed.). Forage Cell Wall Structure and Digestibility. ASA CSSA SSSA, Madison, Wisconsin, pp. 33 71 Garces Yepez, P., W. E. Kunkle, D. B. Bates, J. E. Moore, W. W. Thatcher, and L. E. Sollenberge r. 1997. Effects of supplemental energy source and amount on forage intake and performance by steers and intake and diet digestibility by sheep. J. Anim. Sci. 75:1918 1925. Gates, D.M. 1968. Physical Environment daptation of Domestic Animals E.S.E. Hafez (Ed.) Adaptation of domestic animals. Lea and Febiger, Philadelphia, PA, USA. Gates, R. N., P. Mislevy, and F. G. Martin. 2001. Herbage accumulation of three bahiagrass populations during the cool season. Agron. J. 93:112 117 Gelaye, S., and E. Amoah. 1991. Chevon and its production. In: T. H. Teh (Ed.) National Symp. on Goat Meat Production and Marketing. p 125. Tulsa, OK. Getachew G., A.N. Said, and F. Sundstol. 1994. The effect of forage legume supplementation on digestibility and body weight gain by sheep fed a basal diet of maize stover. Anim. Feed Sci. Technol. 46:97 108. 006. In. Sande, D. N., J. E. Houston, and J. E. Epperson. 2005. The relationship of consumin g populations to meat goat production in the United States. J. Food Distri. Res. 36:156 160 Gibb M. J., C. A. Huckle, R. Nuthall, and A. J. Rook, 1999. The effect of physiological state (lactating or dry) and sward surface height on grazing behaviour an d intake by dairy cows. Appl. Anim. Behav. Sci. 63: 269 287. Gilboa, N., 1995. Negative effects of tannins on livestock and their neutralization. Ph.D. thesis, The Hebrew University of Jerusalem, Jerusalem, Israel. Giralt, M., and P. Vergara. 1999. Gluca gonlike peptide 1 (GLP 1) participation in ideal brake induced by intraluminal peptones in rat. Dig. Dis. Sci. 44: 322 329. Glimp, H. A. 1995. Meat goat production and marketing. J. Anim. Sci. 73: 291 295. Gochman, N., and J. M. Scmidz. 1972. Application of new peroxide indicator reaction to the specific, automated determination of glucose with glucose oxidase. Clin. Chem. 18: 943 952.
96 Goldstein, J. L., and T. Swain 1963. Changes in tannins in ripening fruits. Phytochem 2 : 371 383. Goodchild, A. V., an d N. P. McMeniman. 1994. Intake and digestibility of low quality roughages when supplemented with leguminous browse. J. Agric. Sci., Camb. 122: 151 160. Gordon, H. M. 1948. The epidemiology of parasitic diseases, with special reference to studies with nema tode parasites of sheep. Aust. Vet. J. 24: 17 44. Grider, J. R. 1994. Role of cholecystokinin in regulation of gastrointestinal motility. J Nutr 124:1334S 1339S. Gwasdauskas, F. C. 1985. Effeect of climate on reproduction in cattle. J. Dairy Sci. 68: 1 568 1578. Haenlein, G. F. W., 1992. Alternatives in dairy product market. In: Scarfe, A.D. (Ed.), Proceedings of the Sheep and Goat Industry Development Symposium. Tuskegee University, AL. Hagerman, A. E. and C. T. Robbins. 1993. Specificity of tannin bi nding salivary proteins relative to diet selection by mammals. Can. J. Zool. 71: 628 633. Hagerman, A. E. and C. T. Robbins. 1987. Implications of soluble tannin protein complexes for tannin analysis and plant defense mechanisms. J. Chem Ecol. 13: 1243 1 259. Hagerman, A. E. and L. G Butler. 1994. Assay of condensed tannins or flavonoid oligomers and related flavonoids in plants. Meth Enzymol. 234: 429 437. Hagerman, A. E. and L. G. Buttler. 1981. The specificity of proanthocyanidin protein interactions. J. Biol. Chem 256: 4494 4497. Hagerman, A. E., and L. G. Butler. 1978. Protein precipitation method for the quantitave determination of tannins. J. Agric. Food Chem 26: 809 812. Hagerman, A. E., and L. G. Butler. 1991. The specificity of proanthocyani din protein interactions. J. Biol. Chem. 256: 4494 4497. Hale, M. 2006. Managing Internal Parasites in Sheep and Goats. ATTRA publication. http://attra.ncat.org/attra pub/parasitesheep.html Hannah, S. M., R. C. Cochran, E. S. Vanzant, and D. L. Harmon. 1991. Influence of protein supplementation on site and extent of digestion, forage intake, and nutrient flow characteristics in steers consuming dormant bluestem range forage. J. Anim. Sci. 69:2624 2633.
97 Hammond, A. C. 1997. Update on blood urea nitrogen and milk urea nitrogen as a guide for protein supplementation in cattle. dairy.ifas.ufl.edu/rns/1997/frns 1997.pdf. Accessed September, 5, 2012 Haslam, E. 1982. Proanthocyanidins. In: J.B Harborme and T.J. Mabrey (eds), The Flavonoids: Advances in research. Champman and Hall, London, UK. Haslam, E. 1989. Plant Polyphenols Vegetable Tannins Revisited. Cambridge University Press, Cambridge, U.K. Hervs, G., P. Frutos, F. J. Girldez, A. R. Mantecn, and M. C. lvarez Del Pino. 2003. Effect of different doses of quebracho tannins extract on rumen fermentation in ewes. Anim. Feed Sci. Tech. 109: 65 78. Hiroshi, H., M. Kojima and K. Kagawa. 2002. Ghrelin and the regulation of food intake an d energy balance. Review. Molec. Interven. 2: 495 503 Holmes, P. H. 1993. Interactions between parasites and animal nutrition: the veterinary consequences. Proc. Nutr Soc. 52: 113 120. Holmes, P. H., 1985. Pathogenesis of trichostrongylosis. Vet. Paras itol. 18: 89 101. Holmes, P. H., 1987. Pathophysiology of parasitic infections. Parasitol. 94: 29 51. Holter, J. B., J. W. West and M. L. McGilliard. 1997. Predicting ad libitum dry matter intake and yield of Holstein cows. J. Dairy Sci. 80: 2188 2199. Horak, I. G. 1978. Parasites of domestic and wild animals in South Africa. Helminths in sheep on dryland pasture on the Transvaal Highveld. Onderstepoort J. Vet. Res. 45: 16 Horak, I. G. and J. P. Louw. 1977. Parasites of domestic and wild animals in Sout h Africa. IV. Helminths in sheep on irrigated pastures on the Transvaal Highveld. Onderstepoort J. Vet. Res. 44: 261 270 Horigome, T., R. Kumar, and K. Okamoto. 1988. Effects of condensed tannins prepared from leaves of fodder plants on digestive enzymes in vitro and in the intestine of rats. Brit. J. Nutr 60: 275 285. Hoste, H. 2001. Adaptive physiological processes in the host during gastrointestinal parasitism. Int. J. Parasitol. 31: 231 244. Hume, I. D., R. J. Moir, and M. Somers. 1970. Synthesis o f microbial protein in the rumen. I. Influence of level of nitrogen intake. Aust. J. Agric. Res. 21: 283.
98 Hunter, R. A. 1991. Strategic supplementation for survival, reproduction and growth of cattle. In: Proc. 2nd Grazing Livestock Nutr. Conf., Stillwate r. Oklahoma Agric. Exp. Sta. MP 133. Pp 32 47. Institute of Biodiversity Conservation (IBC) Genetic Resources: Country Report. A Contribution to the First Report on the es. IBC, May 2004. Addis Ababa, Ethiopia. Igono, M. O., B .J. Steevens, M. D. Shanklin, and H. D. Johnson. 1985. Spray cooling effects on milk production, milk and rectal temperatures of cows during a moderate temperature summer season. J. Dairy Sci. 68: 979 985. Ingvartsen, K. L., H. R. Anderson, and J. Foldager. 1992. Random variation in voluntary dry matter intake and the effect of day length on feed intake capacity in growing cattle. Acta Agric. Scand 42: 121 126. Ishler, V. and J. Heinrichs. 1996. From feed to milk: Understanding rumen function. Penn State Cooperative Extension Extension Circular 422. Pennsylvania Jackson, F., I. R. P. Miller, G. F. J. Newlands, S. E. Wrigilt, and L. A. Hay. 1988. Immune exclusion of Haemonchus contortus larvae i n sheep: dose dependency, steroid sensitivity and persistence of the response. Res Vet Sci 44: 320 323. Johnson, C. R., B. A. Reiling, P. Mislevy and M. B. Hall. 2001. Effects of nitrogen fertilization and harvest date on yield, digestibility, fiber, a nd protein fractions of tropical grasses. J. Anim. Sci. 79: 2439 2448. Johnson, D. 1995. Composition and Quality of Goat Meat Produced. Simpson J.R. ed. 39 41: Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Johnson, H. D., A. C. Ragsdale, I. L. Berry and M. D. Shankin. 1963. Temperature humidity effects including influence of acclimation in feed and water consumption of Holstein cattle. Univ. of Missouri Res. Bull. No. 846. Jones, W. T., and J. L. Mangan. 1977. Complexes of the condensed tannins of sanfoin ( Onobrychis viciifolia Scop.) with fraction 1 leaf protein and with submaxillary mucoprotein and their reversal by polyethylene glycol and pH. J. Sci. Food Agric. 28:126 136. Jones, W. T., R. B. Broadhurst and J. Lyttleton. 1976. The condensed tannins of pasture legume species. Phytochem 15: 1407 140 9
99 Jung, H. G., and D. A. Deetz. 1993. Cell wall lignification and degradability. In: H.G. Jung, D. R. Buxton, R. D. Hatfield, and J. Ralph (Ed.) Forage Cell Wall Structure and Digestibility. p 315. ASA CSSA SSSA, Madison, WI. Jung, H. G., and M. S. Allen. 1995. Characteristics of plant cell walls affecting intake and digestibility of forages by ruminants. J. Anim. Sci. 73: 2774 2790. Kambara, T. R. G. McFarlane, T. J. Abell, R. W. McAnulty and A. R. Skye. 1993. The effect of age and dietary protein on immunity and resistance in lambs vaccinated with Trichostrongylus colubriformis Int. J. Parasitol. 23: 471 476. Kamegai, J., H. Tamura, T. Shimi zu, S. Ishii, H. Sugihara, and I. Wakabayashi. 2001. Chronic central infusion of ghrelin increases hypothalamic neuropeptide Y and Agouti related protein mRNA levels and body weight in rats. Diab. 50: 2438 2443. Kaplan, R. M. 2004. Drug resistance in nema todes of veterinary importance: a status report. Trends Parasitol. 20: 477 481. Kaplan, R. M., A. N. Vidyashankar, S. B. Howell, J. M. Neiss, L. H. Williamson, and T. H. Terrill. 2007. A novel approach for combining the use of in vitro and in vivo data t o m easure and detect emerging moxidectin resistance in gastrointestinal nematodes of goats. Int. J. Parasitol. 37: 795 804. Kartchner, R. J. 1981. Effects of protein and energy supplementation of cows grazing native winter range forage on intake and diges tibility. J. Anim. Sci. 51:432 438. Kenako, J. J. 1989. Pages 886 891 in Clinical biochemistry of domestic animals. Acad. Press, NY. Kimambo, A. E., J. C. MacRae, A. Walker, C. F. Watt and R. L. Coop. 1988. Effect of prolonged subclinical infection with Trichostrongylus columbriformis on the performance and nitrogen metabolism of growing lambs. Vet. Parasitol. 28: 191 203. Knox, M. R., and J. W. Steel. 1996. Nutritional enhancement of parasite control in small ruminant production systems in developing co untries of South East Asia and the Pacific. Int. J. Parasitol. 26:963 970. Knox, M. R., and J. W. Steel. 1999. The effects of urea supplementation on production and parasitological responses of sheep infected with Haemonchis contortus and Trichostrongylu s columbriformis Vet. Parasitol. 83: 123 135 Koknaroglu, H., D. D. Loy, and M. P. Hoffman. 2005a. Effect of housing, initial weight and season on feedlot performance of steers in Iowa. South African J. Ani m Sci. 35:281 289.
100 Kosgey, I. S., G. J. Rowlan ds, J. A. M. Van Arendonk, and R. L. Baker. 2008. Small ruminant production in smallholder and pastoral/extensive farming systems in Kenya. Small Rumin. Res. 77: 11 24. Kostenbauder M. J., S. W. Coleman, C. C. Chase Jr., W. E. Kunkle, M. B. Hall, and F. G Martin. 2007. Intake and digestibility of bahiagrass hay by cattle that are supplemented with molasses or molasses urea with or without soybean hulls. Prof. Anim. Sci. 23:373 380. Kumar, R. and M. Singh. 1984. Tannins, their adverse role in ruminant nut rition. J. Agr. Food Chem., 32: 447 53. Kumar, R., and S. Vaithiyanathan. 1990. Occurrence, nutritional significance and effect on animal productivity of tannins in tree leaves. Anim. Feed Sci. Tech. 30: 21 38. Lacroux, C., T. Nguyen, O. Andreoletti, F. Prevot, C.Grisez, J. Bergeaud, L. Gruner, J. Brunel, D. Fracois, P. Dorchies, P. Jacquiet. 2006. Haemonchus contortu s (Nematode: Ttrichostrongylidae ) infection in lambs elicits an equivocal The immune response. Vet. Res. 37: 607 622 Lange, K., D. Olcott, J. E. Miller, J.A. Mosjidis, T. H. Terrill, and J. M. Burke. 2005. Effect of the condensed tannin containing forage, sericea lespedeza, fed as hay, on natural and experimental challenge infection in lambs. Proc. ASAS Southern Sections Meeting, Little Rock AR, pp. 15 16. Lange, K., .D. Olcott, J. E. Miller, J. A. Mosjidis, T. H. Terrill, J. M. Burke, and M. T. Kearney. 2006. Effect of sericea lespedeza ( Lespedeza cuneata ) fed as hay, on natural and experimental Haemonchus contortus infections in lambs. Ve t. Parasitol. 141: 273 278. Laurence, G. B., J.W. Groenewald, J. I. Quinn, R. Clark, R. S. Ortlepp, and S. W. Bosman 1951. The influence of nutritional level on verminosis in Merino lambs. Onderstepoort J. Vet. Res. 25: 121 132. Lazzarini, I., E. Detma nn, C. B. Sampaio, M.F. Paulino, S. C. Valadares Filho, M. A. Souza, and F. A. Oliveira. 2009a. Dinmicas de trnsito e degradao da fibra em detergente neutro em bovinos alimentados com forragem tropical de baixa qualidade e compostos nitrogenados. Arqui vo Bras. Medici. Vet. Zoot. 61: 635 647. Leep ,R., P. Jeranyama D. H. Min D. H., T. Dietz, S. Bughrara, and J. Isleib. 2002. Grazing effects on herbage mass and composition in grass birdsfoot trefoil mixtures. Agron. J. 94:1257 1262.
101 Leinmuller, E., H. S teingass, and K. H. Menke, 1991. Tannins in ruminant feedstuffs. Biannual Collection of recent German contributions concerning development. Anim. Res. 33: 9 62. Leite Browning, M. L. 2006. Haemonchus contortus (Barber pole Worm) infestation in goats. Bar ber Pole Worm infestation in goats University of Alabama A&M. 2 December 2010. http://www.aces.edu/pubs/docs/U/UNP 0078/ Accessed 26. 06. 2011 Leng, R. A. and J. V. Nolan. 1984. Nitrogen metabol ism in the rumen. J. Dairy Sci. 67: 1072 1089. Leng, R. A., J. V. Nolan, and T. R. Preston. 1983. Rumen bypass nutrients: manipulation and implications. In, Nuclear Techniques for Assessing and Improving Ruminant Feeds (Vienna) FAO: Int. Atomic Energy Agen cy pp 89 104 Liddle, R. A., I. D. Goldfine, M. S. Rosen, R. A. Taplitz, and J. A. Williams. 1985. Cholecystokinin bioactivity in human plasma. Molecular forms, responses to feeding, and relationship to gallbladder contraction. J. Clin. Invest. 75: 1144 1 152. Lindroth, R. L., and G. O. Batzli. 1984. Plant phenolics as chemical defenses: effects of natural phenolics on survival and growth of prairie voles. J. Chem. Ecol. 10: 229 244. Linn, J. G., and N. P. Martin. 1999. Forage quality tests and interpreta tions. WW 02637. Leaf loss DDMI.html. Accessed August, 2012. Loomis, W.D., and J. Battaile. 1966. Plant polyphenolic compounds and isolation of plant enzymes. Phytochem. 5: 423 438. Luginbuhl, J. M. 1998. Breeds of Goats for Meat Goat Production and Prod uction Traits. North Carolina State University, Animal Science Extension Service: Raleigh NC Luginbuhl, J. M. 2000. Breeds and Production Traits of Meat Goats. [Electronic version]. Animal Science Facts, ANS 00 603MG. North Carolina Cooperative Extensio n Service, North Carolina State University Web site: http://www.cals.ncsu.edu/an_sci/extension/animal/meatgoat/pdf_factsheets/ANS %2000%20603MG.pdf Accessed 20. 11. 2011 Luginbuhl, J. M., J. T. Green, J. P. Mueller, and M. H. Poore. 1996. Meat goats in land and forage management. In: Proceedings of the Southeast Regional Meat Goat Production Symposium, Florida A&M University, Talahassee, FL, Febru ary 21 24.
102 Luikart, G., L. Gielly, L. Excoffier, J. D. Vigne, J. Bouvet, and Taberlet, P., 2001. Multiple maternal origins and weak plylogeographic structure in domestic goats. Proc. Natl. Acad. Sci. U.S.A. 98: 5927 5932. MacRae, J. C. 1993. Metabolic co nsequences of intestinal parasitism. Proc. Nutr Soc. 52: 121 130 Makie, R. I. and M. Morrison. 1995. Nitrogen metabolism in the rumen. Biotechnological problems and prospects. In: Wallace, R.J., and A. Lahlou Kassi. 1995. Rumen Ecology Research Planning Proceedings of a workshop held at ILRI, Addis Ababa. Ethiopia. Pp. 31 49. Malan, F. S., and J. A. Van Wyk. 1992. The packed cell volume and colour of the conjunctivae as aids for monitoring Haemonchus contortus infestations in sheep, in: Anonymous, Proc eedings of the South African Vet. Assoc. Biennial National Vet. Congress, Grahamstown, p. 139. Malan, F. S., J. A. Van Wyk, and C. D. Wessels. 2001. Clinical evaluation of anaemia in sheep: early trials, Onderstepoort J. Vet. Res. 68: 165 174. Mamoon, R 2008. Goats and their Nutrition. Manitoba goat Association. Manitoba Agriculture, Food and rural initiatives. www.gov.mb.ca/agriculture/livestock/goat/pdf/bta01s08.pdf Acce ssed 15. 06. 2012. Mangan, J. L. 1972. Quantitative studies on nitrogen metabolism in the bovine rumen. Brit. J. Nutr 27: 261 283. Mangan, J. L. 1988. Nutritional effects of tannins in animal feeds. Nutr Res. Rev. 1: 209 231. Manton, V. J. A., R. Peac ock, D. Poynter, P. H. Silverman and R. J. Terry. 1962. The influence of age on naturally acquired resistance to Haemonchus contortus in lambs. Res. Vet Sci. 3:308 314. Mathis, C. P., R. C. Cochran, J. S. Heldt, B. C. Woods, I. E. O. Abdelgadir, K. C. Ol son E. C. titgemeyer, and E. S. Vanzant. 2000. Effects of supplemental degradable intake protein on utilization of medium to low quality forages. J. Anim. Sci. 78: 224 232. Matizha, W., N. T. Ngongoni, and J. H. Topps. 1997. Effect of supplementing veld hay with tropical legumes Desmodium uncinatum, Stylosanthes guianensis and Macroptilium atropurpureum on intake, digestibility, outflow rates, nitrogen retention and live weight gain in lambs. Anim. Feed Sci. and Technol. 69:187 193.
103 Maxey, K. 1993. Year of progress. Dairy Goat J. 11 : 32. McArthur, C., G. D. Sanson, and A. M. Beal. 1995. Salivary proline rich proteins in mammals: roles in oral homeostasis and counteracting dietary tannin. J. Chem Ecol.. 21: 663 691. McDonald, M., P. Edwards, J. F. D. Gr eenhalgh, and C. A. Morgan. 1995. Animal Nutrition. Longman, London, UK, 543 pp. McKenzie Jakes, A. 2007. Getting started in the meat goat business; Trends, Development s Challenges and Opportunities in the Meat Goat Industry in Southeastern United States Florida A&M University, College of Engineering Sciences, Technology, and Agriculture Research and Cooperative Extension Programs,Statewide Goat Program. Bulletin 1 vol. 1, pp 1 18 McLeod, M. N. 1974. Plant tannins Their role in forage quality. Nutr. Abst. Rev. 44: 803 812. McMahon, L. R., W. Majak, T. A. McAllister, J. W. Hall, G. A. Jones, J. D. Popp, and K. J. Cheng. 1999. Effect of sainfoin on in vitro digestion of fresh alfalfa and bloat in steers. Can. J. Anim. Sci. 79:203 212. McNabb, W. C., G. C. Waghorn, J. S. Peters and T. N. Barry. 1996. The effect of condensed tannins in Lotus pedunculatus on the solubilisation and degradation of ribulose 1 5 bisphosphate carboxylase (Rubisco) protein in the rumen and sites of Rubisco digestion. Brit. J. Nutr 76: 535 549. McSweeney, C. S., B. Palmer, D. M. McNeil, and D. O. Krause. 2001. Microbial interactions with tannins: nutritional consequences for ruminants. Anim. Feed Sci. Technol. 91: 83 93. Mehansho, H., Butler, L. G. and Carlson, D. M. 1987. Dietary tannins and salivary proline rich proteins: interactions, inductions and defense mechanisms. Ann. Rev. Nutr. 7: 423 440. Melanie, E. B K Knoll, L F. Kime, and J K. Harper. 2012; Meat Goat Production. Penn State Cooperative Extension. Agricul tural Alternatives, Code# UA 340. http://agalternatives.aers.psu.edu/livestock/meatgoat/meat goat.pdf Accessed, May, 2012 Mertens, D. R. 1973. Application of theoretical mathematical models to cell wall digestion and forage intake in ruminants. Ph.D. Thesis. Cornell Univ., Ithaca, NY. Mertens, D. R. 1994. Regulation of forage intake. P 450 493. In. G.C. Fahey, ( ed. ) National Conference on Forage Quality, Evaluation, and Utilization held at the University of Nebraska, Lincoln, on 13 15 April 1994
104 Miller, D. K., and T. M. Craig, 1996. Use of anthelmintic combinations against multiple resistant Haemonchus contortus in Angora goats. Small Rumin. Res. 19: 281 283. Miller, E. L. 1973. Symposium on nitrogen utilization by the ruminant. Evaluation of foods as sources of nitrogen and amino acids. Proc. Nutr Soc. 32: 79. Miller, H. R., F. Jackson, G. Newlands, and W. T. Appleyard. 1983. Immune exclusion, a mechanism of protect ion against the ovine nematode Haemonchus contortus Res. Vet. Sci. 35:357 63. Miller, J. E., M. Bahitathan, S. L. Lemarie, F. G. Hembry, M. T. Kearney, and S. R. Barras. 1998. Epidemiology of gastrointestinal nematode parasitism in Suffolk and Gulf Coast native sheep with special emphasis on relative susceptibility to Haemonchus contortus infection. Vet. Paras i tol. 74:55 74 Min, B. R., D. Miller, S. P. Hart, G. Tomita, E. Loetz, and T. Sahlu. 2003b. The effect of grazing forage containing condensed tan nins on gastro intestinal parasite infection in Angora does. Vet. Parasitol. (In press) Min, B. R., and S. P. Hart. 2003. Tannins for suppression of intestinal parasites. J. Anim. Sci. 81: E102 E109. Min, B. R., S. P. Hart, D. Miller, G. M. Tomita, E. L oetz and T. Sahlu. 2005. The effect of grazing forage containing condensed tannins on gastrointestinal parasite infection and milk composition in Angora goats. Vet Parasitol. 130: 105 113. Min, B. R., T. N. Barry, G. T. Attwood, and W. C. McNabb. 2003. T he effect of condensed tannins on the nutrition and health of ruminants fed fresh temperate forages: a review. Anim. Feed Sci. Technol. 106: 3 19. Min, B .R., W. E. Pomroy, S. P. Hart, and T. Sahlu. 2004 The effect of short term consumption of a forage co ntaining condensed tannins on gastro intestinal nematode parasite infections in grazing wether goats. Small Rumin. Res. 51: 279 283. Minson, and Wilson, 1994. Prediction of intake as an element of forage quality. In George C. Fahey Jr. (ed.) Forage quanti ty, evaluation and utilization. Madison, Wis.: ASA CSSA SSSA P 533 563. Minson, D. J. 1990. Forage in Ruminant Nutrition Academic press Inc., San Diego, CA. Minson, D.J and R. Milford. 1967. The voluntary intake and digestibility of diets containing different proportions of legume and mature Pangola grass ( Digitaria decumbens ). Aust. J. Experi. Agri. Anim. Husb., 7: 546 551
105 Molan, A. L., G. C. Waghorn and W. C. McNabb. 2002. Effect of condensed tannins on egg hatching and larvae development of Trich ostrongylus columbriformis in vitro. Vet. Res. 19: 65 69. Molan, A. L., G. C. Waghorn, B. R. Min, and W. C. McNabb. 2000. The effect of condensed tannins from seven herbages on Trichostrongylus colubriformis larval migration in vitro. Folia Parasitol 47: 39 44. Mole, S. and P. G. Waterman. 1987. A critical analysis of techniques for measuring tannins in ecological studies: 2 Techniques for biochemically defining tannins. Oecologia (Berlin) 72: 148 156. Moore, D. A., T. H. Terrill, B. Kouakou, S. A. Shai k, J. A. Mosjidis, J. E. Miller, M. Vanguru, G. Kannan and J. M. Burker. 2008. The effects of feeding sericea lespedeza hay on growth rate of goats naturally infected with gastrointestinal nematdes. J. Anim. Sci. 2008. Moore, J. E, M. H. Brant, W. E. Kun kle, and D. I. Hopkins 1999. Effects of supplementation on voluntary forage intake, diet digestibility, and animal performance J. Anim. Sci. 77:122 135. Moore, J. E., W. E., Kunle, W. F., Brown. 1991. Forage quality and the need for protein and energy s upplements. Pages 113 123 .Proc Beef Cattle Short Course, Dept Anim. Sci., University of Florida, Gainesville. Moors, E. and M. Gauly. 2009. Is the FAMACHA chart suitable for every breed? Correlations between FAMACHA scores and different traits of mucosa colour in naturally parasite infected sheep breeds. Vet Parasitol. 166: 108 111 Moran, T. H., and K. P. Kinzig. 2004. Gastrointestinal satiety signals II. Cholecystokinin. Am J Physiol. 286: G183 G188. Moran, T. H., E. E. Ladenheim, and G. J. Schwart z, 2001. Within meal gut feedback signaling. Int J Obes Relat Metab Dis 25: S39 S41 Morand Fehr, P., E. Owen and S. Giger Reverdin. 1991. Feeding behaviour of goats at the trough. In: Morand Fehr, P (ed.) Goat Nutrition. EAAP, Wageningen, pp. 3 12 Morand Fehr, P., J. P. Boutonnet, C. Devendra, J. P. Dubeuf, G. F. W. Haenlein, P. Holst, L. Mowlem, and J. Capote, 2004. Strategy for goat farming in the 21st century. Small Rumin. Res. 51: 175 183.
106 Mortensen, L. L., L. H. Williamson, T. H. Terril l, R. Kircher, M. Larsen, and R. M. Kaplan, 2003. Evaluation of prevalence and clinical implications of anthelmintic resistance in gastro intestinal nematodes of goats. J.Anim. Vet. Med. Assoc. 23: 495 500. Mosi, A. K., and M. H. Butterworth. 1985. The vo luntary intake and digestibility of combinations of cereal crop residues and legume hay for sheep. Anim. Feed Sci. and Technol. 12:241 251. Mueller Harvey I., J. D. Reed, and R. D.Hartley, 1987. Characterization of phenolic compounds including flavanoids and tannins of ten Ethiopian browse species by high performance liquid chromatography. J. Sci. Food and Agri. 39: 1 14. Mueller Harvey, I. 1999. Tannins: their nature and biological significance. In Secondary Plant Products, Antinutritional and Beneficia l Actions in Animal Feeding (Caygill, J.C. and Mueller Harvey, I., eds), pp. 17 39, Nottingham University Press Mueller Harvey, I. and A. B. McAllan. 1992. Tannins their biochemistry and nutritional properties. Adv. Plant Cell Bioch. and Biotech 1: 151 2 17. Muir, J. P. 2002. Hand plucked forage yield and quality and seed production from annual and short lived perennial warm season legumes fertilized with composted manure. Crop Sci. 42:897 904. Mupwanga, J. F., N. T. Ngnongoni, J. H. Hopps, and H. Hamudi kuwanda. 2000a. Effects of supplementing a basal diet of Chloris gayana hay with one of three protein rich legume hays of Cassia rotundifolia, Lablab purpureus and Macroptilium atropurpureum forage on some nutritional parameters in goats. Trop. Anim. Healt h Prod. 32:245 256. Murdiati, T. B., C. S. McSweeney, R. S. F. Campbell, and D. S. Stoltz. 1990. Prevention of hydrolyzable tannin toxicity in goats fed Clidemia hirta by calcium hydroxide supplementation. J. Appl. Toxic. 10:325. Narjisse, H., M. A. Elho nsali, and J. D. Olsen. 1995. Effect of oak (Quercus ilex) tannins on digestion and nitrogen balance in sheep and goats. Small Rum. Res. 18:201 206. National Research Council (NRC). 1985. Nutrient Requirements of Sheep, 6th Edition. National Academy Press Washington, DC, 99 pp. National Research Council (NRC) 2007. Nutrient requirements of small ruminants: sheep, goats, cervids and New World camelids. The National Academ y Press, Washington, DC, USA.
107 National Research Council (NRC) 1987. Predicting Fee d Intake of Food Producing Animals. National Academy Press. Washington, D.C. Nauck, M. A, U. Niedereichholz, R. Ettler, J. J. Holst, C. Orkov, R. Ritzel, and W. H. Schmiegel 1997. Glucagon like peptide 1 inhibition of gastric emptying outweighs its insul inotropic effects in healthy humans. Anim. Physiol. Soc. 1997: E981 E988. National Development Agency ( NDA ) 1997. Cultivating Cowpeas. Natl. Dep. Agric., North West Agric. Dev. Inst. Info Park Resource Centre, Mmabatho, Republic of South Africa. Newman Y. C., J. Vendramini, and A. R. Blount. 2010. Minor use summer annual forage legumes. UF/IFAS EDIS pub. no. SS AGR 79. Ngategize, P. K. 1989. Constraint identification and analysis in African small ruminant systems. In. Wilson R T and Azeb M (eds). Afr ican small ruminant research and development. ILCA, Addis Ababa, Ethiopia. Nicholson, T., and S. A. Omer. 1983. The inhibitory effect of intestinall infusion of unsaturated long chain fatty acids on forestomach motility of sheep. Br. J. Nutr 50: 141 149 Niezen, J. H., H. A. Robertson, G. C. Waghorn, and W. A. G. Charleston. 1998. Production, faecal egg counts and worm burdens of ewe lambs which grazed six contrasting forages. Vet. Parasitol. 80: 15 27 Niezen, J. H., T. S. Waghorn, W. A. G. Charleston and G. C. Waghorn. 1995. Growth and gastrointestinal nematode parasitism in lambs grazing either lucerne ( Medicago sativa ) or sulla ( Hedysarum coronarium ) which contains condensed tannins. J. Agric. Sci. 125: 281 289. Njarui, D. M. G, J. G. Mareithi, F. P. Wandera, and R. W. Muinga, 2003. Evaluation of four forage legumes as supplementary feed for Kenya dual purpose goat in the semi arid region of eastern Kenya. Trop. and Subtr. Ago ecosys. 3: 65 71 Noel, R. J., and L. G. Hambleton. 1976. Collaborative study of a semi automated method for determination of crude protein in animal feeds. J. AOAC Int. 59:134 140. Nolan, J. V. 1975. Quantitative models of nitrogen metabolism in sheep. In: McDonald, I. W. and A. C. I. Warner, (Eds.) Digestion and metrabolis m in the ruminant. Pp 416 431. University of New England, Armidale. Oldle, J., and D. M. Schaefer. 1987. Influence of rumen ammonia concentration on the rumen degradation rates of barley and maize. Brit. J. Nutr. 57:127 138.
108 Omokanye, A. T., R. O. Balogu n, O. S. Onifade, R. A. Afolayan, and M. E. Olayemi. 2003. Assessment of preference and intake of browse species by Yankasa sheep at Shika, Nigeria. Small Rumin Res. 42: 201 208. rskov, E. R. 1992. Protein Nutrition in Ruminants. Second ed. Academic Pres s, Inc. San Diego, CA. Ott, J. P., Muir, J. P., Simms, L. 2002. Effect of peanut meal or corn hominy on wethers pastured on coastal fertilized with high or low levels of N. Sheep and Goat, Wool and Mohair Res. Reports. CPR 2002:70 76. San Angelo, TX Ove r, H. J., J. Jansen, and P. W. von Olm. 1992. Distribution and Impact of Helminth Diseases of Livestock in Developing Countries. FAO Animal Production and Health Paper 96. Food and Agriculture Organization (FAO) of the United Nations, Rome, Italy, 221 pp. Owen, F. N, P. Dubeski, and C. F. Hanson. 1993. Factors that alter the growth and performance of ruminants. J. Anim. Sci. 71: 3138 3150. Palmquist, D. L. and T. C. Jenkins, 1980. Fat in lactation rations: Review. J. Dairy Sci. 63:1 14. Paolini, V., A. F rayssines, F. De La Farge, P. Dorchies, and H. Hoste. 2003c. Effects of condensed tannins on established populations and on incoming larvae of Trichostrongylus colubriformis and Teladorsagia circumcincta in goats. Vet. Res. 34: 331 339. Paolini, V., J. P. Bergeaud, C. Grisez, F. Prevot, P. H. Dorchies, and H. Hoste, H., 2003a. Effects of condensed tannins on goats experimentally infected with Haemonchus contortus Vet. Parasitol. 113: 253 261. Paolini, V., P. Dorchies, and H. Hoste. 2003b. Effects of sain foin hay on gastrointestinal nematode infections in goats. Vet. Rec. 152 : 600 601. Papachristoforou, C. and M. Markou, 2006. Overview of the economic and social importance of the livestock sector in Cyprus with particular reference to sheep and goats. Sm all Rum. Res. 62:193 199. Parkins, J. J., and P. H. holmes. 1989. Effects of gastrointestinal helminth parasite s on ruminant nutrition. Nutr Res. Rev. 2: 227 246. Paterson, J. A., R. L. Belyea, J. P. Bowman, M. S. Kerley, and J. E. Williams. 1994. The i mpact of forage quality and supplementation regimen on ruminant animal intake and performance. ln: Forage Quality, Evaluation, and Utilization, Fahey, G.C. Jr (ed.). American Society of Agronomy, Inc., Madison, WI, USA, pp5. 9 11 4.
109 Pathirana, K. K., and E R. rskov. 1995. Effect of supplementing rice straw with urea and glyricidia forage on intake and digestibility by sheep. Livestock Res. Rural Develop. 7: 2. Paulino, M. F., E. Detmann, E. E. Valente, and L. V. Barros. 2008. Nutrio de bovinos em paste jo. In: Proc. 4 th Symposium on Strategic Management of Pasture (Depart. de Zoot. UFV, Viosa, Brazil), 131 169. Payne, W. J. A. and R. T. Wilson, 1999. An introduction to Animal Husbandry in the tropics. Blackwell Science Ltd, pp. 447 484. Peacock, C. 19 96. The feeding habits of goats. Improving goat production in the tropics. A manual for development workers. Oxfam, UK and Ireland., pp 66 68. Peacock, C. P. 2005. Goats A pathway out of poverty. Small Rum. Res. 60: 179 186. Pederson, P. 2004. Soybean growth and development Publ. PM 1945. Iowa State University Extension. Peino, R., R. Baldelli, J. Rodriguez Garcia, S. Rodriguez Garcia, M. Kojima, K. Kkangawa, E. Arvat, E. Ghigo, C. Dieguez, and F. F. Casanueva. 2000. Ghrelin induced growth hormone se cretion in humans. Eur. J. Endocrinol. 143: R11 R14. Pereg, H., K. Gacon, P. Schlich, and A. C. Noble. 1999. Bitterness and astringency of flavan 3 ol monomers, dimers and trimers. J. Sci. Food Agric. 79 1123 1128. Perry, B. D., T. F. Randolph, J. J. Mc Dermott, K. R. Sones, and P. K. Thornton. 2002. Investing in animal health research to alleviate poverty International Livestock Research Institute (ILRI), Nairobi, Kenya, 140 pp. Pinkerton, B., and F. Pinkerton. 1996. Managing Forages for Meat Goats. Me at Goat Production and Marketing Handbook, Rural Economic Development Center, Raleigh, North Carolina and Mid Carolina Council of Governments, Fayetteville, NC. Pinkerton, F. 1995. Meat goat marketing in greater New York City. Final Report of the Center f or Agricultural Development and Entrepreneurship to USDA Agricultural Marketing Service Federal State Market Improvement Program, Washington DC. Pinkerton F., D. Scarfe, and B. Pinkerton. 1991. Meat goat production and marketing. Publication M 01, Langst on University, Langston, Oklahoma, 22 pp. Pinkerton, F., E. N. Escobar, L. Harwell, W. Drinkwater. 1994. A survey of prevalent production and marketing practices in meat goats of southern origin Langston Univ. Goat Res. Ext. Newslett. 182: 1 47.
110 Pinker Publication No. M 03. Langston University: Langston, OK. Poppi, D. P., J. C. MacRae, A. Brewer and R. L. Coop. 1986. Nitrogen transactions in the digestive tract of lambs exposed to the intestinal parasite Triehostrongylus columbriformis Brit. J. Nutr 55:593 602. Poppi, D. P., A. R. Skye and R. A. Dynes. 1990. The effect of endoparasitism on host nutritio n the implications for nutrient manipulation. Proc. N.Z. Soc. Anim. Prod. 50: 237 243 Prichard, R. 1994. Anthelmintic resistance. Vet. Parasitol. 54:259 268. Prins, H. H. T., and J. H. Beekman. 1989. A balanced diet as a goal of grazing: the food of t he Manyara buffalo. African J. ecol. 27: 241 259. Prior, R L., A J. Clifford, D. E. Hogue and WJ. Visek. 1970. Enzymes and metabolites of intermediary metabolism in urea fed sheep. J. Nutr. 100:438 444. P. R. Martin, I. S. Hurwood and P. K. liveweight gain of sheep consuming a mulga ( Acacia aneura ) diet. Proc. Aust. Soc. Anim. Prod. 17:290 293 Provenza, F. D., and J. C. Malechek 1984. Diet selection by domestic goats in relation to blackbrush twig chemistry. J. Appl. Ecol. 21:831 841. Rahman, W. A., and G. H. Collins. 1990. The establishment and development of Haemonchus contortus in goats. Vet. Parasitol. 35: 189 193. Ravhuha li, K. E., J. I. Ayodele. 2011. The feeding value of four cowpea hay cultivars and effects of their supplementation on intake and digestibility of Buffalo grass hay fed to Pedi Goats. Asian J. Anim. and Vet. advances, ISSN 1683 9919 /DOI: 10.3023/java.2012 Accessed 07.2012 Rayburn, E. B. 1986. Quantitative aspect of pasture management. Seneca Trial RC and D Technical Manual. Franklinville, NY. Redmon, L. 2002. Forages for Texas. Texas Cooperative Extension: Texas A&M Univer sity System Soil and Crop Sci. Communications. SCS 2002 14. Overton, TX Reed J. D., H. Soller, and A. Woodward. 1990. Fodder tree and straw diets for sheep: Intake, growth, digestibility and the effects of phenolics on nitrogen utilisation. Anim. Feed Sc i. Technol. 30:39 50
111 Reed, J. D. 1995. Nutritional toxicology of tannins and related polyphenols in forage legumes. J. Anim. Sci. 73: 1516 1528. Reidelberger, R. D. 1994. Cholecystokinin and control of food intake. J. Nutr 124: 1327S 1333S Rhee, K. S. M. Oltman, and J. Han. 2003. Consumer sensory evaluation of plain and seasoned goat meat and beef products. Meat Sci. 65: 785 789. Rinaman, L., G. E. Hoffman, J. Dohanics, W. W. Lee, E. M. Striker, and J. G. Verballs, 1995. Cholecystokinin activates cat echolaminergic neurons in the caudal medulla that innervate the paraventricular nucleus of the hypothalamus in rats. J. Comp. Neurol. 360: 246 256 Roberts, F. H. S., H. N. Turner, and M. McKevett. 1954. On the specific distinctness of the Ovine and bovin e strains of Haemonchus contortus (Rudolphi) Cobb (Nematode: Trichostrondylidae). Aust. J. Zool. 2: 275 295. Robbins, C. T., T. A. Harley, A. E. Hagerman, O. Hjeljord, D. L. Baker, C. C. Schwartz, and W. W. Moutz. 1987. Role of tannins in defending plants against ruminants: Reduction in protein availability. Ecol. 68: 98 107. Roberts, J. L., and R. A. Swan. 1982. Quantitative studies of Ovine haemonchosis. 2. Relationship between total worm count of Haemonchus contortus haemoglobin values and body weight Vet. Parasitol. 9: 201 209 Rose, J. H. 1970. Parasitic gastro enteritis in cattle. Factors influencing the time of increase in worm population of pastures, Res. Vet. Sci. 11: 199 208. Rossanigo, C. E. and L. Gruner. 1995. Moisture and temperature requ irements in faeces for the development of free living stages of gastrointestinal nematodes of sheep, cattle and deer. J. Helminthol. 69: 357 362. Rowe, J. B., J. V. Nolan, G. de Chaneet, E. Teleni, and P. H. Holmes.1988. The effect of haemonchosis and blo od loss into the abomasum on digestion in sheep[ Br J Nutr 59: 125 139 carbohydrate and protein system for evaluating cattle diets: I. Ruminal fermentation. J. An im. Sci. 70:3551 3561. Russell, J. B., C. J. Sniffen, and P. J. Van Soest. 1983. Effect of carbohydrate limitation on degradation and utilization of casein by mixed rumen bacteria. J. Dairy Sci. 66:763 775.
112 Russell, J. B., H. J. Strobel and S. A. Martin 1990. Strategies of nutrient transport by Ruminal bacteria. J. Dairy Sci 73:2996 3012. Sande, D. N., J. E. Houston, and J. E. Epperson. 2005. The relationship of consuming populations to meat goat production in the United States. J. Food Distri. Res. 36:156 160 Santos Buelga, C., and A. Scalbert. 2000. Proanthocyanidins and tannin like compounds nature, occurrence, dietary intake and effects on nutrition and health. J. Sci. Food Agric. 80: 1094 1117. Satter L. D., and L. L. Slyter. 1974. Effect of ammonia concentration on rumen microbial protein production in vitro. Br. J. Nutr. 32:199 208. Sauvant, D., C. Assoumaya, S. Giger Reverdin, and H. Archimde. 2006. tude In : Decruyenaere, V., A. Buldgen and D. Stilmant. 2009. Factors affecting intake by grazing ruminants and related quantification methods: Review. Biotech. Agro. Soc. Environ. 13: 559 573. Schauff, D. J., and J. H. Clark, 1992. Effects of feeding diets conta ining calcium salt long chain fatty acids to lactating dairy cows. J. Dairy Sci. 75:2990 3002 Schofield, P., D. M. Mbugua, and A. N. Pell. 2001. Analysis of condensed tannins: a review. Anim Feed Sci Tech 91 : 21 40. Schwab, C. G. 1995. Protected proteins and amino acids for ruminants. In: Biotechnology in animal feeds and animal feeding (Wallace, R. J. and A. Chesson, eds.). V. C. H. Press, Weinhein (Germany), pp. 115 141. Schwab, C. G. 1996. Amino acid nutrition of the dairy cow. Current status. Proc. C ornell Nutr. Conf., pp. 184 198. Ithaca, NY. Schwartz G. J., T. H. Moran, W. O. White, and E. E. Ladenheim. 1997. Relationship between gastric motility and gastric vagal afferent responses to CCK and GRP in rats differ. Am J Physiol. 272: R1726 R1733 Schwartz, M. W., S. C. Woods, D. Jr. Porte, R. L. Seeley and D. G. Baskin. 2000. Central nervous system control of food intake. Nature 404: 661 671. Scott, L. L. and F. D. Provenza. 1999. Variation in food selection among lambs: effects of basal diet and foods offered in a meal. J. Anim. Sci 77 : 2391 2397. Seeley, R. J., and S. C. Woods. 2003. Monitoring of stored and available fuel by the CNS: inplications for obesity. Nat. Rev. Neurosci. 4: 901 909.
113 Semakula, J., D. Mutetikka, R. D. Kugonza, and D. Mp airwe. 2010. Smallholder goat breeding systems in humid, sub humid and semi arid agro ecological zones of Uganda. Global Vet. 4: 283 291 Shaik, S. A., T. H. Terrill, J. E. Miller, B. Kouakou, G. Kannan, R. M. Kaplan, J. M Burker and J. A. Mosjidis. 2006. Sericea lespedeza hay as a natural deworming agent against gastro intestinal infection in goats. Vet. Parasitol. 139: 150 157 Shaik, S. A., T. H. Terrill, J. E. Miller, B. Kouakou, G. Kannan, R. M. Kaplan, J. M. Burke, and J. A. Mosjidis. 2004. Sericea lespedeza hay as a natural deworming agent against gastrointestinal nematode infection in goats. Vet. Parasitol. 139: 150 157. Sheaffer, C. C., J. H. Orf, T. E. Devine, and J. G. Jewett. 2001. Yield and quality of forage soybean. Agron. J. 93:99 106. She lton, J. M. 1 College Park. Maryland. Shelton, M. 1990. Goat Production in the United States. In: R. C. Gray (Ed.). Proc. Int. Goat Production Symp. Florida A and M Univ., Tallahassee. Sh elton, M., G. Snowder, and E. Figueiredo. 1984. Meat production and carcass characteristics of the goat. SR CRSP Tech. Report Series No. 45. Texas A and M Univ., College Station TX Sheridan, R., L. C. Hoffman, and A. V. Ferreira. 2003. Meat quality of B oer goat kids and Mutton Merino lambs 1. Commercial yields and chemical composition. Anim Sci. 76: 63 71. Shijimaya, K., K. S. Furugouri.and S. Katayama. 1986. Effects of ambient temperature in cold and warm barns in winter on milk production and some ph ysiological responses of Holstein dairy cattle. Jap. J. Zootech. Sci. 57: 479 484 Silanikove, N., N. Gilboa, I. Nir, A. Perevolotsky, and Z. Nitsan. 1996. Effect of a daily supplementation of polyethylene glycol on intake and digestion of tannin containi ng leaves ( Quercus calliprinos, Pistacia lentiscus and Ceratonia siliqua ) by goats. J. Agric. Food. Chem. 44: 199 205. Silanikove, N., Z. Nitsan, and A. Perevolotsky. 1994. Effect of a daily supplementation of polyethylene glycol on intake and digestion of tannin containing leaves ( Ceratonia siliqua ) by sheep. J. Agr. Food Chem. 42: 2844 2847. Silverman, P. H. and J. A. Campbell. 1959. Studies on parasitic worms of sheep in Scotland. I. Embryonic and larval development of Haemonchus contortus at constant conditions. Parasitol. 49: 23 38.
114 Simela, L. and Merkel, R. 2008. The contribution of chevon from Africa to global meat production. Meat Sci 80: 101 109. Sissay, M. M., A. Asefa, A. Uggia, and P.J. Waller. 2006. Anthelmintic resistance of nematode paras ites of small ruminants in eastern Ethiopia: Exploitation of refugia to restore anthelmintic efficacy. Vet Parasitol. 135: 3337 3346. Sissay, M. M., A. Uggla, and P. J. Waller. 2007. Epidemiology and seasonal dynamics of gastrointestinal nematode infecti ons of sheep in a semi arid region of eastern Ethiopia. Vet Pasasitol. 143: 311 321. Smith, G. 1988. The population biology of the parasitic stages of Haemonchus contortus Parasitol. 96:185 195. Solaiman, S. G. 2007. Assessment of the meat goat industr y and future outlook for united states .S. small farms. Tuskegee University. http://www.agmrc.org/media/cms/USGoatProductionFinal_E1367962C32D1.pdf Accessed May, 2011. Solomon, M. R. 1992. Consumer Behavior: Buying, Having and Being. Simon and Schuster, Inc.: Boston. MA. Soulsby, E. J. L. 1982. Helminths, Arthropods and Protozoa of Domesticated Animals. 7th ed. London: Bailliere Tindall. 809 pp. Soulsby, E. J. L. 196 5. Textbook of Veterinary Clinical Parasitology. Vol. I Helminths. Blackwell Scientific Publications Ltd., Oxford, UK pp.1120. Spedding, C. R. W., T. H. Brown, and R. V. Large. 1963. The effect of milk intake on nematode infestation of the lamb. Proc. Nut r. Soc. 22: 32 41. Spencer, C. M., Y. Cai, R. Martin, S. H. Gaffney, P. N. Goulding, D. Magnolato, T. H. Lilley, and E. Haslam. 1988. Polyphenol complexation some thoughts and observations. Phytochem. 27: 2397 2409. Spencer, R. 2008. Overview of the Unit ed States Meat Goat Industry. Publication no. UNP 104. Alabama Cooperative Extension System Stear, M. J., S. C. Bishop, M. Doligalska, J. L. Duncan, P. H. Holmes, J. Irvine, L. McCririe, Q. A. McKellar, E. Sinski, and M. Murray. 1995. Regulation of egg production, worm burden, worm length and worm fecundity by host responses in sheep infected with Ostertagia circumcincta Parasite Immunol. 17: 643 652. Steel, J. W., W. O. Jones, and L. E. A. Symons. 1982. Effects of a concurrent infection of Trichostro ngylus colubriformis on the productivity and physiological and metabolic responses of lambs infected with Ostertagia circumcincta Austr. J. Agri. Res. 33: 131 140.
115 Strain, S. A. J., and M. J. Stear. 2001. The influence of protein supplementation on the immune response to Haemonchus contortus Parasite Immunol. 23: 527 531. Swain, T. 1979. Tannins and lignins. In: Rosenthal, G. A. and Janzen, D. H. (eds.). Herbivores: Their Interaction with Plant Metabolites. Academic Press, New York, USA. pp. 657 682. Sykes, A. R. 1983. Effects of parasitism on metabolism in the sheep. In: The Sheep Production. Nottingham Easter School of Agricultural Science, No 35, pp. 317 334. (W. Haresign. Ed). London: Butterworths. Sykes, A. R. 1994. Parasitism and production in f arm animals. Anim. Prod. 59:155 172. Sykes, A. R. and R. L. Coop. 1976. Intake and utilisation of food by growing lambs with parasitic damage to the small intestine caused by daily dosing with Trichostrongylus colubriformis larvae. J. Agri. Sci. Cambri. 86: 507 515. Sykes, A. R. and R. L. Coop. 1977. Intake and utilization of food by growing sheep with abomasal damage caused by daily dosing with Ostertagia circumchlcta larvae. J. Agri. Sci., Cambri. 88: 671 677. Sykes, A. R., D. P. Poppi and D.C. Elli ot. 1988. Effect of concurrent infection with Ostertagia circumcincta and Trichostrongylus colubriformis on the performance of growing lambs consuming fresh herbage. J. Agric. Sci. Cambridge 110: 531 541. Sykes, A. R., and R. V. Coop. 2001. Interaction b etween nutrition and gastrointestinal parasitism in sheep. N.Z. Vet J. 49: 222 226. Symons, L. E. A. 1985. Anorexia; occurrence, pathophysiology and possible causes in parasitic infection. Adv. Parasitol. 24:103 133. Symons, L. E. A. and D. H. Hennessy. 1981. Cholecystokinin and anorexia in sheep infected by the nematode Trichostrongylus colubri f ormis. Int. J.Parasitol 11: 55 58. Taberlet, P., A. Valentini, H. R. Rezaei, S. Naderi, F. Pompanon, R. Negrini, and P. Ajmone Marsan. 2008. Are cattle, sheep and goats endangered species? Mol. Ecol. 17: 275 284. Journal, Wilmington, DE, 9 February 2004. In : Sande, D. N., J. E. Houston, and J. E. Epperson. 2005. The relationship of co nsuming populations to meat goat production in the United States. J. Food Distri. Res. 36:156 160
116 Takaya, K., H. Ariyasu, N. Kanamoto, H. Iwakura, A. Yoshimoto, M. Harada, K. Mori, Y. Komatsu, T. Usui, A. Shimatsu, Y. Ogawa, K. Hosoda, T. Akamizu, M. Ko jima, K. Kangawa, and K. Nakao. 2000. Ghrelin strongly stimulates growth hormone release in humans. J. Clin. Endocrinol. Metab. 85: 4908 4911 Tanner, G. J., S. Abrahams, and P. J. Larkin. 2000. Biosynthesis of proanthocyanidins (condensed tannin). Aust Centre Agric. Res. Proc. 92: 52 61. Terrill, T. H., G. B. Douglas, A. G. Foote, R. W. Purchas, G. F. Wilson, and T. N. Barry. 1992. Effect of condensed tannins upon body growth, wool growth and rumen metabolism in sheep grazing sulla ( Hedysarum coronari um ) and perennial pasture. J. Agric. Sci. 119: 265 273. Terrill, T. H., G. S. Dykes, S. A. Shaik, J. E. Miller, B. Kouakou, G. Kannan, J. M. Burke and J. A. Mosjidis 2009. Efficacy of sericea lespedeza hay as a natural dewormer in goats: Dose titration s tudy. Vet. Parasitol. 163:52 56. Terrill, T. H., R. M. Kaplan, M. Larsen, O. M. Samples, J. E. Miller, and S. Gelaye. 2001. Anthelmintic resistance on goat farms in Georgia: efficacy of anthelmintics against gastrointestinal nematodes in two selected goat herds. Vet. Parasitol. 97: 261 268. Terrill, T. H., W. R. Windham, C. S. Hoveland, and H. E. Amon. 1989. Forage preservation method influences on tannin concentration, intake, and digestibility of sericea lespedeza by sheep. Agron. J. 81: 435 439. Terr ill, T. H., W. R. Windham, J. J. Evans, and C. S. Hoveland. 1994. Effect of drying method and condensed tannin on detergent fiber analysis of sericea lespedeza. J. Sci. Food and Agric. 66: 337 343. Thompson, D., 2006. Meat goat breeds, breeding management and 4 H market goat management. http://www.extension.umn.edu/meatgoats/components. Accessed 28.09.2012 Tradex AgriSystems Inc. 2009. An analysis of the current goat i ndustry with a focus on Alberta. Alberta Goat Breeders Association Alberta, Canada. Turner, K. E., S. Wildeus, and J. R. Collins. 2005. Intake, performance, and blood parameters in young goats offered high forage diets of lespedeza or alfalfa hay. Small Rumin. Res. 59: 15 23 Uhlinger, C., S. Fleming, and D. Moncol. 1992. Survey for drug resistant gastrointestinal nematodes in 13 commercial sheep flocks. J. Am. Vet. Med. Assoc. 201 : 77 80.
117 United States Development Agency, National Agricultural Statistic s Services (USDA NASS), .2012. Sheep and Goats. Released January 27, 2012 Uriarte, J., and J. Valderrbano. 1990. Grazing management strategies for the control of parasitic diseases in intensive sheep production systems. Vet. Parasitol. 37: 243 255. Urq uhart, G M J. Armour, J. L. Dunca. A. M. Dunn and F. W. Jennings. 2000. Veterinary Parasitology, 2nd Edition. Blackwell Science Ltd. London. Urquhart, G. M., J. L. Armour, J. L. Duncan, A. M. Dunn, and F. W. Jennings. 1996. Page 264 in Veterinary Para sitology. Longman Scientific and Technical Paper. Harlow, UK. Urquhart, G. M., F. W. Jennings, and W. Mulligan. 1966 a Immunity to Haemonchus contortus infection. Failure of X irradiated larvae to immunise young lambs. Am. J. Vet. Res. 27 : 1641 1643. Urq uhart, G. M., W. F. H. Jarrett, F. W. Jennings, W. I. M. Macintyre, and W. Mulligan. 1966 b Immunity to Haemonchus contortus infection. Relationship between age and successful vaccination with irradiated larvae. Am. J. Vet. Res. 27: 1645 1648. USDA NASS. 2011. Overview of the United States Sheep and Goat Industry. htpp://usda.mannlib.cornell.edu.shpGtInd/shpGtInd.08 09 2011.pdf. Accessed 28.09.2012 USDA NASS. 2012. Cattle, Sheep and Goat Inventory. Accessed 15. 01 2012. http://www.nass.usda.gov/Newsroom/Executive_Briefings/2012/01_27_2012.pdf USDA. 1989 Handbook #8. In : McKenzie Jakes, A. 2007. Getting started in the meat goat business; Trends, Developments, Chal lenges and Opportunities in the Meat Goat Industry in Southeastern United States. Florida A&M University, College of Engineering Sciences, Technology, and Agriculture Research and Cooperative Extension Programs,Statewide Goat Program. Bulletin1, vol. 1, pp 1 18 van Houtert, M. F. J. and A. R. Sykes. 1996. Implications of nutrition for the ability of ruminants to withstand gastrointestinal nematode infections. Int J Parasitol.: 26: 1151 1168 Van Soest, P. J. 1965. Symposium on factors influencing the voluntary intake of herbage by ruminants: Voluntary intake in relation to chemical composition and digestibility. J. Anim. Sci. 24: 834 843
118 Van Soest, P. J., J. B. Robertson, and B. A. Lewis. 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. J. Dairy Sci. 74:3583 3597. Van Soest, P. J., 1994. Nutritional Ecology of the Ruminant Second Edition, Cornell University press, Ithaca, NY, 476 pp. Van Wyk, J. A. and G. F. Bath. 2002. The FAM ACHA system for managing hemonchosis in sheep and goats by clinically identifying individual animals for treatment. Vet. Res. 33: 509 529 Van Wyk, J. A. and F. S. Malan. 1988. Resistance of field strains of Haemonchus contortus to ivermectin, closantel, rafoxanide and benzimidazoles in sheep in South Africa. Vet. Rec. 123: 226 228. Van Wyk, J. A., F. S. Malan, and G. F. Bath. 1997b. Rampant anthelmintic resistance in sheep in South Africa. what are the options? In: Van Wyk, J.A. and Van Schalkwyk, P.C. (eds) Proc. Managing Anthelmintic Resistance in Endoparasites. Workshop held at the 16th International Conference of the World Association for the Advancement of Vet Parasitol. 10 15 August 1997, Sun City, South Africa: 51 63. Van Wyk, J. A., F. S. Ma lan, and J. L. Randles. 1997 a How long before resistance makes it impossible to control some field strains of Haemonchus contortus in South Africa with any of the modern anthelmintics?. Vet Parasitol. 70: 111 122. Van Wyk, J. A., F. S. Malan, H. M. Gerb er and R. M. R. Alves. 1987. Two field strains of Haemonchus contortus resistant to rafoxanide. Onderstepoort J. Vet. Res. 54: 143 146. Van Wyk, J. A., M. O. Stenson, J. S. Van der Merwe, R. J. Vorster, and P. G. Viljoen. 1999. Anthelmintic resistance in South Africa : surveys indicate an extremely serious situation in sheep and goat farming. Onderstepoort J. Vet. Res. 66: 273 284. Vatta, A. F., B. A. Letty, M. J. Van der Linde, E. F. Van Wijk, J. W. Hansen, and R.C. Krecek. 2001. Testing for clinical ana emia caused by Haemonchus spp. in goats farmed under resource poor conditions in South Africa using an eye colour chart developed for sheep. Vet. Parasitol. 99:1 14. Vatta, A. F., R. C. Krecek, B. A. Letty, M. J. van der Linde, R. J. Grimbeek, J. F. de Vi lliers, P. W. Motswatswe, G. S. Molebiemang, H.M. Boshoff, and J.W. Hansen. 2002b. Incidence of Haemonchus spp. and effect on haematocrit and eye colour in goats farmed under resource poor conditions in South Africa. Vet. Parasitol. 103 : 119 131.
119 Vatta, A F., R. C. Krecek, J. A. Van Wyk, G. F. Bath, B. A. Letty, M. J. Van der Linde, and H. T. Groeneveld. 1999. Testing a novel technique for the resource poor farmer to manage Haemonchus spp. In : South African Goats Enhanced Research Capacity Workshop. Kenya 24 25, August, 1999 (Abstract) Vatta, A. F., R. C. Krecek, M. J. van der Linde, P. W. Motswatswe, R. J. Grimbeek, E. F. van Wijk, and J. W. Hansen. 2002a. Haemonchus spp. in sheep farmed under resource poor conditions in South Africa effect on haemat ocrit, conjunctival mucous membrane colour and body condition. J. S. Afr. Vet. Assoc. 73: 119 123. Veglia, F., 1915. The anatomy and life history of the Haemonchus contortus (Rud.). Rep. Vet. Res. S. Afr. 3: 349 500. Vitousek, P. M., J. Aber, R. W. Howar th, G. E. Likens, P. A. Matson, D. W. Schindler, W. H. Schlesinger, and G. D. Tilman. 1997. Human alteration of the global nitrogen cycle: Causes and consequences. Ecolog. Applic. 7: 737 750. Waghorn, G. C. 1990. Beneficial effects of low concentrations o f condensed tannins in forages fed to ruminants. Pages 137 147 I n : Akin D. E. L. G. Ljungdahl, J. R. Wilson, and P. J. Harris ( eds ) Microbial and plant opportunities to improve lignocellulose utilization by ruminants. Elsevier Science Publishing Co., Ne w York, NY. Waghorn, G. C., A. John, W.T. Jones and I.D. Shelton. 1987a. Nutritive value of Lotus corniculatus L. containing low and medium concentrations of condensed tannins for sheep. Proc. N. Z. Soc. Anim. Prod. 47: 25 30. Waghorn, G. C., and W. C. M cNabb. 2003. Consequences of plant phenolic compounds for productivity and health of ruminants. Proc Nutrition Society 62: 383 392. Waghorn, G. C., I. D. Shelton and W. C. McNabb. 1994. Effects of condensed tannins in L. pendunculatus on its nutritive va lue for sheep. 1 Nitrogenous aspect. J. Agri. Sci., Cambri. 123: 99 107. Waghorn, G. C., Shelton, I. D. and McNabb, W.C. 1994a. Effects of condensed tannins in Lotus pedunculatus on its nutritive value for sheep. 1. Non nitrogenous aspects. J. Agri. Sci. Cambridge 123: 99 107. Waghorn, G C I. D. Shelton, W. C. McNabb and S. H. McCutcheon. 1994. Effects of condensed tannins in Lotus pedunculatus on its nutritive value for sheep. 2. Nitrogenous aspects. J. Agri. Sci. Cambridge 123 : 109 119. Waldo, D. R 1986. Effect of forage quality on intake and forage concentrate interactions. J. Dairy Sci. 69:617.
120 Wallace, D. S., K. Bairden, J. L. Duncan, G. Fishwick, M. Gill, P. H. Holmes, Q. A. McKellar, M. Murray, J. J. Parkins, and M. J. Stear. 1996. Influenc e of soyabean meal supplementation on the resistance of Scottish blackface lambs to haemonchosis. Res Vet. Sci. 60: 138 143. Waller, P. J. 1994. The development of anthelmintic resistance in ruminant livestock. Acta Trop. 56:233 243. Waller, P. J. 1997. Anthelmintic resistance Vet. Parasitol. 72: 391 412. Waller, P. J. and P. Chandrawathani. 2005. Haemonchus contortus : parasite problem No. 1 from tropics polar circle. Problems and prospects for control based on epidemiology. Trop. Biomed. 22: 131 137 Wang, Y., G. C. Waghorn, G. B. Douglas, T. N. Barry, and G. F. Wilson. 1994. The effects of the condensed tannin in Lotus corniculatus upon nutrient metabolism and upon body and wool growth in grazing sheep. Proc N Z Soc Anim Prod 54: 219 222. Wa terman, P. G. 2000. The tannins an overview. Australian Centre for Int. Agr i c. Res. Proc. 92: 10 13. Watson, T. G. and B. C. Hosking. 1990. Evidence for multiple anthelmintic resistance in two nematode parasite genera on a Saanen goat dairy. N. Z. Vet. J. 38: 50 53. Whitlock, H. V. 1948. Some mopdifications of the McMaster helminths egg counting technique apparatus. J. Counc Sci. Ind. Res. 21: 177 180. Wiederholt, R., and K. Albrecht. 2003. Using soybean as forage. Focus on forage 5: 1 2. Available on line at www.uwex,edu/ces/crops/uwforage/soybeanForageFOF,pdf Accessed 16.08.2012. Wiegand, R. O., J. D. Reed A. N. Said and V. N. Ummuna. 1995. Proanthocyanidins (condensed tan nins) and the use of leaves from Sesbania sesban and Sesbania goetzei as protein supplements. Anim. Feed Sci. and Technol 54: 175 192. Wiegand, R. O., J. D. Reed, D. K. Combs, and A. N. Said, 1996. Leaves from tropical trees as protein supplements in die ts for sheep. Trop. Agric ., 73: 62 68. Williams, M. J., and A. C. Hammond. 1999. Rotational vs continuous intensive stocking management of bahiagrass for cows and calves. Agron. J. 91:11 16 Wolfe, R. M., T. H. Terrill, and J. P. Muir. 2008. Season and d rying method effects on condensed tannin levels in perennial herbaceous legumes. J. Sci. Food Agric. 88: 1060 1067.
121 Woods, S. C. 2004. Gastrointestinal satiety signals I. An overview of gastrointestinal signals that influence food intake. Am J. Physiol. 2 86: G7 G13. Woods, S. C., M.W. Schwartz, D. G. Baskin, and R. J. Seeley. 2000. Food intake and the regulation of body weight. Ann. Rev. Psycho. 51: 255 277. Woods, S. C., R. J. Seeley, D. J. Porte, and M. W. Schwartz. 1998. Signals that regulate feed in take and energy homeostasis. Sci. 280: 1378 1383. Workneh, A. 2000. Do smallholder farmers benefit more from crossbred (Somali x Anglo Nubian) than from indigenous goats? Ph D Thesis. Georg August University of Goettingen, Goettingen, Germany. Cuvillier Verlag, Goettingen. Young, B. A. 1988. Effect of environmental stress on nutrient needs. pp. 456 467. In D. C. Church (Ed). The Ruminant Animal: Digestive Physiology and Nutrition. Waveland Press, Inc., Prospect Heights, IL. Yu, F., L. A. Bruce, A. G. Ca lder, E. Milne, R. L. Coop, G. W. horgan, and J. C. MacRae. 2000. Subclinical infection with the nematode Trichostrongylus colubriformis increases gastrointestinal tract leucine metabolism and reduces availability of leucine for other tissues. J. Anim. Sci 78: 380 390 Zajac A. M., and T. A. Gipson 2000. Multiple anthelmintic resistance in a goat herd. Vet. Parasitol. 87 : 163 172. Zarate, M. U. 2012. Effects of supplementation with tropical plants on the performance and parasite burden of goats. M.S. the sis University of Florida Gainesville, FL. Zucker, W. V. 1983. Tannins: does structure determine function? An ecological perspective. Am Nat 121 : 335 365.
122 BIOGRAPHICAL SKETCH Born in Mzimba district (Malawi), Hamie Joseph Chakana is the second c hild of Bennet Mzomera Hamie and Angerine Soko. He received the Malawi School Certificate of Education ( Ordinary level equivalent) at Robert Laws Secondary School Mzimba from 1994 1998. In May 1999 he was admitted to Bunda C ollege of Agriculture, a con stituent c ollege of the University of Malawi. In May 2003, he graduated with the degree of Bachelor of Science (BS c ) in a griculture with specialization in c rop s cience. Shortly after graduating (June 2003), he was employed as an Agricultural Research Scien tist with the Ministry of Agriculture, Irrigation and Water Development in the Department of Agricultural Research Services (DARS) and was based at Chitala Agricultural Research S tation in Salima. He was attached to the Livestock and Pastures Research Team to develop pasture production and management technologies and information and services for use by livestock farmers and stakeholders. In 2007, he was promoted to the post of Principal Agricultural Research Scientist. He has held several administrative posts such as Station Manager for Research S tations and Acting National Research Coordinator for the Livestock and Pastures Re search P rograms. Through financial support from the United Tates Agency for International Devel opment ( USAID ) Initiative for Long Tern Training and Capacity Building (UILTCB) program and the Malawi Government, Joseph was admited to the University of Florida to pursue a M aster of S cience (M S ) degree program under th e supervision of Prof. Adegbola T Adesogan in the Department of Animal Sciences. At the University of Florida he was privileged to learn the principles and practices of animal welfare, husbandry, production and management from seasoned p rofessors, technical staff and
123 other students. He i s glad to present the results of his research in this thesis as part of the requirements of the M aster of S c ien c e program.