Title: Digestibility and net energy studies with bird-resistant sorghum grain diets fed to steers
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Title: Digestibility and net energy studies with bird-resistant sorghum grain diets fed to steers
Physical Description: 57 leaves : ; 28 cm.
Language: English
Creator: Maxson, William Edwin, 1947-
Copyright Date: 1973
 Subjects
Subject: Cattle -- Feeding and feeds   ( lcsh )
Sorghum as feed   ( lcsh )
Animal Science thesis Ph. D
Dissertations, Academic -- Animal Science -- UF
Genre: bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by William Edwin Maxson.
Bibliography: Bibliography: leaves 50-56.
General Note: Thesis (Ph. D.)--University of Florida, 1973.
General Note: Vita.
General Note: Typescript.
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Bibliographic ID: UF00098187
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
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Resource Identifier: alephbibnum - 000410331
oclc - 24664301
notis - ACF7099

Full Text













DIGESTIBILITY AND NET ENERGY STUDIES WITH
BIRD-RESISTANT SORGHUM GRAIN DIETS FED TO STEERS





By



WILLIAM EDWIN MAXSON


A DISSERTATION PRESENTED TO THE GRADUATE
COUNCIL OF THE UNIVERSITY OF FLORIDA IN PARTIAL
FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE
OF DOCTOR OF PHILOSOPHY


UNIVERSITY OF FLORIDA
1973





















UNIVERSITY OF FLORIDA
l122 0866 2II IIIH
S 3 1262 08666 211 0































DEDICATION

To my wife, Joann, for her understanding and encouragement

during this period of academic endeavor.









ACKNOWLEDGEMENTS

The author wishes to express his sincere gratitude to Dr. R. L.

Shirley, Chairman of his graduate committee, for his guidance,

patience, and understanding throughout this doctoral program and

the preparation of this dissertation.

The author would also like to thank Dr. T. J. Cunha, Dr. C. B.

Ammerman, Dr. J. E. Bertrand, Dr. E. M. Hoffman, Dr. R. H. Houser and

Dr. A. Z. Palmer for serving on his graduate committee. The writer is

especially indebted to Mr. J. Scott for the assistance he gave in

collecting the carcass data and Dr. D. E. Franke for his assistance in

the statistical analysis.

He is grateful for the assistance given him by many of the graduate

students, staff, and personnel of the Nutrition Laboratory.








TABLE OF CONTENTS

Page

ACKNOWLEDGEMENTS . . . . . . . . ... .. ill

LIST OF TABLES . . . . . . . . . . v

LIST OF FIGURES . . . . . . . . .. . vii

ABSTRACT . . . . . . . . ... . . . viii

INTRODUCTION . . . . . . . ... .... 1

LITERATURE REVIEW . . . . . . . .... ... 3

Feeding Value of Sorghum Grain . . . . . 3

Bentonlte . . . . . . . . ... . . 8

Soft Phosphate . . . . . . . . .. ... 10

California Net Energy System . . . . . .. 11

EXPERIMENTAL PROCEDURE . . . . . . . .... 15

Experiment I . . . . . . . .... . 15

Experiment II . . . . . . . . ... 18

RESULTS AND DISCUSSION . . . . . . . .... 26

Experiment I . . . . . . . .... . 26

Experiment II . . . . . . . .... . 28

SUMMARY . . . . . . . . . . .... 41

APPENDIX . . . . . . . ... .... . 43

LITERATURE CITED . . . . . . . . ... . 50

BIOGRAPHICAL SKETCH . . . . . . . . .. 57









LIST OF TABLES


Table Page

1. EXPERIMENTAL DESIGN OF METABOLISM TRIAL WITH
STEERS FED SORGHUM GRAIN DIETS CONTAINING ADDED
BENTONITE OR SOFT PHOSPHATE . . . . .... 16

2. INGREDIENTS OF SORGHUM GRAIN DIETS WITH ADDED
BENTONITE OR SOFT PHOSPHATE FED TO STEERS DURING
METABOLISM TRIAL, AS FED BASIS . . . . .. 17

3. COMPOSITION OF SORGHUM GRAIN DIETS CONTAINING
ADDED BENTONITE OR SOFT PHOSPHATE FED TO STEERS
DURING METABOLISM TRIAL, DRY MATTER BASIS . . .. .19

4. EXPERIMENTAL DESIGN OF METABOLISM PHASE OF NET
ENERGY STUDY WITH STEERS FED CORN, NON-BIRD-
RESISTANT, OR BIRD-RESISTANT SORGHUM GRAIN DIETS .20

5. INGREDIENTS OF CORN, NON-BIRD-RESISTANT AND BIRD-
RESISTANT SORGHUM GRAIN DIETS FED TO STEERS IN
METABOLISM AND FEEDLOT PHASES OF NET ENERGY
DETERMINATION, AS FED BASIS . . . . .... 22

6. EXPERIMENTAL DESIGN OF CORN, NON-BIRD-RESISTANT
AND BIRD-RESISTANT SORGHUM GRAIN DIETARY TREAT-
MENTS FOR STEERS DURING FEEDLOT PHASE OF NET
ENERGY STUDY. . . . . . . .. . . 23

7. COMPOSITION OF CORN, NON-BIRD-RESISTANT AND
BIRD-RESISTANT SORGHUM GRAIN DIETS FED TO STEERS
IN METABOLISM AND FEEDLOT PHASES OF NET ENERGY
DETERMINATION, DRY MATTER BASIS . . . ... 25

8. PERCENT DIGESTION OF DRY MATTER, ORGANIC MATTER,
ETHER EXTRACT, FIBER, NITROGEN, NITROGEN-FREE-
EXTRACT, APPARENT ASH ABSORPTION AND TOTAL
DIGESTIBLE NUTRIENTS IN METABOLISM TRIAL WITH
SORGHUM GRAIN DIETS CONTAINING ADDED BENTONITE
OR SOFT PHOSPHATE . . . . . . .... 27

9. PERCENT TANNINS IN FECES AND URINE, NITROGEN
RETENTION, PERCENT ENERGY DIGESTED, DETERMINED
METABOLIZABLE ENERGY AND CALCULATED METABOLIZABLE
ENERGY FROM METABOLISM TRIAL WITH SORGHUM GRAIN
DIETS CONTAINING ADDED BENTONITE AND SOFT
PHOSPHATE FED STEERS . . . . ... ... . . 29






Table Page

10. PERCENT DIGESTION OF DRY MATTER, ORGANIC MATTER,
ETHER EXTRACT, FIBER, NITROGEN, NITROGEN-FREE-
EXTRACT, NITROGEN RETENTION OR APPARENT ASH
ABSORPTION IN CORN, NON-BIRD-RESISTANT AND BIRD-
RESISTANT SORGHUM GRAIN DIETS FED STEERS DURING
METABOLISM PHASE OF NET ENERGY DETERMINATION . .. 30

11. DIGESTIBLE ENERGY, TOTAL DIGESTIBLE NUTRIENTS,
DETERMINED METABOLIZABLE ENERGY AND CALCULATED
METABOLIZABLE ENERGY IN CORN, NON-BIRD-RESISTANT
AND BIRD-RESISTANT SORGHUM GRAIN DIETS FED STEERS
DURING METABOLISM ENERGY TRIAL PHASE OF NET ENERGY
DETERMINATION . . . . . . . .... . .32

12. PERFORMANCE OF STEERS FED CORN, NON-BIRD-RESISTANT
OR BIRD-RESISTANT SORGHUM GRAIN DIETS DURING FEED-
LOT PHASE OF NET ENERGY DETERMINATION . . ... 33

13. NET ENERGY FOR MAINTENANCE AND NET ENERGY FOR
GAIN VALUES FOR CORN, NON-BIRD-RESISTANT AND
BIRD-RESISTANT SORGHUM GRAIN DIETS .. . . ... .37

14. ACTUAL COMPARED TO PREDICTED BODY WEIGHT GAINS
CALCULATED WITH BLAXTER'S METABOLIZABLE ENERGY
EQUATIONS AND THE NRC ENERGY FOR MAINTENANCE AND
GAIN VALUES OF STEERS FED CORN, NON-BIRD-
RESISTANT AND BIRD-RESISTANT SORGHUM GRAIN DIETS .. 40

15. RATE OF GAIN, DRY MATTER CONSUMPTION AND FEED
EFFICIENCY DETERMINED FROM CATTLE FED CORN, NON-
BIRD-RESISTANT OR BIRD-RESISTANT SORGHUM GRAIN
DIETS DURING FEEDLOT PHASE OF NET ENERGY
DETERMINATION . . . . . . . ... . 44

16. CARCASS SPECIFIC GRAVITY, BODY SPECIFIC GRAVITY,
BODY WATER, BODY FAT, AND BODY PROTEIN DETERMINED
FROM STEERS FED CORN, NON-BIRD-RESISTANT OR BIRD-
RESISTANT SORGHUM GRAIN DIETS DURING NET ENERGY
STUDY . . . . . . . . . . . . .46








LIST OF FIGURES

Figure Page

1. VALUES OBTAINED IN THE PRESENT STUDY PLOTTED ALONGSIDE
THE GRAPHIC LINE PUBLISHED BY LOFGREEN AND GARRETT . . .. .35






Abstract of Dissertetion Presented to the
Graduate Council of the University of Florida
in Partial Fulfillment of the
Requirements for.the Degree of Doctor of Philosophy



DIGESTIBILITY AND NET ENERGY STUDIES WITH
BIRD-RESISTANT SORGHUM GRAIN DIETS FED TO STEERS

By

William Edwin Maxson

March, 1973



Chairman: Dr. R. L. Shirley
Major Department: Animal Science

Two experiments were conducted on utilization of nutrients in

sorghum grain diets with steers. In one of the experiments the

digestibility of nutrients was determined with six crossbred, Hereford

X Angus steers using a 3 X 3 crossover Latin square design trial in

which dietary treatments were bird-resistant sorghum grain diets, with

and without added bentonite or soft phosphate. Addition of 2% bentonite

or 1% soft phosphate to the diet had no significant effect on digestion

of dry matter, organic matter, fiber, nitrogen-free-extract or total

digestible nutrients. Digestion of nitrogen and apparent ash absorption

were decreased (P < .01) when 2% bentonite was added. Addition of 1%

soft phosphate decreased ether extract digestion (P < .05). Digestion

or urinary excretion of dietary tannins was not affected by the additions

of bentonite or soft phosphate to the diets.

The second experiment investigated the utilization of energy in

sorghum grain and corn diets by steers. This involved metabolism and

feedlot phases. In the metabolism phase three Angus steers were

randomly assigned to a 3 X 3 Latin square trial to determine the

vili





metabolizable energy and digestibility of other nutrients of corn,

non-bird-resistant and bird-resistant sorghum grain diets. The corn

diet contained more digestible dry matter, organic matter, nitrogen,

nitrogen-free-extract, energy, metabolizable energy and total digestible

nutrients than either of the two types of sorghum grain diets. The

non-bird-resistant sorghum grain diet contained slightly more digestible

dietary nutrients than the bird-resistant sorghum grain diet.

The feedlot trial involved 48 steers equally assigned to six

treatment groups. They were fed the diets described above at limited

and ad libitum levels of intake. The corn diet produced more live

weight gain on less feed than either sorghum grain diet. Steers fed

the non-bird-resistant sorghum grain diet gained slightly faster and

consumed less dry matter than those fed the bird-resistant sorghum

grain diets.

Using data from both the metabolism and feedlot trials the net

energy for maintenance values of the corn, non-bird-resistant and bird-

resistant sorghum grain diets was 1.67, 1.41 and 1.35 Mcal per kg of

diet, respectively.

Metabolizable energy calculated by multiplying the NRC factor

times the total digestible nutrients gave values within 5% of those

actually determined. Blaxter's metabolizable energy system and the

net energy for maintenance and gain values in tables in the NRC

Bulletin on Nutrient Requirements of Beef Cattle were compared in

regard to predicting live weight gains. Both systems gave values

for predicted gains that were within 0.1 kg per day of the actual

values obtained by the steers fed the corn diet ad libitum. The NRC

system was closer to the actual gain values for the non-bird-resistant

sorghum grain diet while values by Blaxter's system were closer with





the bird-resistant sorghum grain diet. The NRC system was consistently

closer to the actual values from the feedlot data with all limited-fed

dietary groups than Blaxter's system. From an overall view of the data

the NRC system should probably be considered the better of the two

systems.








INTRODUCTION

It should greatly aid the cattle feedlot Industry in Florida to

succeed if new high quality energy feeds were produced in the state.

Sorghum grain is a prospective high energy feed. Several problems

such as bird damage and variability in feeding value of the sorghum

grains have detracted from their widespread acceptance In comparison

to corn. Plant geneticists have worked for many years to develop high

yielding types of sorghum grain that are bird-resistant. At the present

time several bird-resistant types are being grown in the United States.

These new types of sorghum grains appear to be suited to Florida since

they have produced as much or more tonnage of grain per acre during dry

years than corn or non-bird-resistant types.

Variability in feeding quality is characteristic of sorghum grain

and has been shown to exist widely throughout the United States (Hale

et al., 1968, from Arizona; McGinty'and Riggs, 1968, from Texas; and

Bertrand and Lutrick, 1971, from Florida). Variability may range In

digestibility of the amino acids from 60 to 80% as reported by Henderson

and Breuer (1969). Rate of gain data has shown the bird-resistant types

to be inferior to the non-bird-resistant sorghum grain when fed to

cattle (Anonymous, 1969; and Bertrand and Lutrick, 1971). In order that

Florida-grown sorghum grains be fed most efficiently, the feeding values

of different genetic types need to be determined.

The cattle feeder of Florida should benefit most if the feeding

quality of locally produced sorghum grains was determined with the type

of cattle and conditions that exist in Florida. The net energy for








2

maintenance and net energy for gain values of Florida-produced sorghum

grains especially need to be evaluated. Some livestock producers

question if the types of sorghum grains grown in the state have feeding

values comparable to those used as guidelines in the Bulletin on

Nutrient Requirements of Beef Cattle (NRC, 1970). Since most feeders

are familiar with total digestible nutrients (TDN) rather than net

energy, both TDN and net energy values need to be obtained so the

cattle feeders can compare them.

Metabolizable energy has been used to predict gains in growing

finishing cattle by Blaxter (1962). Since it is easier to obtain

metabolizable energy values for a ration than net energy values,

work needs to be done to evaluate the two systems as to their accuracy

at predicting gains for cattle.

The present Investigation was carried out to evaluate sorghum

grain diets in regard to digestible nutrients, feedlot performance, net

energy for maintenance and weight gains. Comparisons of the net energy

system versus the Blaxter metabolizable energy system for predicting

gains were carried out. The metabolizable energy value was also

compared to a calculated metabolizable energy value based on the total

digestible nutrients of the diet, using the National Research Council

factor (NRC, 1970).








LITERATURE REVIEW

Sorghum grain has been fed to livestock and poultry with variable

results and generally with less success than corn diets. The present

review primarily covers that portion of the literature that pertains

to the nutritive value of sorghum grains for ruminant animals.


Feeding Value of Sorghum Grain

Determinations of the nutrient availability of sorghum grain has

demonstrated that many factors may affect Its quality as a feed for

ruminants. One such factor is the variety. There are numerous varieties

of sorghum grain and frequently this information is not reported in experi-

mental feeding trials. Cardon (1964) reported that sorghum grain varieties

may vary in protein from 8.4 to 11.9% and starch from 67.9 to 76.5%. Eng

et al. (1965) observed protein values ranging from 9.3 to 14.0% with

digestibilities of 62.1 to 78.6% when several sorghum grains were tested.:

McGinty and Riggs (1968) reported protein digestibility to range from 23.4

to 54.4% with eight different varieties of Texas sorghum grain. 'Protein,

digestibility data have been associated with location by variety interaction

(Driedger and Riggs, 1972) and amount of nitrogen fertilization (Eng et al.,

1965). Henderson and Breuer (1969) reported that the digestibility of the

individual amino acids of sorghum grain may vary from 60 to 80%. Dry

matter digestibility varied among 61 varieties of sorghum grain from 43.7

to 137.0% when corn was used as a standard (Samford et al., 19704. The

ash fraction varies in concentration significantly as reported by Furr and

Sherrod (1968). These workers reported an average content of calcium,








phosphorus, magnesium, potassium, sulfur, copper, iron, manganese, zinc

and molybdenum in 132 train loads of sorghum grain to be 0.06%, 0.44%,

0.15%, 0.48%, 0.09%, 5.7 ppm, 52.8 ppm, 21.2 ppm, 26.4 ppm, and 0.6 ppm,

respectively.

Investigators have classified sorghum grain according to the sorghum

endosperm type. Sherrod, Albin and Furr (1969) classified sorghum grain

into regular and waxy types. Approximately 100% of the starch contained

in the waxy type is amylopectin while the starch of the regular type is

75% amylopectin and 25% amylose. These authors reported that waxy sorghum

grain contains more net energy for maintenance and production than does the

regular type of sorghum grain. When sheep were fed waxy or regular types

of sorghum grain, Sherrod and Furr (1970) reported no differences in their

digestibilities. This supported results reported by Nishimuta, Sherrod

and Furr (1969) in which there was no significant difference in the digesti-

bility of the regular or waxy types of grain sorghum when fed to sheep.

Samford et al. (1970b)classified sorghum grain endosperm types into floury,

waxy, normal, and corneous, depending on the sorghum's starch granules,

and reported carbohydrate digestibility percentages of 80.1, 75.0, 68.1,

and 48.4, respectively. The normal type in this trial is similar to the

regular type In the above experiments by Sherrod et al. (1969).

A broad category of sorghum grain classification is bird-resistant

and non-bird-resistant types. Rate of gain and feed efficiency of the

bird-resistant type was observed to be lower with steers than that of the

non-bird-resistant type (Bertrand and Lutrick, 1971). Withers et al:,

(1969) and Pund (1970) reported that silage from non-bird-resistant

sorghum is utilized more efficiently than silage from the bird-resistant

type. When starch digestibility was compared in the two types of sorghum






5

grain the starch in the non-bird-resistant type was more available than

in the bird-resistant type (Hinders and Eng, 1971). An extensive study

was conducted by McGinty, Riggs and Kunkel (1969) to determine the

digestibility of bird-resistant and non-bird-resistant sorghum grain,

in vitro. The non-bird-resistant type supported greater bacterial

activity. The pericarp and endosperms of the two varieties were separated

and placed in separate fermentation tubes. The endosperms of the two

;varieties supported in vitro gas production equally. But the pericarps of

the bird-resistant type supported significantly less gas production when

mixed with either endosperm. These workers concluded that the tannin

contained in the seed coat of the bird-resistant sorghum grain was likely

the cause of the decreased digestion.

To improve the feeding value of sorghum grain investigators have

tried various processing techniques. One of the most popular processing

techniques is steam flaking. Kuhlman et al. (1968) reported significant

Increases in weight gains and feed efficiency of cattle fed steam flaked

compared to dry rolled sorghum grain. Steam flaking and pressure cooking

was shown to result in greater digestibility when compared to dry rolling,

steam cut, water soaked cut, and fine ground sorghum grain (Husted et al.,

1968). Holmes, Drennan and Garrett (1970) reported that when pressure was

increased from 0 to 3.5 kg per cm2 during cooking that there was no

difference in the digestibility of starch or the rate of gain for ruminants.

Schuh, Hale and Theurer (1971) also reported that pressure cooking gave

similar results in comparison to steam processing or flaking when fed to

dairy calves.

Another popular method for processing sorghum grain is reconstituting

the grain with water and storing it in air-tight containers. Neuhaus and








Totusek (1971) reported that the moisture level for the greatest

digestibility of sorghum grain is 36%. Feedlot trials have shown that

cattle fed high moisture sorghum grain tend to consume less dry matter.

daily but utilize it more efficiently than cattle fed air dried grain

(Brethour and Duitsman, 1961; Newsom et al., 1968; Riggs and McGinty,

1970; and Kiesling, McCroskey and Wagner, 1971). Buchanan-Smith, Totusek

and Tillman (1968) and Eudaly and Riggs (1969) reported that dry matter

digestibility of steam-rolled sorghum grain is not significantly greater

than dry matter digestibility for reconstituted grain. McNeill, Potter

and Riggs (1971) reported that starch and protein digestion was increased

in sorghum grain by reconstituting compared to steam flaking (Potter,

McNeill and Riggs, 1971). In vitro digestibility of reconstituted sorghum

grain was increased when acetic acid, metaphosphoric acid or sodium hydride

was added to the water used for reconstitution (Lane, Leighton and Bade,

1972).

One of the newest methods for processing sorghum grain is popping.

Popping results in decreased feed intake as stated by Ellis and Carpenter

(1966) and Riggs et al. (1970). These authors reported that although the

feed intake was decreased the efficiency of utilization was increased. In

a rate of gain trial with feedlot cattle there was no statistical.difference

between diets of popped, flaked or cracked sorghum grain (Durham, Ellis and

Cude, 1967).

Sorghum grain has been compared with many other concentrates as a

livestock feed. Tommeroik and Waldern (1969) reported no differences in

milk production when cows were fed either wheat, corn, barley, oats, or

sorghum grain. Similar results were obtained by Franks et al. (1972)

when no differences In rate of gain or feed efficiency with feedlot cattle






7

occurred upon comparing barley, oats, corn or sorghum grain. Sorghum

grain is considered to be quite similar in feeding value for dairy cows

(Brown et al;, 1966) and fattening steers (Ralston et al., 1963, and Hale

et al., 1966) when compared to barley. Garrett, Lofgreen and Meyers (1964)

and Garrett (1965) reported no significant differences in the net energy

of .barley or sorghum grain when fed to feedlot cattle. Dry matter has

been reported to be more digestible in barley than in sorghum grain (Saba

et al., 1964). The starch of barley has been observed to be utilized more

efficiently than the starch in sorghum grain (Cadena et al., 1962, and Osman

et al., 1970). Taylor et al. (1960) obtained increased rate of gain and

feed utilization when cattle were fed barley compared to sorghum grain.

Sorghum grain was superior to barley in both digestibility and feedlot

performance of cattle according to Keating et al. (1965). Brown et al.

(1970) demonstrated that sorghum grain was superior to barley when milk

fat production of dairy cows was the test criterion.

Variability in feeding value of sorghum grain became apparent when

research comparing sorghum and corn was reviewed. Sorghum grain diets were

reported equal to corn diets in digestibility, energy and nitrogen retention

for cattle (Brown, Tillman and Totusek, 1968). Hall et al. (1968) state:

that there is no reason for cattle feeders to discriminate against sorghum

grain as an energy source when it is fed with balanced minerals, vitamins

and protein. These authors based their statement on their research showing

corn and sorghum grain equal in net energy. However, they pointed out that

variation among sorghum types could affect its feeding value. Fox et al.

(1970) reported more net energy in corn grain and silage than in either

sorghum grain or silage. Gross energy, digestibility or protein, ether

extract, nitrogen-free-extract, and dry matter were reported higher for





8

corn than sorghum grain (McCollough et al., 1972). In feedlot trials

Bertrand, Dunavin and Lutrick (1970) and McCollough et al. (1972) have

shown corn to be slightly superior in producing increased rate of gain

than sorghum grain. These authors reported that feed efficiency was

better with corn. Newland,Klosterman and Fox (1970) reported corn rations

produced gains significantly faster than bird-resistant sorghum grain

rations.


Bentonite

Bentonite is a clay consisting primarily of montmorillonite.

Montmorillonite has the approximate chemical formula:

(Al,Fe.67Mg3) Sl010 (OH)2 Na, Ca33

Approximately 10% of bentonite consists of small fragments of other

minerals, the most abundant being feldspar (Martin, 1967).

In the wine industry, bentonite is used to precipitate tannins

(Deis and Sanchez, 1964). Work by Filippov and Valuiko (1970) and

Valuiko and Ivanyutina (1970) obtained similar results demonstrating

that bentonite precipitated tannins. Bentonite has been used as an

additive to livestock and poultry feeds in the United States for several

years, generally because of its binding property for pelleted feeds.

Addition of bentonite to diets may cause problems with animals under

certain conditions. Vitamin A deficiency was produced with chickens

when Brlggs and Fox (1956) fed 2 or 3% of sodium or calcium bentonite.

The vitamin A source used in their study was unstabilized and the deficiency

probably would not have occurred if stabilized vitamin A had been fed.

Bentonite has been used to isolate vitamin B12 from biological samples

followed by elution of the vitamin prior to analysis (Popova, 1962). It

is believed that the capacity of bentonite to absorb and exchange many






9

substances may at times decrease excesses of toxic materials, but at

times may decrease availability of nutrients that are already at low

concentrations.

Bentonite has been fed to ruminants without detrimental effects

(Erwin et al., 1957; Hillis, 1968; and Mendel, 1971). In the dairy

industry bentonite is added to high energy rations to counteract the

decrease in the milk fat percentage that characteristically occurs with

such diets (Bringe and Schultz, 1969; Rindsig, Schultz and Shook, 1969;

Rindslg and Schultz, 1970). Rindsig and Schultz (1970) found that the

addition of 5 or 10% bentonite to high grain diets decreased significantly

dry matter and nitrogen digestibility by lactating dairy cows. In work

done with sheep fed a high roughage ration the addition of 2 to 8% bentonite

did not significantly decrease dry matter digestibility; however, at 2% of

the diet it slightly increased nitrogen retention (Martin, Clifford and

TIllman, 1969).

When bentonite was added to feedlot type diets that contain urea

Inconsistent results have been obtained. Vetter, Gay and Ransom (1967)

found that 150 g of bentonite consumed per day by steers fed feedlot

type diets resulted in an increase in weight gain and feed consumption.

However, subsequent studies (Vetter et al., 1968; Perry et al., 1968)

Indicated that the bentonite was without effect. Using feedlot diets

containing urea, data was obtained that demonstrated that the addition

of 2% bentonite Increased daily gain 86 grams (Anonymous, 1967).

Burkitt (1969) added 2% bentonite in pellets fed cattle and obtained

168 grams of greater daily gain. As such studies with bentonite are

limited and have yielded inconsistent results, it is evident that there

are factors that are not well understood about its use in feeds for ruminants.






10

Soft Phosphate

Soft phosphate is a colloidal clay that is produced during the

mining of rock phosphate. In the livestock industry research has been

conducted to determine the biological availability of phosphorus from

soft phosphate for ruminants. Anderson, Cheng and Burroughs (1956) and

Long et al. (1956) reported that the availability of phosphorus from

soft phosphate was lower than that from dicalcium phosphate or steamed

bone meal. Using the isotope dilution method Lofgreen (1960) determined

the true digestibility of phosphorus from soft phosphate to be 14%

compared to 40, 46 and 33% in dicalclumphosphate, bone meal, and calcium

phytate, respectively. Wise, Wentworth and Smith (1961), working with

growing calves and measuring feed intake, weight gain and bone concen-

tration of phosphorus as criteria, rated the availability of phosphorus

from soft phosphate to be below that of defluorinated rock phosphate,

Curacao Island phosphate and dicalclum phosphate. Ammerman et al.

(1957) compared soft phosphate, bone meal, Curacao Island phosphate,

two calcined defluorinated phosphates and two dicalcium phosphates in

rations fed steers and observed that phosphorus retention and blood

phosphorus levels were equivalent in the treatment groups. When lambs

were fed phosphorus from some of these sources by the Investigators,

calcium phosphate and Curacao Island phosphate were well utilized, but

soft phosphate and a calcined defluorinated phosphate were poorly

utilized.

The high fluorine content of soft phosphate is another factor

that limits its utilization In livestock feeds. Hobbs et al. (1954)

reported that when the diet of growing steers exceeds 200 ppm of

fluorine the animals have decreased feed consumption, weight gains,






11

stiffness and impaired vision. Ammerman et al. (1957) and Ammerman et

al. (1964) observed soft phosphate to contain 1.44% fluorine. Soft

phosphate containing this level of fluorine added at 1% concentration

to a diet would provide 134 ppm of fluorine ir the feed. In view of

data reported by Hobbs et al. (1954), Ammerman et al. (1957), and

Ammerman et al. (1964) soft phosphate should not be incorporated in

the diet of growing-fattening animals at a level greater than 1%.


California Net Energy System

The California net energy system was developed by G. F. Lofgreen,

W. N. Garrett, and others. It is the culmination of the ideas and

work of many Investigators.

Disagreement existed among researchers interested in the efficiency

of energy utilization at and above maintenance. Klieber (1961) postulated

that the energy utilization for maintenance is greater than it is for

production. Blaxter (1956) contended that energy utilization is best

from maintenance to an intermediate level of gain. Differences such as

these were difficult to resolve due to the cost of classical calorimetric

balance trials. Lofgreen and co-workers attempted to develop a new

system to evaluate energy utilization.

Lofgreen and Otagaki (1960) introduced the concept of comparative

slaughter technique for determination of energy retention. This method

required the determination of specific gravity of the carcass of

representative animals at the beginning of the feeding trial and those

in the feedlot at the termination of the trial. From specific gravity

values fat and protein percentages in the carcass can be calculated by

formulas developed by Reid, Wellington and Dunn (1955), and percent body

water as recommended by Kraybill, Bitter and Hankins (1952). Energy





12

contained in the body fat and protein was calculated by multiplying

9367 kcal times kg of fat (Blaxter and Rook, 1953) and 5686 kcal times

kg of protein (Garrett, 1958). Using this method an investigator can

calculate the total energy contained in a carcass. Lofgreen, Hull and

Otagaki (1962) derived a formula to calculate empty body weight from

warm carcass weight, so that energy retention could be related to empty

body weight gain.

Now that the energy retained by the animal could be calculated,

Lofgreen, Bath and Strong (1963) introduced a method to identify net

energy in the feed into net energy for maintenance and net energy for

production.

To determine net energy for maintenance and production, metabolizable

energy must first be determined. In the California net energy system

metabolizable energy needs to be determined as usual by subtracting energy

contained in the feces, urine and methane from the gross energy intake.

The amount of methane produced by an animal fed any diet can be calculated

from the digestible nitrogen-free-extract portion (Bratzler and Forbes,

1940). Energy in the methane is determined by multiplying 213 kcal times

the moles of methane produced (Morrison and Boyd, 1970).

Net energy for maintenance Is determined from metabolizable energy

in the feed. Garrett, Lofgreen and Myer (1964) demonstrated that the

total heat production for steers could be calculated by the following

formula:

Log HP = 1.9073 + 0.00148 ME kcal/W-75kg

HP is the heat produced and ME is the metabolizable energy. Lofgreen and

Garrett (1968) stated that net energy for maintenance is equal to heat

produced by the animal at zero energy intake. The heat produced at zero

energy intake is 77 kcal times the metabolic body weight of the animal.





13

This value can be used as one point on a graph. A second point for

heat production on the graph can be calculated by inserting the

metabolizable energy value determined directly on the feed, in the

above formula. Next the metabolizable energy equal to the heat produc-

tion can be read directly from the graph. Then the grams of feed

required to equal heat produced can be calculated by dividing the heat

produced expressed as kcal by the metabolizable energy expressed as

kcal per gram of feed. Net energy for maintenance in the feed is then

calculated by dividing the grams of feed that are needed to provide

the kcal In the previously defined heat production into 77 kcal. An

example of this procedure as determined by Lofgreen and Garrett (1968)

follows.

Energy Intake and heat production were found to be equal at 131

kcal of metabolizable energy intake. This value was determined from

plotting heat produced per kg of metabolic body weight versus metabo-

lizable energy intake in kcal per kg of metabolic body weight. The

metabolizable energy value of this diet was 2.04 kcal per gram. By

dividing the 131 kcal of metabolizable energy by 2.40 kcal per gram of

feed, It is found that it requires an Intake of 64.2 g of this feed per

kg of metabolic body weight to produce the energy required for maintenance.

The energy required for maintenance was established as 77 kcal per kg

of metabolic body weight. The net energy for maintenance for this

ration Is equal to 77 kcal divided by 64.2 or 1.20 kcal per gram

(1.20 Mcal per kg).

Net energy for production is determined by the difference in energy

retention divided by the difference in feed intake at two levels of

feeding. The difference in energy retention is determined by the

comparative slaughter technique previously described. The retention























values are expressed as kcal retained per kg of metabolic weight. The

feed intake values are expressed as grams of feed intake per kg of

metabolic weight. The net energy for production in the feed is then

expressed as kcal per gram. An illustration of such a determination

(Lofgreen and Garrett, 1968) is listed below:


Level of feeding


Ad libitum

Equilibrium

Difference

NEg = 41/82 or 0.5 kcal/g


Feed intake
g per W.75kg

146

64

82


Energy gain
kcal per W-75kg

41

0

41








EXPERIMENTAL PROCEDURE

The present study involved two experiments that were designed

to determine the digestibility and energy efficiency of feedlot diets

containing high levels of sorghum grain.


Experiment I

This experiment was designed to determine the digestibility of

dietary components of bird-resistant sorghum grain rations with and

without added bentonite or soft phosphate.

Six crossbred Hereford X Angus steers that averaged 379 kg body

weight were randomly assigned to dietary treatments using a 3 X 3

crossover Latin square design, as shown in Table 1. The treatments

were diets that contained bird-resistant sorghum grain (BR), BR plus

2S bentonite, and BR plus 1% soft phosphate. A detailed tabulation

of the composition of the diets Is presented In Table 2. The steers

were adjusted to the diets during a 14-day period. During the first

eight days of adjustment the steers were fed in stalls ad libitum to

determine voluntary feed intake. The amount of feed offered to the

steers was then decreased to 85% of each steer's voluntary feed intake

and they were kept in the stalls two more days. At the end of the

above ten-day period the steers were moved to metabolism racks where

they were allowed to adjust to the racks and the diets for four

additional days. Feces and urine were then collected for five days,

which completed a 19-day cycle.

Representative samples of diets were obtained daily and composite




















TABLE 1. EXPERIMENTAL DESIGN OF METABOLISM TRIAL WITH STEERS
FED SORGHUM GRAIN DIETS CONTAINING ADDED BENTONITE
OR SOFT PHOSPHATEa


Animal 1 2 3 4 5 6


Period I C A B C B A

II A C C B A B

III B B A A C C


aA is control diet.

B is 2% bentonite diet.

C is 1% soft phosphate diet.













TABLE 2. INGREDIENTS OF SORGHUM GRAIN DIETS WITH ADDED BENTONITE
OR SOFT PHOSPHATE FED TO.STEERS DURING METABOLISM TRIAL,
AS FED BASIS


Control 2% Bentonite 1% Soft
Phosphate

Ingredients g g g

Bird-resistant sorghum grain 78.30 76.30 77.85

Soybean meal, 49% protein 8.00 8.00 8.00

Hay, Coastal Bermuda 10.00 10.00 10.00

Molasses, Cane 2.00 2.00 2.00

Defluorinated phosphate 1.10 1.10 0.55

Iodized salt 0.50 0.50 0.50

Trace mineral 0.10 0.10 0.10

Vitaminsb -

Bentonite 0.00 2.00 0.00

Soft phosphate 0.00 0.00 1.00


aTrace mineralized salt contained 250 mg manganese, 100 mg Iron,
50 mg sulfate sulfur, 33 mg copper, 15 mg cobalt, 8 mg zinc and
7 mg iodine per gram.
bvitamin concentrate added at 4.5g/453.51 kg which provides 2,200
IU/kg of feed of vitamin A and 500 IU/kg of feed of vitamin D.





18

at the end of the feces and urine collection period. Feces were

collected twice daily and stored in metal cans with plastic liners

and lids. After mixing each day's excreta, 10% of the material was

frozen in plaxtic bags for later analysis. Urine was collected in

plastic pails containing 150 ml dilute hydrochlorid acid (1:4) and 10

ml of toluene as preservatives. Ten percent of each day's urine was

saved and composite during the five-day collection period.

The frozen fecal samples were thawed overnight, composite,

thoroughly mixed, dried at 600 C in a forced air oven for 72 hours,

and then equilibrated with atmospheric moisture for 48 hours. Following

this all samples were ground through a 30 mesh screen in a Wiley mill.

The diets and feces were analyzed for proximate analysis consti-

tuents, energy, and tannin content. Urine was analyzed for nitrogen,

energy, and tannins. The proximate composition and adiabatic calorimeter

energy were determined by the A.O.A.C. (1970) procedures, and the tannins

were determined by the method outlined by Burns (1963). The statistical

method used was least squares analysis (Harvey, 1960).

Composition of the diets on:a dry matter basis is shown in Table 3.

All diets were quite similar in proximate analysis, energy, and tannin

values.


Experiment II

This experiment was designed to determine net energy for maintenance

and net energy for gain values for sorghum grain diets using the

California net energy procedure which includes a metabolism and feedlot study.

In a 3 X 3 Latin square design study, three Angus steers that

averaged 285 kg of body weight were randomly assigned to dietary

treatments as presented in Table 4. The three treatments were diets













TABLE 3. COMPOSITION OF SORGHUM GRAIN DIETS CONTAINING ADDED
BENTONITE OR SOFT PHOSPHATE FED TO STEERS DURING
METABOLISM TRIAL, DRY MATTER BASISa


Control 2% Bentonite 1% Soft
Phosphate


Ash, % 4.53 6.16 4.99

Ether extract, % 1.20 1.56 1.12

Protein, % 12.84 12.75 12.61

Fiber, % 5.54 5.59 5.57

NFE, %b 75.89 73.94 75.71

Energy, kcal/gc 4.26 4.17 4.23

Tannins, % 1.66 1.45 1.45

aMoisture, % as fed basis 15.12 14.18 14.89


bNitrogen-free-extract.

CDetermined with adiabatic


calorimeter.




















TABLE 4. EXPERIMENTAL DESIGN OF METABOLISM PHASE OF NET ENERGY
STUDY WITH STEERS FED CORN, NON-BIRD-RESISTANT, OR
BIRD-RESISTANT SORGHUM GRAIN DIETSa


Animal 03 28 35


Period I BR Corn NBR

II Corn NBR BR

III NBR BR Corn


aCorn is corn diet.

NBR is non-bird-resistant sorghum grain diet.

BR is bird-resistant sorghum grain diet.





21

that contained either high quantities of corn, non-bird-resistant

sorghum grain (NBR) or bird-resistant sorghum grain (BR). A detailed

description of the diets is presented in Table 5. Handling of the

cattle, feed, feces and urine was exactly the same as that described

in experimental procedure I above.

In the feedlot part of the study, 54 crossbred, Hereford and

Angus steers that averaged 326 kg of body weight were randomly assigned

to six dietary treatments, as shown in Table 6. All steers received

feed ad libitum for ten days at which time one steer was randomly

selected from each treatment group to be slaughtered and provide energy

data for the steers at the start of the feeding period.

The remaining steers were shrunk for a period of 12 hours prior

to the start of the feeding trial, individually weighed, implanted with

36 mg of diethylstilbestrol and started on their feeding program.

Steers in the three dietary groups allowed only the restricted intake

of feeds were fed to gain an average of 0.68 kg per head daily. This

rate of gain figure was calculated and regulated according to their

body weight and the expected gain data published by NRC bulletin (1970).

The other three corresponding groups of steers were fed their diets ad

IIbitum. Steers were weighed by groups every 28 days In order that

feeding levels for restricted fed groups could be determined and

readjusted if necessary. At the end of the feeding period, all animals

were again shrunk 12 hours, individually weighed and transported to

Gainesville, Florida, for slaughter. All animals were slaughtered and

the carcasses chilled according to accepted research procedures.

Specific gravity was determined on each carcass by hydrostatic

weighing of each chilled right quarter (Kraybill, Bitter and Hanklns,

1952) and using the formula:













TABLE 5. INGREDIENTS OF CORN, NON-BIRD-RESISTANT AND BIRD-
RESISTANT SORGHUM GRAIN DIETS FED TO STEERS IN
METABOLISM AND FEEDLOT PHASES OF NET ENERGY
DETERMINATION, AS FED BASISa


Corn NBR BR


Ingredients g g g

Corn 61.00 0.00 0.00

Non-bird-resistant sorghum
grain 0.00 61.00 0.00

Bird-resistant sorghum grain 0.00 0.00 61.00

Forage sorghum silage 35.00 35.00 35.00

Soybean oil meal, 44% protein 3.04 3.04 3.04

Urea (45% N) .2872 .2872 .2872

Defluorinated phosphate .4416 .4416 .4416

Trace mineralized saltb .2208 .2208 .2208

Perma Dual 30Ac .0048 .0048 .0048

Baciferm 40d .0056 .0056 .0056


aCorn is corn diet.
NBR is non-bird-resistant sorghum grain diet.
BR is bird-resistant sorghum grain diet.

bTrace mineralized salt contained 97.5% NaCI, 250 mg manganese, 100 mg
iron, 50 mg sulfate sulfur, 33 mg copper, 15 mg cobalt, 8 mg zinc, and
7 mg iodine per gram.

CPerma Dual 30A contained 30,000 IU of vitamin A per gram.

dBaciferm 40 contained 90 mg of zinc bacitracin per gram.




















TABLE 6. EXPERIMENTAL DESIGN OF CORN, NON-BIRD-RESISTANT AND
BIRD-RESISTANT SORGHUM GRAIN DIETARY TREATMENTS FOR
STEERS DURING FEEDLOT PHASE OF NET ENERGY STUDYa


Diet Corn NBR BR


Ad libitum intake

No. of animals 9 9 9


Restricted

No. of animals 9 9 9


aCorn is corn diet.

NBR is non-bird-resistant sorghum grain diet.

BR Is bird-resistant sorghum grain diet.





24

Carcass specific gravity = Right side weight in air
Right side weight in air right side weight
in water

Weights in water were taken in a tank of 48 inches diameter X 8 feet

high located in a cooler maintained at a temperature of 34 to 360 F.

Care was taken to minimize weighing error by carefully placing carcasses

in water to reduce trapped air and by taking scale readings immediately

after the carcass was submerged. Weights in water were recorded to the

nearest ounce and weights in air recorded to the nearest 0.5 pounds.

The diets and feces were analyzed for proximate analysis consti-

tuents and energy content. Urine was analyzed for nitrogen and energy

by A. 0. A. C. (1970) procedures. Tannins in the diets were determined

by the method outlined by Burns (1963).

Composition of the diets on a dry matter basis is shown in Table 7.

All diets contained similar amounts of ash and energy. The NBR diet

was slightly higher in percent protein and was slightly lower in

nitrogen-free-extract. The corn diet contained the highest percentage

ofether extract. The BR diet had the most crude fiber and tannins. The

higher crude fiber value may be related to the increased percentage of

tannins which form a complex with the fiber portion (VanSoest, 1969).













TABLE 7. COMPOSITION OF CORN, NON-BIRD-RESISTANT AND BIRD-RESISTANT
SORGHUM GRAIN DIETS FED TO STEERS IN METABOLISM AND FEEDLOT
PHASES OF NET ENERGY DETERMINATION, DRY MATTER BASISa,b


Corn NBR BR


Ash, % 3.07 3.46 3.33

Ether extract, % 4.14 2.55 2.51

Protein, % 12.71 13.67 12.34

Fiber, % 5.57 6.66 7.28

NFE, %c 74.51 73.66 74.55

Energy, kcal/gd 4.40 4.46 4.46

Tannins, % 0.51 0.94 2.15

aMoisture as fed basis, % 37.17 37.40 36.91


bCorn is corn diet.
NBR is non-bird-resistant sorghum grain diet.
BR is bird-resistant sorghum grain diet.

cNitrogen-free-extract.
dDetermined with adiabatic calorimeter.













RESULTS AND DISCUSSION

Experiment I

The addition of 2% bentonite or 1% soft phosphate to the sorghum

grain diet had no significant effect on the digestion of dry matter,

organic matter, fiber, nitrogen-free-extract and total digestible

nutrients (Table 8). The slight decrease in dry matter and organic

matter digestion when 2% bentonite was added to the diet agrees with

results reported by Martin, Clifford and Tillman (1969). When 2%

bentonite was added to the control diet, it decreased (P < .01) apparent

ash absorption. Since the bentonite diet contained more ash than the

other diets it appears that the ash portion contributed by the bentonite

is not digestible thus lowering the overall apparent ash absorption of

the diet. Soft phosphate had no significant effect on apparent ash

absorption. Nitrogen digestion was reduced (P < .01) when bentonite was

added to the sorghum grain diet while the addition of soft phosphate had

no effect. However, Martin, Clifford and Tillman (1969) observed no

difference in nitrogen digestion when 2% bentonite was added to sorghum

grain diets. These authors fed a non-bird-resistant sorghum grain diet

while cattle in this experiment were fed a bird-resistant sorghum grain

diet. Soft phosphate added at 1% of the diet decreased fat digestion

(P < .05) in comparison to the diets with and without added bentonite.

The decreased fat digestion may have been due to the higher calcium content

of the soft phosphate diet.

There were no significant differences in the percentage of tannins in













TABLE 8. PERCENT DIGESTION OF DRY MATTER, ORGANIC MATTER, ETHER
EXTRACT, FIBER, NITROGEN, NITROGEN-FREE-EXTRACT, APPARENT
ASH ABSORPTION AND TOTAL DIGESTIBLE NUTRIENTS IN METABOLISM
TRIAL WITH SORGHUM GRAIN DIETS CONTAINING ADDED BENTONITE
OR SOFT PHOSPHATEa,b,c,d


Control 2% Bentonite 1% Soft
Phosphate


Dry matter, % 62.13 57.12 62.98

Organic matter, % 63.36 60.05 64.53

Ash, % 35.77a 10.77b 29;10a

Ether extract, % 10.97c 38.15c -6.32d

Fiber, % 60.29 54.04 55.42

Nitrogen, % 40.83a 30.37b 42.15a

NFE, %e 68.84 65.85 70.10

TDN, f 62.75 57.59 62.97

a,bValues within rows differing with superscripts a and b are
significant at P < .01.

c,dValues within rows differing with superscripts c and d are
significant at P < .05.

eNitrogen-free-extract.

fTotal digestible nutrients.





28

the feces or urine, nitrogen retention, energy digested, or metabolizable

energy when 2% bentonite or 1% soft phosphate was added to the control

diet (Table 9). Steers fed the diet with 2% added bentonite excreted

76.76% of the dietary tannins, in comparison to cattle fed the control

diet and soft phosphate diet which excreted 75.49 and 64.83% of the

dietary tannins, respectively.

Addition of bentonite decreased slightly the amount of nitrogen

retained while Martin, Clifford and Tillman (1969) observed that the

addition of 2% bentonite slightly increased nitrogen retention. Neither

experiment demonstrated a statistically significant effect.

Additions of 2% bentonite or 1% soft phosphate had no significant

effect on energy digestion or determined metabolizable energy. When

metabolizable energy was calculated from total digestible nutrients as

outlined by the NRC (1970), the average difference in the calculated

values and the determined values was only 5.45%. This comparison

supports the calculation of metabolizable energy from total digestible

nutrients by the NRC method if a determined metabolizable energy cannot

be obtained.

In conclusion, the addition of 2% bentonite or 1% soft phosphate

did not enhance the digestion of dry matter, total digestible nutrients,

energy, or the metabolizable energy and nitrogen retention of the bird-

resistant sorghum grain diet.


Experiment II

Steers fed the corn diet digested more (P < .05) dry matter,

organic matter, nitrogen and nitrogen-free-extract than cattle fed

either the non-bird-resistant or the bird-resistant sorghum grain

diet (Table 10). Digestibility of ether extract, fiber, nitrogen













TABLE 9. PERCENT TANNINS IN FECES AND URINE,
PERCENT ENERGY DIGESTED, DETERMINED
AND CALCULATED METABOLIZABLE ENERGY
WITH SORGHUM GRAIN DIETS CONTAINING
SOFT PHOSPHATE FED STEERSa


NITROGEN RETENTION,
METABOLIZABLE ENERGY
FROM METABOLISM TRIAL
ADDED BENTONITE AND


Control 2% Bentonite 1% Soft
Phosphate


Tannins in feces/intake, % 62.41 61.43 53.81

Tannins in urine/intake, % 13.08 15.31 11.01

Nitrogen retention, g/day 8.22 -4.65 3.59

Energy digested, % 58.63 54.48 59.90

Metabolizable energy, Mcal/kg 2.14 1.95 2.20

Metabolizable energy, Mcal/kgb 2.27 2.08 2.28


aValues within rows that differ in superscript a and b are significantly
different at P < .05; none of the Items tested were significantly
different.

bCalculated metabolizable energy was derived by multiplying total
digestible nutrients times 3.6155 Mcal/kg (NRC, 1970).













TABLE 10. PERCENT DIGESTION OF DRY MATTER, ORGANIC MATTER, ETHER
EXTRACT, FIBER, NITROGEN, NITROGEN-FREE-EXTRACT, NITROGEN
RETENTION OR APPARENT ASH ABSORPTION IN CORN, NON-BIRD-
RESISTANT AND BIRD-RESISTANT SORGHUM GRAIN DIETS FED
STEERS DURING METABOLISM PHASE OF NET ENERGY DETERMINATIONa,b,c


Corn NBR BR


Dry matter, % 75.37b 63.63c 62.61c

Organic matter, % 76.29b 64.99c 63.46c

Ash, % 46.75 18.94 37.93

Ether extract, % 79.80 53.64 55.75

Fiber, % 44.45 25.43 31.47

Nitrogen, % 61.52b 46.93c 37.64c

NFE, %d 80.93b 72.53c 70.94c

Nitrogen retention, g/day 12.30 -1.86 2.01


aCorn is corn diet.
NBR is non-bird-resistant sorghum grain diet.
BR is bird-resistant sorghum grain diet.

b,cValues on the same line bearing different superscripts differ
significantly (P < .05).
dNFE is nitrogen-free-extract.






31

retention, and apparent absorption of ash were not significantly different

in the three diets. A trend of lower digestibility of the bird-resistant

sorghum grain follows the trends of reported values in the literature

(Fox et al., 1970; Newland, Klosterman and Fox, 1970; and Hinders and Eng,

1971).

The corn diet contained more (P < .05) digestible energy and total

digestible nutrients than either the non-bird-resistant or bird-resistant

sorghum grain diet (Table 11). There were no significant differences

between the two types of sorghum grain diets. Metabolizable energy in

the corn diet was higher (P < .01) than either grain sorghum diet. From

these data it can be concluded that the digestibility of non-bird-

resistant and bird-resistant sorghum grain diets is lower for feedlot

cattle than the digestibility of the corn diet.

Since metabolizable energy values for diets are not always reported,

they are calculated by multiplying the percentage of total digestible

nutrients times 3.6155 which gives the metabolizable energy in terms of

Meal per kg (NRC, 1970). The metabolizable energy values calculated by

this method in the present study average within 1.48% of the actual

determined values (Table 11). As in experiment I this supports the use

of NRC formula for calculating metabolizable energy if an actual value

cannot be obtained.

Performance data for the steers during the feedlot phase of the net

energy determination are presented in Table 12. Steers fed the corn diet

ad libitum gained more (P < .01) than steers similarly fed the bird-

resistant sorghum grain diet or any of the three dietary groups restricted

In feed intake. The corn diet fed ad libitum did not produce gains

significantly greater than the full fed non-bird-resistant sorghum grain





















TABLE 11. DIGESTIBLE ENERGY, TOTAL DIGESTIBLE NUTRIENTS, DETERMINED
METABOLIZABLE ENERGY AND CALCULATED METABOLIZABLE ENERGY
IN CORN, NON-BIRD-RESISTANT AND BIRD-RESISTANT SORGHUM
GRAIN DIETS FED STEERS DURING METABOLISM ENERGY TRIAL
PHASE OF NET ENERGY DETERMINATIONa


Corn NBR BR


Digestible energy, % 74.55b 63.09c 59.46c

TDN, %d 79.47b 65.34C 64.37c

Metabolizable energy, Mcal/kg 2.84e 2.40f 2.29f

Metabolizable energy, Mcal/kgg 2.87 2.36 2.33

aCorn is corn diet.
NBR is non-bird-resistant sorghum grain diet.
BR Is bird-resistant sorghum grain diet.

b,cValues on the same line with different superscripts differ
significantly (P < .05).

dTDN is total digestible nutrients.

e,fValues on the same line with different superscripts differ
significantly (P < .01).

gCalculated metabolizable energy was derived by multiplying total
digestible nutrients times 3.6155 Mcal/kg (NRC, 1970).




















TABLE 12. PERFORMANCE OF STEERS FED CORN, NON-BIRD-RESISTANT OR
BIRD-RESISTANT SORGHUM GRAIN DIETS DURING FEEDLOT
PHASE OF NET ENERGY DETERMINATIONa


Corn NBR BR

re- ad re- ad re- ad
stricted liFTtum stricted libiTum stricted libitum


Number of steers 8 8 8 8 8 8

Avg initial wt, kg 317 315 326 325 319 317

Avg final wt, kg 420 479 428 469 396 444

Avg daily gain, kg 0.83cd 1.33b 0.76cd 1.16bc 0.68d 1.01c

Days fed 128 128 128 128 128 128

Avg dry matter intake,
kg/day 5.11 8.40 i5.98 8.95 6.43 10.16

Feed per kg gain 6.16 6.31 7.98 7.62 9.41 10.03


Corn is corn diet.
NBR is non-bird-resistant sorghum grain diet.
BR Is bird-resistant sorghum grain diet.
b,c,dyalues on the same line with different superscripts differ
significantly (P < .01).






34

diet. There were no significant differences in gains of steers fed

the two types of sorghum grain diets. Steers restricted In their feed

intake had relatively the same responses to the three diets as those

full fed. That is, those fed the limited corn diet produced slightly

greater gains than those fed the non-bird-resistant sorghum grain diet

and those fed the bird-resistant sorghum grain diet gained at a slightly

slower rate than the other two groups.

Average dry matter intake was quite similar with the steers fed

the non-bird-resistant sorghum and corn diets but slightly greater

for those fed the bird-resistant sorghum grain diet. Feed efficiency

was best for the limited and ad libitum fed corn dietary groups, poorest

for those fed the non-bird-resistant sorghum grain diet and Intermediate

for those fed the bird-resistant sorghum grain diet. The generally lower

feed efficiency of the two types of sorghum grain diets Is apparently

due to the overall lower availability of the nutrient components of the

diets as shown in Tables 10 and 11.

Daily heat production as related to metabolizable energy intake is

shown in figure 1. These data were derived from 236 cattle (Lofgreen and

Garrett, 1968). Lofgreen and Garrett (1968) stated that at zero energy

intake the heat produced by cattle is within the range of 72 to 83

kcal per kg of metabolic body weight, with an average of 77 kcal. The

graph line of figure 1 has its origin at 77 kcal per kg of metabolic body

weight. The values for heat produced in the present study by the three

experimental diets when plotted in figure 1 were in close proximity to

the line obtained by Lofgreen and Garrett. Therefore, In determining

the energy balance between intake and heat production, Lofgreen and

Garrett's line was used.' The energy balance of this line occurs at an



























* Corn diet

D Non-bird-resistant sorghum grain diet

0 Bird-resistant sorghum grain diet


50 100 150 200 250 300 350

Daily metabolizable energy intake, kcal/W'75kg

FIGURE 1. VALUES OBTAINED IN THE PRESENT STUDY
PLOTTED ALONGSIDE THE GRAPHIC LINE PUBLISHED BY
LOFGREEN AND GARRETT (1968)







36

intake of 131 kcal of metabolizable energy per kg of metabolic body

weight (Lofgreen and Garrett, 1968).

Empty body weight gains and composition of empty body weight gain

values used to calculate the net energy for gain values are presented

in Table 13. The corn diet produced more empty body weight gain than

the sorghum diets when full fed cattle are compared. The same relative

gains were made with the three diets when they were restricted. The

corn and non-bird-resistant sorghum grain diets produced somewhat higher

percentages of fat than the bird-resistant sorghum grain diets both

with the full fed and restricted cattle. Since these values are

based on the mean of six animals for initial body composition, there

is no statistical evaluation of the variations in treatment groups.

The percentage of protein was approximately 3-4% higher in the limited

fed dietary groups than in those full fed the diets. Only moderate

differences In percentage of protein occurred due to the dietary

treatments.

Energy required for maintenance was calculated by multiplying

metabolic body weight in kg times .077. This gave a net energy for

maintenance value in Mcal. Energy retained per day was determined by

formulas from Lofgreen and Garrett (1968) and show cattle receiving the

corn diet ad libitum retained the most energy. This also occurred when

the corn diet was restricted. Total net energy is the sum of the energy

required for maintenance per day plus the daily energy gain. The net

energy values were determined according to the procedure of Fox et al.

(1970) in which one divides the total net energy by the daily dry matter

intake. These authors reported values of 1.29 for a corn griin and mixed

hay diet and .94 for a bird-resistant sorghum grain and mixed hay diet.







TABLE 13. NET ENERGY FOR MAINTENANCE AND NET ENERGY FOR GAIN, VALUES FOR CORN, NON-BIRD-RESISTANT
AND BIRD-RESISTANT SORGHUM GRAIN DIETSa


Corn NBR BR

restricted ad libitum restricted ad libitum restricted ad libitum

Avg empty body weight gain, kg 104 149 89 128 80 109

Composition of gain
Fat, % 19.12 35.61 15.40 37.66 8.19 30.07

Protein, % 18.62 15.30 19.03 14.65 20.59 16.58

Avg metabolic weight, W.75kg 84.1 88.9 85.5 88.9 82.2 86.8

Energy required for maintenance,
Mcal/dayb 6.476 6.845 6.584 6.845 6.329 6.684

Energy gain, Mcal/day 2.315 4.895 1.749 4.365 1.214 3.212

Total net energy, Mcal/day 8.791 11.740 8.333 11.210 7.543 9.896

Net energy, Mcal/kg DMc 1.72 1.40 1.39 1.25 1.17 0.97

NEm, Mcal/kg ration DM 1.67 1.67 1.41 1.41 1.35 1.35

NEg, Mcal/kg ration DM .82 .82 .93 .93 .57 .57


aCorn Is corn diet. NBR is non-bird-resistant
grain diet.


sorghum grain diet. BR Is bird-resistant sorghum


bEnergy required for maintenance Is determined by multiplying .077 times kg of metabolic body weight.

cNet energy Is determined as outlined by Fox et al. (1970) which is the sum of energy for maintenance
plus energy gain divided by dry matter intake.





38

These values are similar to the values determined for the.corn and

bird-resistant sorghum grain diet fed in the present study.

In the application of net energy in the present study by the

manner used by Fox et al. (1970) it was apparent that It is not

constant for level of intake. The restricted level of intake In all

three diets produced higher net energy values than did the ad libitum

level of intake. Another limitation of the net energy values as

calculated by Fox et al. (1970) is that there is no procedure for

predicting gains.

Following Lofgreen and Garrett'l(1968) procedure for determining

net energy for maintenance (NEm), the corn diet produced the highest

value. The non-bird-resistant diet was slightly greater in net energy

for maintenance than the bird-resistant sorghum grain diet. The

maintenance values determined for these diets are somewhat lower than

those reported in the NRC bulletin (1970) for the combination of

dietary ingredients. The non-bird-resistant sorghum grain diet had

a net energy for gain (NEg) value of .93 compared to .82 Mcal per kg

of ration dry matter in the corn diet. The corresponding bird-resistant

diet had a net energy for gain value of .57 Mcal per kg of ration. Net

energy for gain values for the corn and bird-resistant sorghum grain

diets are lower than reported in the NRC bulletin (1970) as calculated

on an individual ingredient basis. The value for the non-bird-resistant

sorghum grain diet is slightly higher than reported values.. Due to the

large.difference In the two types of sorghum grain diets it is apparent

that additional studies such as the present one should be made on the

new varieties and types of sorghum grains.

In addition to the net energy system (NRC, 1970) used above for

evaluating gains in cattle, there is the one proposed by Blaxter (1962)















39

based on the metabolizable energy values determined for the rations.

Table 14 presents values for actual gains of steers in the present

study compared to values that would be predicted by the metabolism

and feedlot data using both systems for predicting gain. The two

systems are quite close in predicting gains on the corn diet fed ad

libitum; however, the Blaxter system is closer to the actual values

with the bird-resistant sorghum grain diets, and the NRC system is

closer with the non-bird-resistant diets. The NRC system was

consistently closer t the actual values with all limited fed dietary

groups. From the overall data the NRC system probably should be

considered to be the better of the two systems. Obviously more

investigation is needed to evaluate the two systems with limited

steers.

In conclusion, the corn diet contains more digestible nutrients

and produces faster gains with less feed intake than either sorghum

grain diet. The non-bird-resistant sorghum grain diet was slightly

superior.for feedlot cattle in producing rate of gain than the bird-

resistant sorghum grain diet.






















TABLE 14. ACTUAL COMPARED TO PREDICTED BODY WEIGHT GAINS
CALCULATED WITH BLAXTER'S METABOLIZABLE ENERGY
EQUATIONS AND THE NRC ENERGY FOR MAINTENANCE
AND GAIN VALUES OF STEERS FED CORN, NON-BIRD-
RESISTANT AND BIRD-RESISTANT SORGHUM GRAIN DIETSa,bc


Corn NBR BR

re- ad re- ad re- ad
stricted libitum stricted libitum stricted libitum


Actual gain,
kg/day 0.83 1.33 0.76 1.16 0.68 1.01

Predicted gains

Blaxter's
system, kg/day 0.51 1.26 0.37 0.84 0.45 0.92

NRC values,
kg/day 0.67 1.43 0.60 1.20 0.77 1.46


acorn is corn diet.
NBR is non-bird-resistant sorghum grain diet.
BR is bird-resistant sorghum grain diet.

bBlaxter's metabolizable energy equations were published by Blaxter (1962).


CNRC gain values were derived from information
bulletin (1970).


given In:the NRC








SUMMARY

Six crossbred Hereford X Angus steers were randomly assigned to a

3 X 3 crossover Latin square designed metabolism trial to determine the

digestibility of bird-resistant sorghum grain diets with and without

added bentonite or soft phosphate. The addition of 2% bentonite or 1%

soft phosphate to the control diet had no significant effect on the

digestion of dry matter, organic matter, fiber, nitrogen-free-extract

or total digestible nutrients. Bentonite added in at 2% of the diet

decreased nitrogen digestion (P < .01) and the addition of 1% soft

phosphate decreased ether extract digestion (P < .05). Neither

additive affected the digestion or urinary excretion of dietary tannins.

Energy digestion, nitrogen retention and metabolizable energy were not

affected by dietary treatments.

Fifty-seven crossbred, Hereford and Angus feedlot type steers were

used.to determine the net energy values of corn, non-bird-resistant

and bird-resistant sorghum grain diets. Prior to the feedlot phase a

metabolism trial phase with three steers in a 3 X 3 Latin square was

carried out to establish metabolizable energy value for the various

diets. Digestibility of other nutrients was also determined in this

metabolism trial. The corn diet contained more digestible dry matter,

organic matter, nitrogen, nitrogen-free-extract, energy, metabolizable

energy and total digestible nutrients than either of the two types of

sorghum grain diets. The non-bird-resistant sorghum grain diet contained

slightly more digestible dietary components than the bird-resistant

sorghum grain diet.









42

During the feedlot phase of the study, the corn diet produced

more live weight gains on less feed than the bird-resistant sorghum

grain diet. Steers fed the non-bird-resistant sorghum grain diet

gained slightly faster and consumed less dry matter than steers fed

the bird-resistant sorghum grain diets.

The net energy for maintenance values of the corn, non-bird-

resistant and bird-resistant sorghum grain were 1.67, 1.41 and 1.35

Meal per kg of diet, respectively. The corresponding values for net

energy for gain were .82, .93 and .57 Mcal per kg of diet, respectively.

Taking all data into account the best diet for feedlot cattle was

the corn diet, followed by the non-bird-resistant and finally the bird-

resistant sorghum grain diet.

Metabolizable energy calculated by multiplying the NRC factor times

the total digestible nutrients gave values within 5% of those actually

determined. Blaxter's metabolizable energy system and the net energy

for maintenance and gain values in tables from the NRC bulletin on

Nutrient Requirements of Beef Cattle were compared in regard for

predicting gains. Both procedures for predicting gains come within

.1 kg per day of those actually observed when steers were fed the corn

diet ad libitum in the present study. The NRC system Is closer to

actual gain values for the non-bird-resistant sorghum grain diets while

Blaxter's system is closer with the bird-resistant sorghum grain diet.

Predicted gains for steers in the limited dietary Intake treatments were

much closer using the NRC tables than Blaxter's system.



































APPENDIX









TABLE 15. RATE OF GAIN, DRY MATTER CONSUMPTION AND FEED EFFICIENCY DETERMINED FROM CATTLE FED CORN,
NON-BIRD-RESISTANT OR BIRD-RESISTANT SORGHUM GRAIN DIETS DURING FEEDLOT PHASE OF NET ENERGY
DETERMINATIONa


Item Time Corn NBR BR Corn NBR BR
In days restricted restricted restricted ad libltum ad libitum ad llbitum

0- 28 0.49 0.61 0.48 1.57 1.22 1.21

28- 56 1.34 0.97 0.83 1.69 1.47 1.51

Average daily 56- 84 0.79 1.04 0.91 1.26 1.21 0.84
gain, kg
84-112 0.47 0.61 0.35 1.01 0.76 0.77

112-128 1.26 0.46 0.96 0.96 1.15 0.53

0-128 0.83 0.76 0.68 1.33 1.16 1.01

0- 28 1137 1307 1318 1720 1774 1938

28- 56 1274 1388 1554 1858 2070 2451

Total feed 56- 84 1195 1427 1444 2025 2170 2564
consumption, kg
84-112 1040 1274 1405 1973 2067 2333

112-128 591 725 864 1030 1090 1116


5237 6121 6585


0-128


8606 9171 10420














TABLE 15. continued


Item Time Corn NBR BR Corn NBR .BR
In days restricted restricted restricted ad libitum ad libitum ad libitum


0- 28 10.27 9.61. 12.26 4.88 6.51 7.19

28- 56 4.22 6.38 8.35 4.91 6.25 7.26

Feed efficiency, 56- 84 6.76 6.11 7.07 7.39 8.04 13.85
kg,'feed/kg gain
84-112 9.96 9.59 17.78 8.70 12.15 13.54

112-128 3.82 12.30 7.05 8.38 7.40 16.34

0-128 6.16 7.98 9.41 6.31 7.62 10.03

aCorn is corn diet.
NBR Is non-bird-resistant sorghum grain diet.
BR is bird-resistant sorghum grain diet.







TABLE 16. CARCASS SPECIFIC GRAVITY, BODY SPECIFIC GRAVITY, BODY WATER, BODY FAT, AND BODY PROTEIN
DETERMINED FROM STEERS FED CORN, NON-BIRD-RESISTANT AND BIRD-RESISTANT SORGHUM GRAIN DIETS
DURING NET ENERGY STUDYa


Lot Animal Carcass Body Body Body Body
brand no. slaughter specific gravity specific gravity water fat protein
no.
% ~% %
04 1.0455 1.0394 52.53 25.52 17.63

112 1.0385 1.0325 50.20 28.68 16.96

Control 111 1.0424 1.0364 51.52 26.86 17.42

52 1.0411 1.0351 51.08 27.45 17.30

20 1.0563 1.0502 56.11 20.96 18.42

559 1.0443 1.0383 52.16 26.01 17.59

70 100 1.0519 1.0458 54.66 22.76 18.14

92 101 1.0516 1.0455 54.56 22.89 18.11

72 102 1.0474 1.0413 53.16 24.69 17.79

Corn 30 103 1.0417 1.0357 51.28 27.18 17.29
restricted
76 104 1.0359 1.0299 49.31 29.94 16.62

06 105 1.0615 1.0554 57.81 18.93 18.68

41 106 1.0568 1.0507 56.27 20.79 18.42


54.16 23.40 18.02


66 107


1.0504 1.0443






TABLE 16. continued


Lot Animal Carcass Body Body Body Body
brand no. slaughter specific gravity specific gravity water fat protein
no.

36 99 1.0450 1.0359 52.36 25.75 17.58

107 116 1.0593 1.0532 57.09 19.78 18.58

555 117 1.0459 1.0398 52.66 25.34 17.72
Non-bird- 40 118 1.0570 1.0509 56.34 20.69 18.45
resistant
restricted 106 119 1.0423 1.0363 51.49 26.89 17.36

12 120 1.0606 .1.0545 57.51 19.27 18.65

65 122 1.0500 1.0349 54.03 23.57 17.99

18 123 1.0453 1.0392 52.46 25.61 17.61

560 124 1.0406 1.0399 52.69 25.31 17.67

62 125 1.0542 1.0481 55.42 21.81 18.29

82 126 1.0599 1.0538 57.29 19.54 18.61

Bird-resistant 49 127 1.0589 1.0528 56.96 19.93 18.56
restricted
86 128 1.0464 1.0403 52.83 25.14 17.69

105 129 1.0621 1.0560 58.00 18.71 18.71

549 130 1.0545 1.0484 55.52 21.68 18.31


56.60 20.38 18.54


564 131


1.0578 1.0517






TABLE 16. continued


Lot Animal Carcass Body Body Body Body
brand no. slaughter specific gravity specific gravity water fat protein
no.

79 140 1.0386 1.0326 50.23 28.63 16.98

553 141 1.0277 1.0217 46.49 34.10 15.59

561 142 1.0422 1.0362 51.45 26.96 17.39

Corn ad llbitum 08 143 1.0324 1.0264 48.12 31.65 16.25

99 144 1.0264 1.0204 46.04 34.76 15.42

50 145 1.0368 1.0308 49.62 29.48 16.79

119 146 1.0506 1.0445 54.23 23.32 18.03

55 147 1.0419 1.0359 51.35 27.10- 17.31

26 97 1.0263 1.0203 46.01 34.81 15.40

11 132 1.0292 1.0232 47.01 33.30 15.77

Non-bird- 21 133 1.0279 1.0219 46.56 33.96 15.65
resistant
ad libltum 09 134 1.0526 1.0465 54.89 22.86 18.18

16 135 1.0470 1.0409 53.03 24.86 17.76

59 136 1.0325 1.0265 48.15 31.62 16.25

46 138 1.0434 1.0374 51.86 25.41 17.45


47.43 32.66 15.99


53 139


1.0304 1.0244












TABLE 16. continued


Lot Animal Carcass Body Body Body Body
brand no. slaughter specific gravity specific gravity water fat protein
no.


96 108 1.0427 1.0367 51.62 26.73 17.39

07 109 1.0316 1.0256 47.84 32.06 16.14

Bird-resistant 19 110 1.0418 1.0358 51.32 27.13 17.31
ad libitum
22 111 1.0439 1.0379 52.02 26.19 17.50

83 112 1.0390 1.0330 50.37 28.32 17.12

117 113 1.0534 1.0473 55.15 22.14 18.24

101. 114 1.0290 1.0230 46.94 33.39 15.80

75 115 1.0527 1.0466 54.92 22.43 18.19

aCarcass specific gravity was determined but all other values were calculated as outlined according to
Lofgreen and Garrett (1968).









LITERATURE CITED


Ammerman, C. B., L. R. Arrington, R. L. Shirley and G. K. Davis. 1964.
Comparative effects of fluorine from soft phosphate, calcium fluoride
and sodium fluoride on steers. J. Anim. Sci. 23:409.

Ammerman, C. B., R. M. Forbes, U. S. Garrigus, A. L. Neuman, H. W. Worton
and E. E. Hatfield. 1957. Ruminant utilization of inorganic phos-
phates. J. Anim. Sci. 16:796.

Anderson, R., E. Cheng and W. Burroughs. 1956. A laboratory technique
for measuring phosphorus availability of feed supplements fed to
ruminants. J. Anim. Sci. 15:489.

Anonymous. 1967. Evaluation of bentonite in a high concentrate finishing
ration for steers. News from American Colloid Company.

Anonymous. 1969. Bird-resistant milo and wheat in high concentrate steer
fattening rations. Feedstuffs 41(19):50.

A.O.A.C. 1970. Official Methods of Analysis (llth ed.) Association of
Official Agricultural Chemists, Washington, D. C.

Betrand, J. E., L. S. Dunavin and M. C. Lutrick. 1970. Comparative value
of corn and sorghum, both fed as high-moisture and dry grain for
finishing beef steers. West Fla. Exp. Sta. Mimeo. Report 70-1.

Bertrand, J. E., and M. C. Lutrick. 1971. Feeding value of NBR (non-
bird-resistant) and BR (bird-resistant) sorghum grain in the ration
of beef steers. Soil and Crop Sci. Soc. Fla., Proc. 31:24.

Blaxter, K. L. 1956. The nutritive value of feed as sources of energy.
J. Dairy Sci. 39:1396.

Blaxter, K. L. 1962. The Energy Metabolism of Ruminants. Charles C.
Thomas, Springfield, Illinois.

Blaxter, K. L., and J. A. F. Rook. 1953. The heat of combustion of the
tissues of cattle in relation to their chemical composition. Brit.
J. Nutr. 7:83.

Bratzler, J. W., and E. B. Forbes. 1940. The estimation of methane
production by cattle. J. Nutr. 19:611.

Brethour, J. R., and W. W. Duitsman. 1961. Value of ensiled high-
moisture sorghum grain (ground and unground) in a fattening ration
for yearling steers. Kan. Agr. Exp. Sta. Circ. 382.








Briggs, G. M., and M. R. S. Fox. 1956. Vitamin A deficiency in chicks
produced by adding high levels of bentonite to synthetic diets.
Poul. Sci. 35:570.

Bringe, A. N., and L. H. Schultz. 1969. Effects of roughage type or
added bentonite in maintaining fat test. J. Dairy Sci. 52:465.

Brown, G. W., A. D. Tillman and R. Totusek. 1968. Digestibility,
nitrogen retention and energy value of sorghum grains and corn
rations at three levels of intake. J. Anim. Sci. 27:170.

Brown, W. H., J. W. Stull, F. 0. Dafciala and P. W. Riley. 1966.
Comparison of milo and barley for lactating cows. J. Dairy Sci.
49:386.

Brown, W. H., L. M. Sullivan, L. F. Cheatham, K. J. Halback and J. W.
Stull. 1970. Steam processing versus pelleting of two rations of
milo and barley for lactating cows. J. Dairy Sci. 53:1448.

Buchanan-Smith, J. G., R. Totusek and A. D. Tillman. 1968. Effects of
method of processing on digestibility and utilization of grain
sorghum by cattle and sheep. J. Anim. Sci. 27:525.

Burkitt, H. N. 1969. Sodium bentonite addition to high concentrate
pelletted rations self-fed to finishing yearling cattle.
Feedstuffs 41(45):32.

Burns, R. E. 1963. Methods of tannin analysis for forage crop
evaluation. Univ. of Georgia Tech. Bull., N.S. 32.

Cadena, M., W. H. Hale, F. Hubbert and B. Taylor. 1962. Digestibility
of dry0rolled milo and steam-rolled barley by fattening steers.
Ariz. Cattle Feeders Day.

Cardon, B. D. 1964. High energy fattening rations. Washington Cattle
Feeders Association 6th Ann. Conference.

Deis, P., and M. W. Sanchez. .1964. Clarification of wines, using a
bentonite-casein mixture and a bentonite-gelatin mixture. Chemical
Abstracts 61:1000 4-h.

Driedger, A., and J. K. Riggs. 1972. Hybrid by location effect on
S digestibility of grain. J. Anim. Sci. 35:263 (Abstr.).

Durham, R. M., G. F. Ellis and B. Cude. 1967. A comparison of flaked,
popped and cracked milo in all concentrate ration. J. Anim. Sci.
26:220 (Abstr.).

Ellis, G. E., and J. A. Carpenter. 1966. Popped milo in fattening
rations for beef cattle. J. Anim. Sci. 25:594 (Abstr.).

Eng, K. S., B. E. Jeter, M. E. Riewe and L. H. Breuer. 1965. Utilization
of sorghum grain protein as affected by variety and fertilization.
J. Anim. Sci. 24:880 (Abstr.).







52


Erwin, E. S., C. J. Elam and I. A. Dyer. 1957. The influence of sodium
bentonite in vitro and in the ration of steers. J. Anim. Sci. 16:858.

Eudaly, R. M., and J. K. Riggs. 1969. Energy value of sorghum grain
processed four ways. J. Anim. Sci. 29:157 (Abstr.).

Filippov, A. M., and G. G. Vaiuiko. 1970. Changes in the color of red
table wines. Chemical abstracts 73:13128.

Fox, D. G., E. W. Klosterman, H. W. Newland and R. R. Johnson. 1970.
Net energy of corn and bird-resistant grain sorghum rations for
steers when fed as grain or silage. J. Anim. Sci. 30:303.

Franks, L. G., J. R. Newsom, R. E. Renbarger and R. Totusek. 1972.
Relationship of rumen volatile fatty acid to type of grain sorghum
processing method and feedlot performance. J. Anim. Sci. 35:404.

Furr, R. D., and L. B. Sherrod. 1968. Variation in protein and mineral
content of grain sorghum. J. Anim. Sci. 27:1113 (Abstr.).

Garrett, W. N. 1958. The comparative energy requirements of sheep and
cattle for maintenance and gain. Ph.D. Thesis. Univ. of Calif.

Garrett, W. N. 1965. Comparative feeding value of steam-rolled or ground
barley and milo for feedlot cattle. J. Anim. Sci. 24:726.

Garrett, W. N., G. P. Lofgreen and J. H. Meyers. 1964. A net energy
comparison of barley and milo for fattening cattle. J. Anim. Sci.
23:470.

Hale, W. H., B. Theurer, B. Taylor and H. Essig. 1968. Cattle Feeders
Day Rept., Arizona Agr. Exp. Sta.

Hale, W. H., L. Cuitain, W. J. Saba, B. Taylor and B. Theurer. 1966.
Effect of steam processing and flaking milo and barley on performance
and digestion by steers. J. Anim. Sci. 25:392.

Hall, G. A. B., C. W. Absher, R. Totusek and A. D. Tillman. 1968. Net
energy of sorghum grain and corn for fattening cattle. J. Anim. Sci.
27:165.

Harvey, U. R. 1960. Least-square analysis of data with unequal subclass
numbers. Agriculture Res. Service, ARS20-8.

Nenderson, G. H., and L. H. Greuer. 1969. True digestibility of sorghum
grain amino acids in cattle rations. J. Anim. Sci. 29:161 (Abstr.).

Hillis, W. G. 1968. Nitrogen and phosphorus supplements for ruminant
rations high in dried citrus pulp. M.S. Thesis, Univ. of Fla.,
Gainesville.

Hinders, R. C., and K. Eng. 1971. Starch availability of various grain
sorghums. J. Anim. Sci. 33:339 (Abstr.).








Hobbs, C. S., R. P. Moorman, J. M. Griffith, J. L. West, G. M. Merriman,
S. L. Hansard and C. C. Chamberlain. 1954. Fluorosis in cattle
and sheep. Univ. of Tennessee Bull., 235.

Holmes, J. H. G., M. J. Drennan and W. W. Garrett. 1970. Digestion of
steam-processed milo by ruminants. J. Anim. Sci. 31:409.

Husted, W. T., S. Mehan, W. H. Hale, M. Little and B. Theurer. 1968.
Digestibility of milo processed by different methods. J. Anim.
Sci. 27:531.

Keating, E. K., W. J. Saba, W. H. Hale and B. Taylor. .1965. Further
observation on the digestion of milo and barley by steers and lambs.
J. Anim. Sci. 24:1080.

Kiesling, H. E., J. E. McCroskey and D. G. Wagner. 1971. Effect of milo
preparation on energy utilization. J. Anim. Sci. 33:345 (Abstr.).

Klieber, M. 1961. The Fire of Life. John Wiley and Sons, Inc., New York
and London.

Kraybill, H. F., H. L. Bitter and 0. G. Hankins. 1952. Body composition
of cattle. II. Determination of fat and water content from measure-
ment of body specific gravity. J. Appl. Physiol. 4:575.

Kuhlman, R. L., M. R. Karr, R. E. White and D. E. Hodge. 1968. Dry rolled
vs. steam flaked milo with 13% and 5% roughage in cattle finishing
rations. J. Anim. Sci. 27:1769 (Abstr.).

Lane, G. T., R. E. Leighton and D. H. Bade. 1972. In vitro evaluation
of chemically reconstituted sorghum grain. J. Dairy Sci. 55:328.

Lofgreen, G. P. 1960. The availability of the phosphorus in dicalcium
phosphate, bone meal, soft phosphate and calcium phylate for mature
wethers. J. Nutr. 70:58.

Lofgreen, G. P., D. L. Bath and H. T. Strong. 1963. Net energy of
successive increments of feed above maintenance for beef cattle. J.
Anim. Sci. 22:598.

Lofgreen, G. P., and W. N. Garrett. 1968. A system for expressing net
energy requirements and feed values for growing and finishing beef
cattle. J. Anim. Sci. 27:793.

Lofgreen, G. P., L. H. Hull and K. K. Otagaki. 1962. Estimation of empty
body weight of beef cattle. J. Anim. Sci. 21:20.

Lofgreen, G. P., and K. K. Otagaki. 1960. The net energy of blackstrap
molasses for fattening steers as determined by a comparative
slaughter technique. J. Anim. Sci. 19:392.

Long, T. A., A. D. Tillman, A. B. Nelson, B. Davis and W. D. Gallup. 1956.
Dicalcium phosphate and soft phosphate with colloidal clay as sources
of phosphorus for beef heifers. J. Anim. Sci. 15:1112.








Martin, L. C. 1967. Sodium bentonite in .urea-containing rations for
ruminants. M.S. Thesis, Ok. State Univ., Stillwater.

Martin, L. C., A. J. Clifford and A. D. Tillman. 1969. Studies on
sodium bentonite in ruminant diets containing urea. J. Anim.
Sci. 29:777.

McCollough, R. L., J. C. Riley, C. L. Drake and B. E. Brent. 1972a.
Digestibility of seven hybrid grain sorghums and two hybrid corns.
J. Anim. Sci. 35:270. (Abstr.).

McCollough, R. L., J. C. Riley, C. L. Drake and B. E. Brent. 1972b.
Feeding value of seven hybrid grain sorghums and two hybrid corns.
J. Anim. Sci. 35:270. (Abstr.).

McGinty, D. D., and J. K. Riggs. 1968. Variation in digestibility of
sorghum grain varieties. J. Anim. Sci. 27:1170. (Abstr.).

McGinty, D. D., J. K. Riggs and H. 0. Kunkel. 1969. Factors affecting
in vitro digestibility of sorghum grain. J. Anim. Sci. 29:165.
FA b-TTr.T.

McNeill, J. W.\, G. D. Potter and J. K. Riggs. 1971. Ruminal and post-
ruminal carbohydrate utilization in steers fed processed sorghum
grain. J. Anim. Sci. 33:1371.

Mendel, V. E. 1971. Montmorillonite clay in feedlot rations. J. Anim.
Sci. 33:891.

Morrison, R. T., and R. N. Boyd. 1970. Organic Chemistry (2nd ed.).
Allyn and Bacon, Inc. Boston, Massachusetts.

National Research Council. 1970. Nutrient requirements of domestic
animals. No. 4. Nutrient requirements of beef cattle. National
Academy of Science, Washington, D. C.

Neuhaus, V., and R. Totusek. 1971. Factors affecting the in vitro
digestibility of high moisture sorghum grain. J. Anim. Sci. 33:1321.

Newsom, J. R., R. Totusek, R. Renbarger, E. C. Wilson, L. Franks, V.
Neuhaus and W. Basler. 1968. Methods of processing milo for
fattening cattle. Okla. Agr. Exp. Sta. Misc. Pub. 80.

Newland, H. W., E. W. Klosterman and D. G. Fox. 1970. Bird-resistant
grain sorghum vs. corn for finishing cattle. J. Anim. Sci. 31:
128. (Abstr.).

Nishimuta, J. F., L. B. Sherrod and R. D. Furr. 1969. Digestibility of
regular, waxy and white sorghum grain rations by sheep. J. Anim.
Sci. 28:860.

Osman, H. F., B. Theurer, W. H. Hale and S. M. Mehan. 1970. Influence
of grain processing on In vitro enzymatic starch digestion of
barley and sorghum grain. J. Nutr. 100:1133.








Perry, T. W., R. C. Peterson, M. T. Mohler and W. M. Beeson. 1968.
Bentonite as an additive to high urea supplement for high energy beef
cattle rations. Incomplete Data, Annual Indiana Cattle Feeders Day.

Popova, Y. G. 1962. The absorption and desorption of vitamin B12 on
active clays. Chemical Abstracts 52:4768c.

Potter, G. D., J. W. McNeill and J. K. Riggs. 1971. Utilization of
Processed sorghum grain proteins by steers. J. Anim. Sci. 32:540.

Pund, W. A. 1970. Finishing yearling steers with high energy grain sorghum
silage. Miss. State Univ. Agr. Exp. Sta. Bull. 780.

Ralston, A. T., D. C. Church, W. H. Kennick and N. 0. Taylor. 1963.
Effect of varying milo-barley levels, ration preparation and intra-
ruminal injection of vitamin A upon feedlot performance of steers.
J. Anim. Sci. 22:943.

Reid, J. T., G. H. Wellington and H. 0. Dunn. 1955. Some relationships
among the major chemical components of the bovine body and their
application to nutritional investigations. J. Dairy Sci. 38:1344.

Riggs, J. K., and D. D. McGinty. 1970. Early harvest and reconstituted
sorghum grain for cattle. J. Anim. Sci. 31:991.

Riggs, J. K., J. W. Sorenson, J. L. Adame and L. M. Schake. 1970.
Popped sorghum grain for finishing beef cattle. J. Anim. Sci. 30:634.

Rindsig, R. B., and L. H. Schultz. 1970. Effect of bentonite on nitrogen
and mineral balances and ration digestibility of high-grain rations
fed to lactating dairy cows. J. Dairy Sci. 53:888.

Rindsig, R. 8., L. H. Schultz and G. E. Shook. 1969. Effects of the
addition of bentonite to high-grain dairy rations which depress milk
fat percentage. J. Dairy Sci. 52:1770.

Saba, W. J., W. H. Hale, F. Hubbert, J. Kiernat and B. Taylor. 1964.
Digestion of milo and barley by cattle. J. Anim. Sci. 23:533.

Samford, R. A., G. D. Potter, L. W. Rooney and J. K. Rtggs. 1970a.
Digestibility of sorghum grains from the world collection. J. Anim.
Sci. 30:327 (Abstr.).

Samford, R. A., J. K. Riggs, L. W. Rooney and J. C. Coon. 1970b. Ruminal
digestibility of sorghum endosperm types. J. Anim. Sci. 30:1038
(Abstr.).

Schuh, J. D., W. H. Hale and B. Theurer. 1971. Pressure cooking versus
steam processing and flaking sorghum grain for dairy calves. J.
Dairy Sci. 54:401.

Sherrod, L. B., R. C. Albin and R. D. Furr. 1969. Net energy of regular
and waxy sorghum grains for finishing steers. J. Anim. Sci. 29:997.



















Sherrod, L. B., and R. D. Furr. 1970. Sheep digestibility of rations
containing sorghum grain produced with different nitrogen
fertilization rates. J. Anim. Sci. 30:1042 (Abstr.).

Taylor, B., F. Hubbert, C. B. Roubicek, R. E. Taylor, E. B. Stanley and
E. H. Hussmann. 1960. Steam-rolled vs. dry-rolled milo and barley.
Arlz. Cattle Feeders Day.

Tommeroik, R. S., and D. E. Waldern. 1969. Comparative feeding value
of wheat, corn, barley, milo, oats and a mixed concentrate ration
for lactating cows. J. Dairy Sci. 52:68.

Valuiko, G. G., and A. 1. Ivanyutina. 1970. Red wines. Chemical
Abstracts 72:224.

VanSoest, P. J. 1969. The chemical basis for the nutritive evaluation
of forages. Proc. of the National Conference on Forage Quality
Evaluation and Utilization.

Vetter, R. L., N. Gay, F. H. McGuire and F. Ransom. 1968. Further studies
on the use of bentonite in ground ear corn-high urea rations for
steers. Iowa State Univ. A.S. RI10.

Vetter, R. L., N. Gay and F. Ransom. 1967. Evaluation of bentonite in a
high-concentrate finishing ration for steers. Iowa State Univ. A.S.
R98.

Withers, F. T., P. J. Patrick, W. A. Pund and H. W. Essig. 1969.
Utilization of bird-resistant and non-bird-resistant milo silage.
J. Anim. Scl. 28:127. (Abstr.).

Wise, M. B., R. A. Wentworth and S. E. Smith. 1961. Availability of the
phosphorus in various sources for calves. J. Anim. Sci. 20:329.









BIOGRAPHICAL SKETCH

William Edwin Maxson was born in Turlock, California, on

October 4, 1947. His family moved to Delano, California soon

afterward, where he attended public school and graduated from

Delano High School in 1965. Next he was accepted by California

State Polytechnic College where he majored in Animal Husbandry

and graduated with the degree of Bachelor of Science in Agriculture

in June of 1969. While in attendance at California State Polytechnic

College the author served as President of Boots and Spurs as well as

the Collegiate 4-H Club. In September, 1969, he entered graduate

school at the University of Florida where he graduated with the

degree of Master of Science in Agriculture In August, 1971. He

continued his education at the University of Florida where he is now

a candidate for the degree of Doctor of Philosophy in Animal Science.

William Edwin Maxson is a member of Gamma Sigma Delta, the

Honor Society of Agriculture, and the Society of Sigma Xi. He

married Joann Lee Pederson of Los Altos, California, in August, 1969.









I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate,in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.




Ra~L. Shirley, Ch rman
Professor of Animal Nutrition



I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate,in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.




Clarence B. Ammerman
Professor of Animal Nutrition



I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate,in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.




e E. Bertrand
sociate Professor of Animal Science



I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully.
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.




PTony J.u A
Profes r Animal Science








I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.




Edward M. Hoffman/ /
Associate Professor microbiology



I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.




Richard H. House
Assistant Professor of Animal Science



I certify that I have read this study and that in my opinion it
conforms to acceptable standards of scholarly presentation and is fully
adequate, in scope and quality, as a dissertation for the degree of
Doctor of Philosophy.




Arno Z. P Imer
Professor of Meat Science



This dissertation was submitted to the Dean of the College of
Agriculture and to the Graduate Council, and was accepted as partial
fulfillment of the requirements for the degree of Doctor of
Philosophy.

March, 1973


wan, College of Agri ultur


Dean, Graduate School




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