Group Title: Department of Animal Science mimeograph series - Florida Agricultural Experiment Station ; AN67-4
Title: The effect of method of processing on nutritive value of corn for fattening cattle
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 Material Information
Title: The effect of method of processing on nutritive value of corn for fattening cattle
Series Title: Department of Animal Science mimeograph series
Physical Description: 11 p. : ; 28 cm.
Language: English
Creator: Hentges, J. F ( James Franklin ), 1925-
University of Florida -- Dept. of Animal Science
University of Florida -- Agricultural Experiment Station
Publisher: Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1966
Subject: Cattle -- Feeding and feeds -- Florida   ( lcsh )
Corn as feed -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
Bibliography: Includes bibliographical references (p. 4-5).
Statement of Responsibility: J.F. Hentges, Jr. ... et al..
General Note: Caption title.
General Note: "October, 1966."
 Record Information
Bibliographic ID: UF00072982
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 78592799

Full Text
/7^ 3 4 /nr
ANv 67-/

Department of Animal Science Florida Agricultural
Mimeograph Series AN67-4 Experiment Station
October, 1966 Gainesville, Florida


J. F. Hentges, Jr., M. T. Cabezas./, J. E. Moore
J. W. Carpenter and A. Z. Palmer
Florida Agricultural Experiment Stations- Gainesville

A need for increasing efficiency of feed utilization plus an increased usage
of shelled corn for fattening cattle has stimulated research on different methods
of processing corn. Diets containing flaked (steamed rolled) corn are reported
to be most efficiently utilized (Shaw et al., 1960; Arnett and Bradley, 1961; New-
land et al., 1962). Variable results have been reported with pelleted high con-
centrate diets largely due to depression of feed intake (Beardsley et al., 1959;
Cullison,, 1961; Davis et al., 1963; McCroskey et al., 1961). The different methods
of flaking and pelleting and the different proportions of corn in the diets used
in these studies make it difficult to evaluate and compare their results.

This investigation compared feedlot performance, carcass characteristics and
ruminoreticulum features of beef steers fed diets containing corn processed by four
different methods.

Experimental Procedure

Two feeding experiments were conducted during a two-year period with 160 year-
ling steers. In Experiment I, 40 Hereford and 40 Hereford x Brahman yearling steers
were equally allotted to four treatments on basis of weight, grade and breed. In
Experiment II, 80 Hereford steer calves were allotted similarly. Each steer was
drenched with 5 oz. phenothiazine and was given a 24 mg. diethylstilbestrol ear im-
plant. They were kept in open dry lots where they had free access to water, shade
and a trace mineralized salt mixture. The experimental diets were self-fed for 84
days in Experiment I and 126 days in Experiment II. In Experiment I, the steers
were gradually changed from a roughage diet to the experimental concentrate diets
during a 28-day preliminary period for which data are not reported. In Experiment
II, steers which previously had been fed concentrates on pasture were allowed free
access to self-feeders containing experimental diets from the start of the 126-day
feeding period. Low quality grass hay was offered ad libitum in both experiments.
Observations were made daily for digestive disorders.

Composition of the diets is given in Table 1. The physical forms of yellow
shelled corn used in the four diets were ground, cracked, flaked and pelleted. The
ground corn had been hammermill ground through a 3/8 in. screen. The cracked corn
had been cold cracked and the siftings (hominy feed) from cracking were not included
in the diet. Flaked corn had been cracked, steamed for 10 min. to a temperature of

1/ Florida Agricultural Experiment Station Journal Series No. 1890.
2/ Present address: Departamentode Ciencias Biologicas, Universidad de El Salva-
dor, San Salvador, El Salvador, C. A.
3/ Department of Animal Science.
4/.Assistance of Florida Feed Mills, Inc., Jacksonville, Fla. and Norris Cattle Co.,
Ocala, Fla. is acknowledged.


190oF and moisture content of 17%, rolled with a 0.01 in. roll spacing and dried to
13% moisture. Siftings from cracking and drying were not included in the diet. The
fourth diet was the same as the ground corn diet except that it had been steam-pelleted
using a 1/4 in. die. In Experiment II, the proportion of corn in the diets was re-
duced from 80% to 72% and 10% ground corn cobs was added. In addition, 1.0% urea was
substituted for 1.5% of cottonseed meal and 1.5% of soybean oil meal. Proximate analy-
ses of diets were conducted according to AOAC (1960) methods and are shown in Table 1.

The cattle were weighed individually at the beginning and at 28-day intervals.
Final weights recorded at the feedlot were used to calculate average daily gains. In
Experiment II, average daily gains were also calculated on an empty body weight basis.
The latter was obtained by subtracting weights of the ruminoreticulum contents from
the liveweight taken just before slaughtering.

Sections of the rumen wall were removed from the anterioventral part of the dor-
sal sac for observations on the mucosa.

Carcass weights were recorded before and after a 48-hr. chilling period. The
carcasses were evaluated for USDA carcass grade and estimated yield of lean cuts by
federal graders. Ribeye area was measured at the 13th rib on the right side of each

Results and Discussion

Data on gains, feed intake and efficiency of feed utilization are presented in
Tables 2 and 3. In Experiment I, the groups fed ground, flaked and pelleted corn had
identical average daily gains of 3.3 lb. The group fed cracked corn gained an average
of 0.3 lb. less per day and this was attributed to sifting of the fine ingredients
which constituted a large portion of the protein needed for a balanced nutrient intake.
A smaller degree of sifting was also observed in the diet containing flaked corn. To
lessen this problem in Experiment II, 10% ground corn cobs and 1% urea were used in
the formulae and siftings were removed daily to assure a supply of fresh feed in the
self-feeders. By doing this, gains of steers fed cracked corn equalled those of the
steers fed ground corn and gains of steers fed flaked and pelleted corn diets slightly
exceeded those of the other two lots.

Table 3 shows that average daily gains calculated on an empty body weight basis
did not change the interpretation of the results obtained in Experiment II. Lofgreen
et al. (1962) proposed a method for estimation of empty body weight of cattle from
warm carcass weight by means of a regression equation. To test that method, the rela-
tionship between empty body weight and warm carcass weight was determined from data
obtained in Experiment II. The regression equation is Y = 31 + 1.47X, where Y is
empty body weight and X is warm carcass weight. The correlation coefficient was 0.92
and the standard error of the estimate was 30 or approximately 3% of the empty body
weight of 903 lb. The correlation coefficient obtained in this study, 0.92, was lower
than the 0.97 coefficient reported by Lofgreen et al. (1962). Under these circum-
stances, the use of empty body weight calculated from warm carcass weight by means of
the regression equation given above had no advantage over using final liveweight as
the basis for comparing treatment effect on body weight gain.

In Experiment I, average daily feed intake was identical for steers on the flaked
and pelleted corn diets but was 1.9 and 2.4 lb. less than for cracked and ground diets


respectively. In Experiment II, the average daily intake of feed and the average
daily concentrate intake of the pelleted and flaked corn diets was slightly higher
than in the group fed ground corn. The inclusion of ground corn cobs and urea in
the diet apparently eliminated the negative effect that pelleting had on intake.
Hay consumption was consistently lowest in the group fed flaked corn. This may have
been due to the different physical characteristics imparted to that diet by flaked
corn. As shown in Table 4, the flaked corn diet weighed 7 lb. less per cubic foot
than the other diets. This represents an increase of 18% in volume which may have
substituted for some of the bulkiness provided by hay in the other diets.

Efficiency of feed utilization in both experiments was superior for steers fed
the diet containing flaked corn. An average of the two experiments shows that flak-
ing produced an increase in feed efficiency of 5% over the pelleted diet and of 10
to 15% over the diets containing ground and cracked corn. These results agree with
those reported by Arnett and Bradley (1961), Shaw et al.(1960) and Newland et al.
(1962). The advantage in feed efficiency of the diet containing flaked corn over
diets containing ground or cracked corn may have been due to alterations of starch,
protein or other nutrients. Steaming and rolling during the process of flaking is
reported to cause a rupture of the starch granule and partial dextrinization of the
starch, making it more available to the action of bacterial amylase enzymes in the
rumen (Nasr, 1950). In turn, this promotes a different type of rumen fermentation
which ?hillipson (1952) reported to be the cause of a lowered acetate to propionate
ratio. Armstrong et al. (1957b) found that a lowered acetate to propionate ratio
was favorable for energy utilization in ruminants because of a lowered heat incre-
ment. Increases in feed efficiency obtained by other researchers with pelleted diets
containing a high proportion of ground corn has also been attributed to an altered
rumen fermentation due to physical and chemical changes produced in the feed by pel-
leting (Ensor et al., 1959; Rhodes and Woods, 1962).

Tables 5 and 6 show that the different diets produced no significant differences
among dietary treatments for dressing percentage, USDA carcass grade, estimated car-
cass yield, conformation score and marbling score.

In Table 7, adjusted ruminoreticulum weights (ruminoreticulum wt. per 100 lb.
empty body wt.) and the color of rumen papillae from steers in Experiment II are
presented. Ruminoreticulums from steers. fed the flaked and pelleted corn diets were
heaviest. This was indicative of a heavier mucosa of the rumen wall and was associa-
ted with a slightly higher average daily gain and a superior feed efficiency. Sin-
clair and Kunkel (1959) and Kunkel et al. (1962) have reported that ruminoreticulum
color and weight were correlated with rate of gain in lambs. Jensen et al. (1958)
reported that lambs with abnormal rumen mucosa, called "rumen parakeratosis", did
not gain as rapidly as similarly fed lambs without this rumen disorder. In this
study the condition of the rumen mucosa did not have an apparent harmful effect on
gains or feed efficiency.

Differences were observed in color and shape of papillae in the cranial sac of
the rumen. Papillae from steers fed the pelleted diet were mostly dark gray and black
with irregular shapes in contrast to lighter colored, normally shaped papillae from
steers fed the other diets. This condition was similar but not as extreme as that
reported by Cullison (1961) with steers fed pelleted diets containing 50% corn and
30% hay plus supplement.

Although flaking (steaming, rolling and drying) of corn has become popular for


the purposes of weed seed sterilization and conversion of the hard-coated hybrid corn
kernel into an attractive, non-floury flake, it appears that this process may also
impart the added advantages of increasing efficiency of utilization (when properly
flaked) and reducing the need for "bulky ingredients" in diets where "sifting" of in-
gredients is controlled. For bulk handling and mechanical self-feeding, steam pellet-
ing offers obvious advantages provided diets can be formulated to insure against a
decrease in consumption.


Two experiments were conducted with yearling steers to measure the effect of
method of processing corn diets on feedlot performance and carcass characteristics of
fattening cattle. Ground, cracked or flaked corn was used in three of the diets while
the fourth containing ground corn was pelleted. Poor quality hay was offered ad libi-

Efficiency of feed utilization was highest in steers fed flaked and pelleted
corn diets. The improved feed efficiency obtained with flaked corn was partly due to
bulkiness which reduced the hay intake in comparison.with other diets. The relative
daily intake of the pelleted diet was increased by adding ground corn cobs and urea to
the formula.

Ruminoreticulums from steers fed flaked corn and pelleted diets were heavier
than those of steers fed ground and cracked corn diets.

Papillae in the rumens of steers fed the pelleted diet were dark gray or black
but this condition apparently did not affect gains or feed efficiency.

The different methods of processing the corn diets had no significant effect on
rate of gain or the carcass characteristics which were studied..

Literature Cited

1. A.O.A.C. 1960. Official Methods of Analysis (9th ed.). Association of Official
Agricultural Chemists. Washington, D. C.

2. Armstrong, D. G.,:K. L. Blaxter and N. McC. Graham. .1957. The heat increments
.of mixtures of steam-volatile fatty acids in fasting sheep. Brit. J. Nutr.

3. Arnett, D. W. and N. W. Bradley. 1961. Effects of pelleted, flaked and ground
corn and pelleted distillers dried grains with solubles on digestibility of
fattening rations and feedlot performance of beef steers. J. Animal Sci.
20:396. (Abstr.)
4. Beardsley, D. W., W. C. McCormick and B. L. Southwell. 1959. Steer performance
on and rumen effects of different concentrate roughage ratios in pelleted and
unpelleted mixed fattening rations. J. Animal Sci. 18:1507 (Abstr.)


5. Cullison, A. E. 1961. Effect of physical form of the ration on steer perfor-
mance and certain rumen phenomena. J. Animal Sci. 20:478.

6. Davis, R. E., R. R. Oltjen and J. Bond. 1963. High.concentrate studies with
beef cattle. J. Animal Sci. 22:640.

7. Ensor, W. L., J. C. Shaw and H. F. Tellechea. 1959. Special diets for the pro-
duction of low fat milk and more efficient gains in body weight. J. Dairy Sci.

8. Jensen, R., J. C. Flint,.R. f. Udall, A. W. Deem andC. L. Seger. 1958. Paraker-
atosis of the rumens of lambs fattened on pelleted feed. Am. J. Vet. Res.

9. Kunkel, H. O., F. E. Tutt, J. C. Reagor, H. A. Glimp and J. D. Robbins. 1962.
Ruminal development of lambs related to rates of gain, anabolic estrogens,
antibiotics, hydroxyzine and terephthalic acid. J. Animal Sci. 21:681.

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

11. McCroskey, J. E., L. S. Pope, D. F. Stevens and G. Waller. 1961. Effect of pel-
leting steer fattening rations of different concentrate to roughage ratios.
J. Animal Sci. 20:42.

12. Nasr, H. 1950. Amylolytic activity in the rumen of the sheep. J. Agr. Sci.

13. Newland, H. W., W. T. Magee, 0. A. Branaman and L. H. Blakeslee. 1962. Effect
of heat-processing and pelleting corn for steers and lambs. J. Animal Sci.

14. Phillipson, A. T. 1952. The fatty acids present in the rumen of lambs fed on a
flaked maize ration. Brit. J. Nutr. 6:190.

15. Rhodes, R. W. and W. Woods. 1962. Volatile fatty acid measurements on the rumen
contents of lambs fed rations of various physical forms. J. Animal Sci. 21:

16. Sinclair, W. C. and H. 0. Kunkel. 1959. Variations in postweaning development
of ruminal mucosa in lambs. Proc. Soc. Exp. Biol. Med. 98:81.

17. Shaw, J. C., W. L. Ensor, H. F. Tellechea and S. D. Lee. 1960. Relation of
diet to rumen volatile fatty acids, digestibility, efficiency of gain and
degree of unsaturation of body fat in steers. J. Nutr. 71:203.

- 6 -


Composition I II

Ingredients, %
Yellow corn 80.0 72.0
Soybean oil meal, 44% 4.0 2.5
Cottonseed meal, 41% 4.0 2.5
Urea, 262% 0.0 1.0
Cane molasses, standard 5.0 5.0
Alfalfa meal, dehydrated 5.0 5.0
Corn cobs, ground 0.0 10.0
Mineral and vitamin mixa 2.0 2.0
Proximate analysis
Nitrogen, % 2.2 2.5
Ash, % 6.5 6.5
Ether extract; % 4.1 4.0
Crude fiber, % 5.6 5.8
Gross energy, Kcal./gm. 4.0 4.3

a Mineral mix contained 30% sodium chloride, 1.4% iron, 0.108%
copper, 0.104% cobalt .18.9% calcium, 5.5% phosphorus, 0.485%
manganese and 0.11% iodine. Vitamin mix contained 10,000 I.U.
vitamin D2 per lb. and was adjusted to provide an average in-
take of 20,000 I.U. vitamin A per day.
Moisture-free basis.

-7 -




Method of processing corn


Number of steers
Days fed
Av. initial wt., lb.
Av. final wt., lb.
Av. total gain, lb.
Av. daily gain, lb.
Av. daily feed intake,
Concentrate, lb.
Hay, lb.
Lb. feed per lb. gainb
Concentrate, lb.
Hay, lb.

Ground Cracked




Flaked Pelleteda



a -
Whole diet was pelleted

b Moisture-free basis

-- -



Method of processing corn
Item Ground Cracked Flaked Pelleteda

Number of steers 20 20 20 20
Days fed 126 126 126 126
Av. initial wt., lb. 583 585 577 588
Av. final wt., lb. 1066 1010 1029 1032
Av. total gain, lb. 418 425 452 444
Av. daily gain, lb. 3.3 3.4 3.6 3.5
Adjusted av. daily gain, Ib.b 2.4 2.5 2.7 2.6
Av. daily feed intake, lb.c 21.6 22.7 20.9 22.2
Concentrate, lb. 18.1 19.5 18.3 18.5
Hay, Ib. 3.5 3.2 2.6 3.7
Lb. feed per lb. gainc 6.7 6.7 5.8 6.3
Concentrate, lb. 5.5 5.8 5.1 5.3
Hay, lb. 1.0 0.9 0.7 1.0

a Whole diet was pelleted

b Calculated from empty body weight (liveweight before slaughtering
less ruminoreticulum contents)

c Moisture-free basis

-9 -


Method of Form of Density
processing diet lb./cu. ft.

Ground, 3/8" Meal 38
Cracked Meal 38
Flaked Meal 31 -
Pelleteda Pellet, 1/4" 37

a Whole diet was pelleted



Method of processing corn
Ground Cracked Flaked Pelleted4

Chilled carcass wt., lb. 698 672 687 699
Dressing per centb 59.1 59.0 59.8 60.9
USDA carcass grade 10.8 10.1 10.2 10.9
.Av. conformation saoxec ..11.7.- .. 11.3.... 10.9 11.7
Av. marbling score 10.4 7.3 8.7 10.4
Estimated carcass yield, % 48.0 48.5 48.4 47.8
Est. kidney and pelvic fat, % 5.1 5.0 5.0 5.3
Av. fat over ribeye, in. 0.7 '" 0-6 0.7 0.7
Av. ribeye area, sq. in. 12.6 12.6 12.8 12.7

a Whole diet was pelleted
b Based on chilled carcass weight over liveweight shrunk 3%
c Good = 10, high Good = 11 and low Choice = 12
d Slight plus = 7, slight minus = 8, small = 9, small plus = 10 and
modest minus = 11.

- 10 -


Method of processing corn
Ground. Cracked... Flaked Pelleteda

Chilled carcass wt., lb. 578 573 589 591
Dressing per centb' 60.9 60.4 61.4 60.9
USDA carcass grade 10.8 10.7 10.5 10.7
Av. conformation scorec' 10.8 10.7 10.6 10.8
Av. marbling scored 9.0 9.4 8.9 9.1
Estimated carcass yield,% ... 50.8 50.0 50.7 50.2
Est. kidney and pelvic-fat, %. -2.7 2.7 2.8 2.7
Av. fat over ribeye, in. .4 .5 .4 .4
Av. ribeye area, sq. in. 11.3 10.7 11.5 11.0

aWhole diet was pelleted

bBased on chilled carcass weight over liveweight shrunk 3%

c Good = 10, high Good = 11 and low Choice = 12

dSlight plus = 7, slight minus = 8, small = 9, small plus = 10 and
modest minus = 11

- 11 -


Method of processing corn
Ground Cracked Flaked Pelleteda

Av. wt. ruwinoreticulum/100 lb. 2.0 2.1 2.3 2.2
EBW, Ib.

Av. wt. ruminoreticulum contents, lb. 50.0 56.0 56.0 53.0

Papillae color, number

Dark gray or black 4 5 0 11

Medium to light gray 14 13 3 9

Flesh 2 1 17 0

a Whole diet was pelleted

b Empty body weight is liveweight before slaughtering less ruminoreticulum contents

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