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Title: Influence of summer pasture, diethylstilbstrol and shade on fattening cattle in south Florida
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Title: Influence of summer pasture, diethylstilbstrol and shade on fattening cattle in south Florida
Alternate Title: Bulletin 700 ; Florida Agricultural Experiment Station
Physical Description: Book
Language: English
Creator: Peacock, F. M.
Kirk, W. G.
Hodges, E. M.
Palmer, A. Z.
Carpenter, J. W.
Publisher: Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida
Publication Date: 1965
Copyright Date: 1965
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Bibliographic ID: UF00026905
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aep0066 - LTUF
18363306 - OCLC
000929287 - AlephBibNum

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BULLETIN 700 (TECHNICAL)
OCTOBER 1965





















F. M. PEACOCK

W. G. KIRK

E. M. HODGES

A. Z. PALMER 7

J. W. CARPENTER
\I/



Influence of Summer Pasture,

Diethylstilbestrol, and Shade on

Fattenin Cattle in South Florida




| 1l AGRICULTURAL EXPERIMENT STATIONS
Institute of Food and Agricultural Sciences
University of Florida, Gainesville
"- J.R. Beckenbach, Director













CONTENTS

Page
Introduction ----------------- ---------- 3
Review of Literature --------- ----------- 3
Experimental Procedures--- ------- ----- ---- 4
Pasture Versus Feedlot Plus Stilbestrol Versus
No Stilbestrol _------- ---- ------ 4
Pasture Versus Feedlot Plus Shade Versus No
Shade ----------------------------- 6
Results and Discussion------- ------------------------------------------------ 7
Results and Discussion 7
Pasture Versus Feedlot Plus Stilbestrol
Versus No Stilbestrol---------- --- ---- 7
Pasture Versus Feedlot Plus Shade Versus
No Shade 10
TDN Per 100 Pounds Gain From Concentrate for
Pasture and Feedlot Over the Seven-Year
Period ------------- 11
Summary and Conclusions --- --------------------13
Literature Cited -------------------------- 14








SIYo








INFLUENCE OF SUMMER PASTURE,
DIETHYLSTILBESTROL, AND SHADE ON
FATTENING CATTLE IN SOUTH FLORIDA

F. M. Peacock, W. G. Kirk, E. M. Hodges,
A. Z. Palmer, and J. W. Carpenter 1


INTRODUCTION

The practice of feeding cattle in small enclosed areas has
been generally accepted as best for animal performance under
fattening conditions, whereas pasture has been utilized for
cheap gains, mostly growth, prior to finishing in the feedlot.
The hot and extremely wet conditions of the flatwoods in south
Florida during the rainy season necessitate feedlot facilities not
commonly needed in most areas. The abundance of summer
pasturage and the lack of necessary feedlot facilities have
brought about wide interest in the utilization of pasture in
finishing slaughter cattle to a U. S. Good or higher grade.
There is the possibility that pastures can be used to ad-
vantage in fattening cattle by the use of stilbestrol (diethylstil-
bestrol) or altering the environment by the use of shade to re-
duce heat stress of animals.
The research reported herein was conducted to determine
the influence of the following factors on finishing steers during
the summer season: 1, pasture versus feedlot; 2, stilbestrol
versus no stilbestrol; 3, shade versus no shade.


REVIEW OF LITERATURE

Results from research on fattening cattle on pasture have
been consistent in that animals responded better to full feed
in drylot than on pasture. Baker et al. (1) stated that despite
greater economy of gain by feeding on pasture, cattle in north
Florida need a period in drylot to finish to the Good and Choice
SAssociate Animal Husbandman, Animal Scientist, and Agronomist,
Range Cattle Experiment Station, Ona; Meat Scientist and Associate Meat
Scientist, Animal Science Department, Agricultural Experiment Station,
Gainesville.
2 Numbers in parentheses refer to Literature Cited.








4 Florida Agricultural Experiment Stations

grades. Results obtained by McCormick et al. (6) and Chapman
et al. (2) indicated drylot fattening to be superior to pasture
fattening as measured by animal performance.
Stilbestrol has been accepted as a means of improving gain
and feed efficiency of cattle being fattened in drylot. Baker (1)
stated that either oral administration of 10 mg per head daily
of stilbestrol in the ration or implantation of 24 to 36 mg at
the beginning of the feedlot period gave an increase in gain,
improvement in feed efficiency, and a boost in economic returns
in north Florida trials. These quantitative results from the use
of stilbestrol have been well established; however, the question
often arises as to the effect it might have on carcass grade.
Data presented by Chapman et al. (2) showed no effect on car-
cass grade of steers implanted with 24 to 36 mg of stilbestrol
and given full feed on pasture. Fontenot et al. (4) reported no
undesirable effects when steers were implanted with 12 mg of
stilbestrol, but increases to 24, 36, and 48 mg per steer lowered
carcass grade.
The need for shade by animals in south Florida has generally
been accepted, but under many conditions neither natural nor
artificial shade is available to the animals. Johnston (5), in
a review of research on the response of beef cattle to environ-
ment, reported that when cattle are exposed to hot, humid con-
ditions which cause a marked rise in body temperature, appe-
tite and efficiency of feed utilization tend to be reduced. Mc-
Daniel and Roark (7) reported that gains by calves on pasture
were significantly higher when shade was provided. McCormick
et al. (6) in Georgia found that carcass grades and gains by
steers being fattened either in feedlot or on pasture were not
affected by shade. Straw and aluminum covered shades were
used.


EXPERIMENTAL PROCEDURES
Pasture Versus Feedlot Plus Stilbestrol
Versus No Stilbestrol
The objective of this study was to compare the performance
of steers fattened with and without 30 mg stilbestrol implant,
on pasture or in feedlot.
Pastures were 5 acres of Argentine bahiagrass, stocked with
two steers per acre. Following completion of each trial in Sep-








Fattening Cattle in South Florida 5

tember, cows grazed the areas until the next spring when they
were removed to allow sufficient growth to take care of the
forage requirements of the steers. The pastures were fertilized
with 300 pounds of a 9-6-6 fertilizer per acre in the spring of
1958, 50 pounds per acre of nitrogen in the fall of 1958, and
500 pounds per acre of 9-6-6 in the fall of 1959. Fertilizer was
not applied in 1960 and 1961, as there was sufficient forage
present for the trials. More than enough forage was present at
all times for the grazing animals.
Feedlot pens were 80 x 100 feet and were enclosed with wire.
No shelters were provided, but the pens were graded to provide
as much drainage as possible during wet season.
This study involved 160 steers over a four-year period with
40 steers in each of the four treatments. The animals used
were grade Brahman approximately 14 months of age at the
beginning of the trials. Once daily all groups of steers were
full fed a concentrate mixture with the steers in feedlot re-
ceiving pangolagrass hay ad libitum. The average daily con-
centrate mixture consumed per steer in each lot is given in
Table 1.
At the completion of each trial steers were trucked a dis-
tance of 76 miles, weighed, and slaughtered at Lykes Brothers
Meat Packing Plant, Tampa, Florida. Carcass weights were
obtained immediately after slaughter, and after the carcasses
had chilled 48 hours, grades were established by a federal

Table I.-Average daily ration of steers with and without stilbestrol fed in feedlot
and on pasture.
Pasture Feedlot
Stilbestrol Control Stilbestrol Control
Lot no. 1 2 3 4
Feed:
Cottonseed hulls, lb. 3.81 3.77 3.84 3.78
Cottonseed meal, 41% protein, lb. 3.72 3.69 3.76 3.70
Corn meal, lb. 1.05 1.04 1.06 1.04
Citrus pulp1, lb. 10.90 10.77 11.01 10.84
Alfalfa pellets, 17% protein, lb. 0.52 0.51 0.52 0.51
Mineral mixture2, lb. 0.22 0.22 0.24 0.24
20.22 20.00 20.43 20.11
Pasture forage ad lib ad lib -
Hay, lb.- -3.56 3.48
1 Lake Wales citrus pulp.
2 Mineral mixture composed of 28 parts steamed bonemeal, 28 parts defluorinated phosphate,
31.21 parts common salt, 3.12 parts red oxide of iron, 0.63 parts copper sulfate, 0.04
parts cobalt chloride or sulfate, 7.00 parts cane molasses, and 2.00 parts cottonseed meal.








6 Florida Agricultural Experiment Stations

grader. Dressing percentages were based on packer weights
and warm carcass weights less 21/) percent for cooler shink-
age. Average daily gains were based on the same final weight.

Pasture Versus Feedlot Plus Shade Versus No Shade
One of the objectives of this study was to determine the in-
fluence of shade on steers being fattened on pasture and in dry-
lot from April to September. Two lots of steers, one provided
with shade and one without, were fed in feedlot, and two on
pasture during each of three years. Steers used in these trials
were approximately 12 months of age with breeding being from
1/ to 3/ Angus with a few Hereford and the remaining blood
being Brahman. The animals fed represented the breeding of
calves currently being produced in south Florida for the feeder
market. This study involved 104 steers over a three-year period
with 26 steers in each of four treatments.
Shades were approximately 14 x 18 x 8 feet covered with 4
mm black polyethylene plastic, allowing an average of 311/2
square feet per animal in the first two years and 25 feet the
last year. Pens were the same as for the previous study, but
pasture for each group consisted of 212 acres of Pensacola
bahiagrass. Pastures received 500 pounds of 10-10-10 fertilizer
per acre prior to grazing in the spring of 1962, 50 pounds of
nitrogen per acre in the spring of 1963, and 300 pounds of
10-10-10 per acre in the fall of 1963. Pastures were not fer-
tilized in 1964. Stocking rate per acre for the first two years
averaged 3.2 steers and for the third year, 4 steers. The pas-
tures furnished adequate forage for the grazing animals.
Once daily all groups of steers were full fed a concentrate
mixture (Table 2) with steers in feedlot receiving pangola-
grass hay ad libitum. Animals were hauled, weighed, slaughter-
ed, and graded, and performance data were recorded in the
same manner as was described previously.
Data collected and included in the analyses were :(a) aver-
age daily gain; (b) carcass grade; (c) dressing percent; (d)
TDN (total digestible nutrients) per 100 pounds gain (Morri-
son, 8) ; (e) TDN per 100 pounds gain for pasture and feedlot
for the seven-year period (supplemental hay and pasture were
not included).
TDN figures are given as relative values, since all lots re-
ceived the same concentrate mixture. Original steer weight








Fattening Cattle in South Florida 7

Table 2.-Average daily ration of steers with and without shade fed in feedlot
and on pasture.
Pasture Feedlot
Shade No Shade Shade No Shade
Lot no. 1 2 3 4
Feed:
Cottonseed meal, 41% protein, lb. 3.04 3.05 3.21 3.30
Ground snapped corn, lb. 2.37 2.37 2.51 2.57
Corn meal, lb. 1.69 1.70 1.78 1.84
Citrus pulp1, lb. 9.64 9.66 10.17 10.47
Mineral mixture", lb. 0.19 0.19 0.20 0.19
16.93 16.97 17.87 18.37
Pasture forage ad lib ad lib -
Hay, lb. 2.44 2.58
1 Given in Table 1.
2 Given in Table 1.

and average daily gains were subjected to covariance analysis.
Original steer weight did not affect average daily gain; there-
fore all data were analyzed by analysis of variance and tested
for significance by using Duncan's "New Multiple Range
Tests" (3).


RESULTS AND DISCUSSION

Pasture Versus Feedlot Plus Stilbestrol
Versus No Stilbestrol

Averages for daily gain, dressing percentage, carcass grade,
and TDN per 100 pounds gain are shown in Table 3. Mean
squares and their statistical significance are given in Table 4.
Daily Gain-Average daily gains among lots were 2.26
pounds for those implanted with stilbestrol on pasture, 2.05 for
pasture control animals, 2.15 for feedlot implanted animals, and
1.92 for feedlot control animals. Stilbestrol accounted for a
highly significant (0.01) increase of 0.21 pound daily gain for
steers on pasture and 0.23 pound for those in feedlot.
Feeding steers on pasture resulted in a significant (0.05)
increase of 0.12 pound daily gain over steers in feedlot, and
stilbestrol accounted for a highly significant increase of 0.23
pound daily over animals not implanted.
Dressing Percentage-Average dressing percentages of
steers among groups were 60.38 for pasture with stilbestrol,









8 Florida Agricultural Experiment Stations

Table 3.-Means for measure of performance and statistical significance' for
pasture versus feedlot plus stilbestrol versus no stilbestrpl.
Pasture Feedlot
Treatment Stilbestrol Control Stilbestrol Control
Lot no. 1 2 3 4
No. animals 40 40 40 40
Av. days on feed 143 143 143 143
Av. initial weight, lb. 603 617 593 603
Av. daily gain, lb. 2.26** 2.05 2.15** 1.92
Av. dressing percent 60.38 61.09 60.83 60.39
Av. carcass grade2 7.28* 7.90 7.63 8.05
TDN/100 pounds gain3, lb. 568 618 586* 662

Treatment Pasture Feedlot Stilbestrol Control
Lot no. 1&2 3&4 1&3 2&4
No. animals 80 80 80 80
Av. days on feed 143 143 143 143
Av. initial weight, lb. 610 598 598 610
Av. daily gain, lb. 2.15* 2.03 2.21** 1.98
Av. dressing percent 60.73 60.61 60.60 60.74
Av. carcass grade2 7.59 7.84 7.45 7.98**
TDN/100 pounds gain3, lb. 593 624 577* 640
"1*-Significant (.05 level of probability); **-significant (.01 level of probability).
2 Grades: 7, Standard; 8, High Standard; 9, Low Good.
SPasture and hay not included.


61.09 for pasture without stilbestrol, 60.83 for feedlot with stil-
bestrol, and 60.39 for steers in feedlot without stilbestrol. No sig-
nificant differences existed among these means. Dressing percent-
age values were so closely related that this factor acted as a
constant, increasing the reliability of the other measurements
pertaining to treatment.
Carcass Grades-Average U.S. carcass grade for all groups
was High Standard (7.71). This average grade was low con-
sidering the time on feed, amount of feed consumed, average
daily gains, dressing percentages, and degree of finish. How-
ever, a significant difference in carcass grade was found be-
tween animals not implanted with stilbestrol on pasture (7.90)
over those implanted (7.28). The same trend existed between
groups in feedlot, but the difference was not significant.
Combining treatments into pasture versus feedlot and stil-
bestrol versus no stilbestrol gave no significant difference be-
tween pasture and feedlot but a highly significant difference
between animals not implanted with stilbestrol (7.98) and those
implanted (7.45).















Table 4.-Mean squares and statistical significance for the various measures of influence of pasture versus drylot, stilbestrol versus
none in fattening cattle.
Average Carcass Dressing TDN/100
Daily Gain Grade Percent Pounds Gain'
Source of Variability d.f. Mean square Mean square Mean square Mean square c

Year (Y) 3 0.1798 33.76** 3.97 4180
Treatment
Drylot vs Pasture (F) 1 0.5796* 2.51 0.63 3783
Stilbestrol vs none (S) 1 1.9648** 11.03** 0.77 16003*
Interaction (FxS) 1 0.0111 0.39 13.18* 649
Interactions
YxF 3 0.1068 0.43 10.10* 767
YxS 3 0.2269 2.02 1.67 2789
YxFxS 3 0.0794 0.34 4.85 826
Error 144 0.1117 1.22 3.11
' Individual sums of squares could not be calculated because each lot was group fed.





t.0








10 Florida Agricultural Experiment Stations

TDN per 100 Pounds Gain-Efficiency of feed utilization for
gain was calculated on a lot basis, as animals were group fed,
which resulted in few degrees of freedom. Average TDN
value per 100 pounds gain for steers on pasture was 568 for
those implanted with stilbestrol and 618 pounds for animals
not implanted. In feedlot, TDN values were 586 pounds for
the stilbestrol implanted steers and 662 pounds for those not
implanted. Stilbestrol accounted for a significant savings of
76 pounds TDN per 100 pounds gain for animals fed in feedlot,
while there was no significant difference for animals fed on
pasture. There was no difference in efficiency of animals fed
on pasture and those in feedlot, but significantly less TDN per
100 pounds gain (63 pounds) was used by animals implanted
with stilbestrol compared with those not implanted.


Pasture Versus Feedlot Plus Shade Versus No Shade

Average measurements are given in Table 5. Mean squares
and their statistical significance are given in Table 6.
Daily Gain-Average daily gains were not significantly dif-
ferent among lots. Combining treatments resulted in no
significant difference between pasture and feedlot, but the dif-
ference of 0.14 pound daily gain in favor of steers having access
to shade was significant. The breeding of steers used in this
study was predominately British.
Dressing Percentage-Average dressing percentages among
treatments were not significantly different. The results showed
that all groups carried essentially the same amount of finish,
and, as in a previous study, dressing percentage values acted
as a constant for the reliability of other measurements relative
to treatments.
Carcass Grade-Average carcass grade of animals in all
treatments was U. S. High Good (11.18), ranging between U. S.
Good and Choice, indicating the quality of steers used in this
study. There were no significant differences among treatments.
TDN per 100 Pounds Gain-There were no significant varia-
tions among means or when treatments were combined, but
inferences drawn from the analysis must take into consideration
the limited degrees of freedom due to group feeding.








Fattening Cattle in South Florida 11

Table 5.-Means for measure of performance and statistical significance' for
pasture versus feedlot plus shade versus no shade.

Pasture Feedlot
Treatment Shade No Shade Shade No Shade
Lot no. 1 2 3 4
No. animals 26 26 26 26
Av. days on feed 163 163 163 163
Av. initial weight, lb. 565 558 566 564
Av. daily gain, lb. 2.02 1.91 2.02 1.88
Av. dressing percent 59.47 59.64 59.24 59.26
Av. carcass grade2 11.04 10.85 11.46 11.38
TDN/100 pounds
gain3, lb. 583 620 616 682

Treatment Pasture Feedlot Shade No Shade
Lot no. 1&2 3&4 1&3 2&4
No. animals 52 52 52 52
Av. days on feed 163 163 163 163
Av. initial weight, lb. 562 565 565 561
Av. daily gain, lb. 1.97 1.95 2.03* 1.89
Av. dressing percent 59.55 59.25 59.36 59.45
Av. carcass grade2 10.94 11.42 11.25 11.12
TDN/100 pounds
gains, lb. 602 649 600 651
S*-Significant (.05 level of probability).
2 Carcass grades: 10, Good; 11, High Good; 12, Low Choice.
3 Pasture and hay not included.


TDN per 100 Pounds Gain from Concentrate for
Pasture and Feedlot over the Seven-Year Period

Examination of all the data over the seven-year period re-
lated to pasture and feedlot showed a definite trend for animals
on pasture to be more efficient in utilization of concentrates
than animals in feedlot. TDN required for 100 pounds gain
from concentrate feed for steers on pasture was 597 and for
those in feedlot 635 pounds. The analysis showed the difference
to be highly significant. These trials were conducted during the
spring and summer season, and even though animals were on
a full feed of concentrate, their consumption of green, palatable
forage could have been responsible for the animals' improved
performance.















Table 6.-Mean squares and statistical significance for the various measures of effect of shade on fattening steers on pasture and in
feedlot.

Average Carcass Dressing TDN/100
Daily Gain Grade Percent Pounds Gain'
Source of Variability d.f. Mean square Mean square Mean square Mean square .

Year (Y) 2 .2335* 16.36** 54.37** 3674
Treatment
Pasture vs feedlot (F) 1 .0030 6.01 2.44 6674
Shade vs none (S) 1 .4163* 0.47 0.20 7854
Interaction (FxS) 1 .0068 0.09 0.14 2915
Interactions 3.
YxF 2 .0351 1.02 7.44 2915
YxS A .0827 0.04 2.92 544
YxFxS 2 .0820 2.47 0.76 578
Error 92 .0637 1.73 2.83
1 Individual sums of squares could not be calculated because each lot was group fed.








Fattening Cattle in South Florida 13

SUMMARY AND CONCLUSIONS
Seven feeding trials comparing the performance of steers
fattened on pasture and in feedlot were conducted. In four of
these trials one-half the steers on each treatment were implant-
ed with 30 mg of stilbestrol each. Shade and no shade treat-
ments were incorporated with the two fattening methods in
trials conducted the last three years.
Stilbestrol increased average daily gains and decreased feed
requirement per unit gain. Carcass grade was reduced, but
most of the variance was between treatments on pasture, as no
significant difference was found between treatments in feedlot.
Dressing percentages did not differ significantly.
Animals having access to shade had a higher daily gain than
those not having shade. There were no significant differences
in feed required for gain, but the data were consistent to the
extent that this factor must be considered. Shade had no effect
on carcass grade or dressing percentage of steers.
Results for the first four feeding comparisons of pasture
with feedlot showed that gains were significantly in favor of
pasture when grade Brahman steers were fed. Pasture and
feedlot did not differ significantly in the last three trials when
steers of predominately British breeding were used, indicating
a possible breed variance. Dressing percentage and carcass
grade variations were not significant.
Steers on pasture required less concentrates for gain than
those in feedlot over the seven-year period, indicating that
grazing did contribute to the steers' performance.








14 Florida Agricultural Experiment Stations


LITERATURE CITED

1. Baker, F. S., Jr. Finishing cattle in north Florida. Fla. Agr. Exp.
Sta. Bul. 675. 1964.
2. Chapman, H. L., Jr., A. Z. Palmer, R. W. Kidder, J. W. Carpenter,
and C. E. Haines. Oral and implanted stilbestrol for beef cattle
fattened on pasture and in drylot. Fla. Agr. Exp. Sta. Bul. 666. 1964.
3. Duncan, D. B. Multiple Range and Multiple F Tests. Biometerics.
Vol. 11, 1955.
4. Fontenot, J. P., R. F. Kelly and J. A. Gaines. The influence of im-
planting graded levels of stilbestrol on grazing beef steers. Va. Agr.
Exp. Sta. Bul. 522. 1961.
5. Johnston, James E. Response to environment. Crossbreeding Beef
Cattle. Univ. of Fla. Press. pp. 61-67. 1963.
6. McCormick, W. C., R. L. Given, and B. L. Southwell. Effects of shade
on rate of growth and fattening beef steers. Ga. Agr. Exp. Sta. Tech.
Bul. N.S. 27. 1963.
7. McDaniel, A. H. and C. B. Roark. Performance and grazing habits
of Hereford and Aberdeen-Angus cows and calves on improved pastures
as related to types of shade. Jour. An. Sci. 15:1:59-63. 1956.
8. Morrison, F. B. Feeds and Feeding. 22nd Ed. Morrison Publ. Co.,
Ithaca, N. Y. 1956.





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