Group Title: NFES mimeo rpt.
Title: Stilbestrol implants for steers on pasture and in feedlot
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Full Citation
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Permanent Link: http://ufdc.ufl.edu/UF00066011/00001
 Material Information
Title: Stilbestrol implants for steers on pasture and in feedlot
Series Title: NFES mimeo rpt.
Physical Description: 6 leaves : ; 28 cm.
Language: English
Creator: Baker, F. S ( Frank Sloan ), 1921-
North Florida Experiment Station
Publisher: North Florida Experiment Station
Place of Publication: Quincy Fla
Publication Date: 1960
 Subjects
Subject: Beef cattle -- Feeding and feeds -- Florida   ( lcsh )
Diethylstilbestrol   ( lcsh )
Hormones in animal nutrition   ( lcsh )
Genre: non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by F.S. Baker, Jr.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00066011
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 69138479

Full Text




NORTH FLORIDA EXPERIMENT STATION
Quincy Florida
January 13, 1960

NFES MIMEO REPORT 60-5


STILBESTROL IMPLANTS FOR STEERS ON PASTURE AND IN FEEDLOT

By F. S. Baker, Jr.


SUMMARY

Two years' results which agree rather closely indicate that steers on
pasture alone should not be implanted with stilbestrol even though implanted
steers may gain slightly more. If cattle are marketed off pasture, side effects
from stilbestrol implants may result in a lower feeder grade and thereby offset
any slight weight advantage from implants. If placed in the feedlot, pasture
implanted cattle apparently.lose their slight weight advantage as compared with
non implanted cattle.

Although carcass grade may be slightly lowered by stilbestrol in some
instances, results of this study indicate that carcass appearance is not affected
as markedly as the on foot appearance of cattle With severe side effects from
stilbestrol.

Whether steers have been previously implanted on pasture or not, it
appears advantageous to implant with stilbestrol when they are placed on a full-
feed of grain in the,feedlot. Best results in this experiment were with steers
not implanted on pasture but implanted when put in the feedlot.
INTRODUCTION

A great number of experiments throughout the United States have shown
the value of stilbestrol, either fed orally or given as an implant, to fattening
cattle. Most of this work has been with cattle on a full-feed of grain in the
feedlot. There have been several pasture studies with stilbestrol; and although
some results have been favorable, results with pasture cattle have not been as
consistent as with cattle on grain rations. Since implants are so easy to
administer, a number of cattlemen have given stilbestrol to cattle on grass
without considering the possibility that the drug may do more harm than good under
some conditions.
PROCEDURE

Yearling cattle, which were previously used in a wintering study, were
divided as equally as possible into two groups when placed on spring pasture
(both yearling and two-year olds were used the second year of the experiment).
Steers in one group were implanted in the ear with 36 mg. diethyl-stilbestrol,
while the other group received no implants. The groups were turned together
on improved grass pasture and grazed throughout the season without supplementary
feed other than minerals.








In the early fall, each group (i.e., pasture implanted or non implanted) were
subdivided into two lots and alternate lots received 36 mg. stilbestrol implants.
The four lots were placed on full-feed in dry lot in separate pens. Following
is a diagram of the various treatments.

Lot Pasture Feedlot

1 36 mg. stilbestrol 36 mg. stilbestrol
implants implants

2 36 mg. stilbestrol none
implants

3 none 36 mg. stilbestrol
implants

4 none none


The cattle were fed until the on-foot appearance indicated most had
attained the U.S. Good slaughter grade. When finished, the steers were picked
up in the early morning before feeding, trucked three miles to Quincy, weighed
and the Quincy weight shrunk 3 percent. The shrunk weights were used as the
final weights calculating gains cardass yields, and sales returns. Carcass
weights were hot weights less 21 percent. Carcass grades were composites of
grades-by U.S. Graders and Experiment Station and packing house personnel.
Carcasses were ribbed and degree of marbling was considered in determining grade.
Sale prices were based on actual carcass values.

RESULTS AND DISCUSSION

Two year results are given in Table 1. As results for the two years
agreed very closely, only the average is shown.

Steers implanted at the beginning of the pasture season gained an average
of 18 pounds per head more in 166 days than those not implanted. With the same
valuation per cwt. at the beginning of the summer and the same pasture cost for
the two groups of cattle, the added weight of the pasture implanted cattle resulted
in their costing approximately $0.50 cwt. less than the control steers going into
the feedlot. This amounted to a difference of about $3.75 per head. However,
feeder buyers estimated that the pasture implanted steers would have been worth
about $2.00 per cwt. or $15.00 per head less than the non-implanted cattle had
they been sold at the end of the pasture season and not placed in the feedlot.
This difference in value was due to the pronounced side effects resulting from
implantation. Apparently there is not enough fat deposition in pasture cattle in
this area to partially mask the changes in appearance resulting from stilbestrol
implantation, while in feedlot cattle the rather fast gains and resulting fat
deposition cover-up to a certain extent these changes in appearance. This suggests
that stilbestrol should not be usedwith. cattle on pasture or other rations unless
rapid gains (around 2.00 lbs. daily) are expected, especially if the cattle are to
be marketed directly off pasture and not put in the feedlot.


-2-









Table i- Stilbestrol Implants for Steers on Pasture and in Feedlot
(Two year average results).


I. PSTURE PHASE


36 mg. Implant


* No Implant


Number days
Average initial weight
Average final tight
Average gain
Average daily gain
Value per cwt. start season
Cost per cwt. end pasture
season (into feedlot)


II FEEDLOT PHASE


Number days
Average initial weight
Average final weight
Average gain
Average daily gain

Average Daily Ration


Lot 1
Implant

104
754
1050
296
2.85


Lot 2
No implant


105
759
1013
254
2.37


Lot 3
* Implant

104
766
1077
312
2.96


Lot 4
No Implant


105
743
988
245
2.34


. Concentrates
Hay


Feed per 100 Pounds Gain


Concentrates
Hay
Cost


Slaughter and Financial Data

Carcass weight
Carcass yield (percent)
Ave. carcass grade

"*Market value cwt. on foot
Net return above costs


912
169
$ 20.49


615
58.59
low
good
$ 24.55
46.16


1057
206
$ 23.88


599
59.65
average
good
$ 25.00
42.58


895
151
$ 20.00



648
60.10
average
good
$ 25.62
57.45


* One steer with "hardware disease" removed from trial.
B- Eased on actual sale price carcasses.


-3-


166
605
757
152
0.91
$ 22.50


166
620
753
134
0.79
$ 22.50


20.07


20.54


25.95
4.84


24.50
4.65


26.22
4.44


24.89
3.38


1073
146
$ 23.61


587
59.33
average
good
$ 25.11
38.55








When placed in the feedlot on a full-feed of grain, steers implanted with
36 mg. of stilbestrol made faster and more economical gains regardless of whether
or not they were previously implanted on pasture (Tables 1 and 3). Steers not
implanted on pasture but implanted going into the feedlot (Lot 3) made fastest,
most economical gains; yielded heaviest carcasses; and had highest net returns.
Steers implanted both on pasture and in the feedlot (Lot 1) graded slightly lower,
yielded slightly less, and were worth slightly less per cwt. when slaughtered than
the other groups. It is also interesting to note that steers not implanted on
pasture (Lots 3 and 4, Table 1) were worth as much per head when marketed at the
end of the feedlot period and had as high a net return as the steers implanted on
pasture (Table 2).

Based on these results, it is recommended that stilbestrol not be implanted
in steers on pasture without supplementary feed, but it is recommended that
stilbestrol implants be given (or stilbestrol be fed) when steers are placed on a
full-feed of grain. It is further suggested that stilbestrol hot be used with
steers on rations that will hot produce gains of about 2.00 pounds per head daily
or more.









Table 2: Stilbestrol Implants for Steers on Pasture and in Feedlot
(Two year average results).


I. PASTURE PHASE


* Implant Pasture


* No Ijnplant Pasture


See Table 1


II. FEEDLOT PHASE


Number days
Average initial weight
Average final weight
Average gain
Average daily gain

Average Daily Ration


Concentrates
Hay


Feed per 100 Pounds Gain

Concentrates
Hay
Cost

Slaughter and Financial Data

Carcass weight
Carcass yield (percent)
Ave. carcass grade

Market value cwt. on foot
Net return above coats


(combined groups shown Table 1).


105
757
1032
276
2.62


25.25
4.74


970
183
$ 21.85


607
58.84
average
good
$ 24.76
44.42


* Half implanted when placed in feedlot.
** Based on actual price carcasses.


105
753
1029
276
2*62


25.47
3.87


977
154
$ 21.66


614
59.71
average
good
$ 25.36
47.38









Table 3: Stilbestrol Implants for Steers on Pasture and
(Two year average results).
1^


in Feedlot


FEEDLOT PHASE


* Implant Feedlot


* No Implant Feedlot


Number days
Average initial weight
Average firal weight
Average gain
Average daily gain

Average Daily Ration


Concentrates
Hay


Feed per 100 Pounds Gain

Concentrates
Hay
Cost

Slaughter and Financial Data

Carcass weight
Carcass yield (percent)
Ave. carcass grade

SMarket value per cwt. on foot
Net return above costs


Half previously implanted on pasture.
W* Based on actual sale price carcasses.


104
759
1062
303
2.89


105
751
1001
250
2.36


26.03
4.65


24.70
4.02


904
161
$ 20.27


630
59.32
average
good
$ 25.06
51.22


1065
175
$ 23.71


593
59.24
average
good
$ 25.05
40.87


-6-




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