THE COMPARATIVE VALUE OF DIETHYLSTILBESTROL, DIENESTROL DIACETATE AND SMILAGENIN FOR FATTENING BEEF STEERS 1/
Research Progress Report 83
September, 1963 Final
Martin Stob, T. W. Perry, M. T. Mohler and W. M. Beeson, Animal Sciences Department
Summary
The data summarizing the effects of oral hormonal treatment on growth and feed efficiency are presented in Table 1.
Total gain was increased 11 percent by 10 mg. stilbestrol (lot 2) and 7 percent by 15 mg. dienestrol diacetate (lot 4) administration. These differences were highly significant (P 0.01). Both treatments improved feed efficiency by 6 percent compared to lot 1. Gost of gain was reduced by each treatment.
The 10 mg. level of dienestrol diacetate and the 10 mg. and 20 mg. levels of Smilagenin did not improve total gain or feed efficiency.
All hormone treatments tended to reduce carcass grade but had little effect on dressing percent (Table 2).
Use of Hormones
Increased rate of gain and improved feed efficiency resulting from the treatment of cattle with hormones has been of benefit to thousands of cattle feeders. At times, the use of hormones has been the determining factor between profit or loss of a cattle feeding operation for a given year. The hormones which are the most effective growth stimulators are the estrogens or
female sex hormones. Compounds like hexestrol, dienestrol, estradiol and possibly some estrogens found in plants all increase rate of gain in cattle, but the most widely used estrogen in cattle feeding operations is diethyl stilbestrol (stilbestrol). New compounds which might have growth promoting activity must be compared to the results obtained with the use of stilbestrol.
The use of stilbestrol as a growth promoter in cattle feeding is not without its problems. One problem is the so-called "side effects, "such as low loins, high tail heads and mammary development. We have mentioned at previous Cattle Feeders’Days that these "side effects" are true estrogenic effects and that to date it has been impossible to produce growth and (feed efficiency improvement without getting some estrogenic effects. Another problem associated with stilbestrol feeding are the hormone residues which may be present in the liver if cattle are slaughtered too soon after the last stilbestrol feeding. For this reason, 48 hours must elapse between the last feeding of stilbestrol and the slaughter of the cattle. Other problems might arise from accidental use of stilbestrol feeds for classes of livestock for which it is not intended.
The purpose of the present experiment was to compare the growth promoting effects of dienestrol diacetate and Smilagenin with those produced by stilbestrol. Both
1/ The American Scientific Laboratory, Inc. furnished the dienestrol diacetate, and Charles Pfizer and Co. furnished the Smilagenin used in this experiment.
PURDUE UNIVERSITY • Agricultural Experiment Station • Lafayette, Indiana