Document Type



Although the usefulness of orally administered diethylstilbestrol (stilbestrol) in increasing weight gains and feed efficiency of fattening cattle has been established, little is known concerning the mechanism by which it exerts its beneficial effect. Two possible modes of action may exist. First, the stilbestrol may have some effect on the rumen microorganisms which might cause an increased digestion of feed in the rumen. Brooks et al. (1954) have shown that stilbestrol increased the digestibility of cellulose in the artificial rumen. They also obtained increased cellulose and protein digestion in sheep when stilbestrol was fed. However the levels fed the sheep were considerably above the mg. per lamb per day reported to be effective with lambs (Hale et al. 1955). Sykes et al. (1956) reported an increase in crude fiber digestibility and a decrease in protein digestibility with lactating cows when stilbestrol was fed. Digestibility of the dry matter of the ration tended to be improved but the differences were not statistically significant. Erwin et al. (1956) reported stilbestroI had no effect on digestibility of dry matter, crude fiber, crude protein or ether extract with steers. Secondly, the orally fed stilbestrol may exert some action on the metabolism of the animal's tissue which is thought to occur when the stilbestrol is implanted (Clegg and Cole, 19 54). It has been shown that implanted stilbestrol increased nitrogen retention but had no effect on ration digestibility (Jordan 1953: Whitehair et al. 1953). Bell et al. (1955) found that orally fed stilbestrol increased nitrogen retention in lambs. Presumably this action is brought about by the absorbed stilbestrol acting similar to that on the implanted stilbestrol. The objectives of this report were to study the effects of different levels of stilbestrol upon the digestibility of dry matter and crude protein and on nitrogen retention with wether lambs.

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Journal Title

Proceedings of the Iowa Academy of Science





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©1957 Iowa Academy of Science, Inc.



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