Effect of Stilbestrol on Suckling and Fattening Lambs

Abstract

Subcutaneous implantation of 12 mg. stilbestrol in the jaw of suckling lambs failed to increase rate of gain in suckling lambs 2½–3 months of age. A slight but statistically insignificant increase resulted when suckling lambs 3½–4 months of age were treated. General type was not affected by treatment but an increase in the size of the mammary glands and formation of normal appearing milk was evident in the treated lambs. Testes growth was arrested but approximately 4–5 months post-treatment the testes appeared normal. Treatment of fattening lambs with 12 mg. stilbestrol increased rate of gain and feed efficiency significantly. Carcass grade was lowered considerably and carcass yield slightly. Treated lambs tended to shrink more following slaughter than control lambs. Total cooking losses including water vapor and drippings were of about the same magnitude in both groups. There was no difference in digestibility of the feed nutrients by the lambs in the two groups. Milligrams of nitrogen per milliliter of urine were approximately the same for both groups. However the treated lambs excreted considerably less urine and consequently excreted less nitrogen. Nitrogen retention was approximately 30 percent greater in the treated lambs. A severe outbreak of prolapse of the rectum, and uterus resulting in urinary blockage and death occurred in a band of 9,000 lambs treated with 12 mg. of stilbestrol.