Effects of Diethylstilbestrol, Zeranol and Sex on Live, Blood Metabolite, Carcass and Endocrine Characteristics of Lambs

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Abstract
Forty-eight crossbred lambs, with equal numbers of rams, ewes and wethers, were used to determine the effects of sex and implant treatment on certain blood metabolites and hormones, feed intake and digestibility, live weight gains, carcass traits, endocrine glands and reproductive organs. Ration digestibility was unaffected by implant treatment. Wethers had greater (P<.05) daily gains than ewes while rams consumed more (P<.05) feed per day than wethers per unit of metabolic weight but had intermediate gains. Differences in metabolic activity of diethylstilbestrol (DES) and zeranol were indicated by differential response in blood metabolites, carcass fat deposition, endocrine gland weights and reproductive organ weights. Zeranol resulted in increased ram blood GH levels (80.1%) and a greater decrease in BUN levels in rams (6.6%) and wethers (23.9%) than did DES. However, DES exhibited a greater depressing effect on blood LH levels (33.2%). Zeranol implants also decreased (P<.01) blood insulin and increased Cortisol levels compared to DES-implanted animals. DES implants increased fat thickness (P<.05) and uterine weights (P<.01) compared to non-implanted or zeranol-implanted lambs. The combination of DES and zeranol implants produced no beneficial additive changes, indicating that although these two compounds appear to act differently, their effects are not complimentary. Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science.