Low Level Diethylstilbestrol Implantation for Lambs Grazing Alfalfa

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Abstract
Factorial experiments were conducted using a total of 354 western feeder lambs to obtain information relative to stilbestrol implants for lambs grazing irrigated alfalfa. Wethers and ewes of whiteface or blackface phenotype showed varying response to the implanted hormone. The whiteface lambs were more consistent in response, with increased daily gain at all levels of implants and with wethers gaining more than ewes. Blackface wethers failed to respond to a 3-mg. implant in one trial, but showed a response in a later trial to 3 mg. but not to 6 or 12 mg. Slightly increased gains of implanted blackface ewes were not generally significant. Spaying had no conclusive effect on the performance of the ewes. Control lambs were fatter than implanted sheep. The trend was for lower yields and lighter fat corrected carcass weights especially for lambs implanted with 6 or 12 mg., but significant interactions were present between sex x breed and breed x hormone level that make a definite statement in this regard untenable. Energy per pound of gain was significantly lower (av. 230 kcal./lb. of gain with 95% confidence limit of ±72 kcal.) for stilbestrol implanted lambs. This, with other data, leads to the conclusion that improved feed efficiencies usually demonstrated for stilbestrol treated lambs are probably not real if placed on a caloric basis. Pasture intake averaged 3.6 Ib./head daily as measured by before and after clipping procedure. The NEM±P of the consumed forage was 44 megcal./100 lb. as determined by the specific gravity comparative slaughter technique. Copyright © 1964. American Society of Animal Science . Copyright 1964 by American Society of Animal Science

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