Effect of Prenatal Androgeimization on Growth Performance and Carcass Characteristics of Steers and Heifers

Abstract
Two experiments were conducted in which pregnant crossbred cows were randomly assigned to a control group or implanted with testosterone propionate/silastic implants between d 110 and 140 of gestation in Exp. 1 and between d 80 and 110 of gestation in Exp. 2. Androgenized heifers (TH) and treated steers (TS), born to implanted dams, possessed similar birth weights compared with control heifers (CH) and steers (CS), respectively, in both experiments. In Exp. 1, yield grades were lower (P < .05) for TH than for CH. In Exp. 2, TH possessed 9.4% greater (P < .07) 205-d adjusted weaning weights and 9.8% heavier (P < .05) adjusted yearling weights than CH. In Exp. 2, daily gain was 19.5% faster (P < .05) and feed intake was 13.6% greater (P < .05) for TH than for CH. In Exp. 2, TH possessed less (P < .05) s.c. fat, greater (P < .10) carcass weight gains and lower (P < .05) yield grades than CH. Liver weight per unit of carcass weight was greater (P < .07) for TH than for CH in Exp. 2. Androgenized heifers had lower (P < .07) lipid content in the 9-10-11th rib section than did CH. Calving intervals were similar for implanted and nonimplanted cows in both experiments. Results from these two trials suggest that efficiency of heifers for producing carcass beef can be improved by prenatal testosterone exposure. Copyright © 1988. American Society of Animal Science . Copyright 1988 by American Society of Animal Science

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