Growth Rate, Feed Utilization and Body Composition of Young Bulls and Steers

Abstract

Three experiments were conducted to determine (1) the relative growth rate, feed utilization and body composition of young bulls and steers, and (2) the effect of stilbestrol implantation on characteristics of bulls and steers. During two of the experiments part of the calves were fed in individual pens. The others were fed in groups. Bulls and steers were similar in preweaning growth rate. Bulls grew more rapidly in the feedlot than steers, were more efficient in feed conversion and produced leaner carcasses. Steers appeared to have a consistent advantage in carcass grade. The effect of stilbestrol implantation on characteristics of bulls and steers was not the same. Stilbestrol implantation (24 mg.) caused a significant increase in the growth rate of steers and a reduction in the amount of fat in the carcass. Bulls implanted with 60 mg. stilbestrol tended to gain more rapidly and were somewhat fatter than controls, but the effect of the hormone on characteristics of bulls was less pronounced than with steers. There was some indication in one experiment of an increase in the carcass grade of bulls which had received stilbestrol. Differences in daily gain and feed efficiency of bulls and stilbestrol-implanted steers were not significant. Differences in growth rate due to method of feeding were generally nonsignificant. Copyright © 1966. American Society of Animal Science . Copyright 1966 by American Society of Animal Science