Effects of Creep Feeding and Sex on the Rate and Composition of Growth of Crossbred Calves

Fifty-three fall-dropped crossbred calves were randomly assigned within sire and sex to either a creep-fed or a noncreep-fed group when they were put on pasture with their dams.The calves remained on pasture until the end of the pasture season when they were put on full feed in the feedlot. The heifers were slaughtered at approximately 431 kg. and the steers at 454 kg.liveweight. Creep feeding did not influence (P<.05) any of the measurements of carcass composition and quality.The rate of gain on pasture and weight per day of age at slaughter were higher for creep-fed cattle.The CF cattle also were slightly more efficient in feed utilization than the noncreep-fed cattle. On a per day of age basis, the shrunk live slaughter weight, hot carcass weight and weight of trimmed round and loin were greater for creep-fed cattle fed to a similar weight than for noncreep-fed cattle. The steers made faster liveweight gains and had less fat, as measured by a single fat thickness,specific gravity of the 9–10–11th rib section and percent trimmed round, than the heifers. Therefore, a greater planned differential in slaughter weights than was present in this study is suggested in order to obtain equal carcass cutabilities for the two sexes. Although the steers had higher percentages of trimmed round, the percentages of trimmed loin did not differ between sexes.The steers had higher carcass conformation scores and a more desirable color of fat than the heifers.