Research Progress Report 252 April, 1966
Effects of Feeding Regime on Steer Body Composition
R. R. Garrigus, H. R. Johnson, and M. D. Judge
Department of Animal Sciences

Summary
Cattle fed corn silage during the early feeding period had more carcass weight, greater dressing percentages, more fat cover, and less reticulo-rumen weight than those fed hay for the same period, regardless of slaughter weight. Carcasses from cattle fed hay during the early period had a higher percentage of edible portion in both light and heavy slaughter groups with less weight in edible portion in the light groups but more in the heavy groups. All of these comparisons were significant at the 1% level.

Suppressed muscle development in carcasses from cattle fed hay during the early period was followed by compensatory muscle growth during the intermediate and final periods. Feeding concentrate versus silage beginning at 750 pounds, following silage, had little effect until these all received concentrate at the 900 pounds weight. Those that previously received concentrate continued their decline in edible portion percentage while those previously receiving silage remained at about the same percentage.
Cattle receiving silage through 750 pounds had significantly (1% level) more rib eye area than those fed hay. In the heavier
slaughter groups, steers fed silage in the early period had significantly (5% level) higher marbling scores than those fed hay.

Objectives and Experimental Procedure
Cattle feeders usually feed weanling calves in one of two ways, either grow them through the winter on a low-energy roughage ration or push them with higher energy feeds. Maximum muscle development has been shown to occur during the first 200-250 pounds post-weaning gain. This could be the period that determines whether or not a steer produces a meaty carcass and is probably the period during which most efficient gains occur.

This experiment was designed to study the effect of age and early rate of gain on carcass traits and to demonstrate the effects of corn silage as compared to a conventional post-weaning, low-energy wintering ration on the carcass at various stages of development.

One hundred and four, non-creep fed, half-brother Angus steers averaging approximately 454 pounds were used. They were

PURDUE UNIVERSITY • Agricultural Experiment Station • Lafayette, Indiana