Changes in Carcass Weight and Characteristics with Increasing Weight of Large and Small Cattle

The effects of live weight on carcass weight and of carcass weight on carcass characteristics were quantified using 145 large and small cattle represented by Holstein and small-framed Angus steers. Cattle were fed to one of five final weights ranging from 363 to 544 kg for Angus and from 454 to 612 kg for Holstein. Hot carcass weight increased (P<.005) .74 kg for each kg increase in live weight. Marbling score, quality grade and rib eye area increased (P<.005) .028 units, .027 units and .1 cm2, respectively, for each kg increase in chilled carcass weight. Angus carcasses had greater fat thickness and higher estimated percentage kidney, pelvic and heart fat (KPHF) except at heavier weights where percentage KPHF was greater for Holstein carcasses. Fat thickness increased .005 cm/kg faster (P<.005) and percentage KPHF increased .005 percentage units/kg slower (P<.025) for Angus carcasses. The only diet effect on carcass characteristics was a one-sixth quality grade difference (P<.05) in favor of the grain diet. Carcasses from all diets, breeds and housing types exhibited the same .012-unit change (P<.005) in numerical yield grade for each kg increase in chilled carcass weight. These results, combined with analyses of data from the literature, can be used to predict change in carcass weight with increasing live weight and changes in carcass characteristics with increasing carcass weight.