FEEDLOT AND CARCASS PERFORMANCE OF YOUNG BULLS REPRESENTING SEVERAL BREEDS AND BREED CROSSES

Abstract

A population of 174 hybrid bulls was used to evaluate pre- and postweaning growth and carcass characteristics of crosses involving Angus, Hereford, and Holstein dams and Angus, Hereford, Brown Swiss, Charolais, and Shorthorn sires. Progeny of Holstein dams excelled (P < 0.01) for pre- and postweaning growth traits. Breed of sire differences were generally nonsignificant except for growth rate in the feedlot. Dressing percentage was not influenced by breed of dam or sire. Hide weight was least for progeny of Holstein dams and greatest for progeny of Hereford dams and sires (P < 0.01). Holstein and Brown Swiss crosses had a higher proportion of bone (P < 0.01), a greater proportion of chuck and round, and a lower proportion of rib and sirloin than crosses from the British breeds. Area of rib eye was influenced by breed of dam but not breed of sire. British breed crosses had the greatest and Holstein, Brown Swiss, and Charolais crosses the least rib fat (P < 0.01). Total deboned–defatted lean yield of the carcass was least for the British breed crosses. Breed crosses did not differ in ether extract values from the longissimus dorsi but British breed crosses showed the greatest degree of marbling. No breed of sire or breed of dam differences were detected in tenderness of the longissimus dorsi, either by Warner-Bratzler or taste-panel evaluation, but significant breed of sire–breed of dam interactions were evident for these traits. Progeny of Hereford dams were more efficient (P < 0.01) than progeny of Holstein dams in converting feed to liveweight gain. This tended to negate the Holstein-cross advantage in growth rate and lean content, and there were no breed of dam differences in energy requirements per unit of lean produced. For the breed of sire comparisons, calves from the British breeds required the greatest energy intake per unit of lean product (P < 0.05).