| ecords for 488 crossbred steer calves from the fifth generation of a long term crossbreeding study were used to calculate heritabilities, correlations and breed effects for growth and carcass traits. Traits studied were birth weight; weaning weight; gain on feed; final live weight; weight per day of age; hot carcass weight; longissimus muscle area; marbling; kidney, pelvic and heart fat; slaughter age; fat thickness; and color of lean. Data were analyzed using multiple trait DFREML procedures with a full animal model. At weaning, 60% of the steers were assigned to an accelerated management system and the remainder to a conventional system. Low heritabilities were found for maternal birth and weaning weight, direct birth weight, and gain on feed. Weight per day of age and kidney, pelvic, and heart fat were highly heritable. Longissimus muscle area, marbling, and slaughter age were moderately heritable. Correlations among growth traits were all positive and moderate to high in magnitude. Genetic correlations between carcass traits ranged from... |
