Effect of feeding regimen, breed and sex condition on carcass composition and feed efficiency.

Eighty bulls and eighty steers representing four breed types (7/8 Angus. 7/8 Simmental, 7/8 Simmental × 7/8 Angus and 7/8 Simmental × 7/8 Hereford) were randomly assigned to two diets by sex class and breed type. Exotic breeds produced heavier, leaner, more muscular carcasses, with lower USDA quality grades and darker colored, coarser textured lean. Angus 9-10-11th rib composition showed that Angus tended to have less lean, more bone and the most fat when compared to the Simmental and Simmental crosses. Feeding the deferred diet resulted in carcasses with (P < 0·05) less fat, lower USDA quality grade, smaller ribeyes, more sensory panel detectable connective tissue, higher cooking losses and higher Instron shear values. Sex class caused differences (P < 0·05) in feed efficiency, carcass traits and sensory properties.