Influence of Breed, Sex, Age and Electrical Stimulation on Carcass and Palatability Traits of Three Bovine Muscles1

Sixty bulls and sixty steers representing four breeds (Charolais, Simmental, Hereford and Angus) were assigned randomly, within breeds, to one of three slaughter age end points (12, 15 or 18 mo). The right side from each carcass was electrically stimulated (ES) within 1 h postmortem. The longissimus (LD), semimembranosus (SM), infraspinatus (IS) and biceps femoris (BF) muscles were removed at 7 d postmortem for sensory and shear analysis. Breed had few significant or practical effects on palatability traits. In contrast to previously reported results, bulls and steers at 12 mo of age were generally less tender than those slaughtered at 18 mo. Total cooking losses were less from bulls except in the 18 mo slaughter group. Bulls were rated more tender than steers at 15 mo but the trend was reversed at 18 mo. Electrical stimulation improved ratings for heat ring (two-toning), lean color and lean firmness. These effects were greater in the 12 mo slaughter age group and greater for steers.