Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 17, 1995
Publication Date: N/A
Interpretive Summary: It has long been recognized that the loin muscle (Ribeye and Top loin steaks) from Bos indicus breeds of cattle (breeds, such as Brahman, that evolved in tropical climates) is tougher on average than the loin muscle from Bos taurus breeds of cattle (breeds, such as Angus and Charolais, that evolved in temperate climates). However, the effect of genetics on the tenderness of other muscles of the beef carcass has not been explored. This experiment demonstrated that most cuts of meat were tougher for Bos indicus carcasses as compared to Bos taurus carcasses. However, genetic effects on tenderness were greatest for the loin muscle. Tenderness of the most tender cuts of meat, Tenderloin and Top blade steaks, was not affected by genetics.
The present experiments were conducted to determine 1) the relationship between shear force and overall tenderness of ten major beef muscles, 2) the effect of Bos indicus inheritance on the tenderness of various beef muscles, 3) if differences in tenderness between genotype are affected by method of cookery, and 4) the relationship between tenderness of the longissimus muscle and tenderness of other muscles. To meet the first objective, shear force and trained sensory panel overall tenderness were determined for psoas major (PM), infraspinatus (IS), triceps brachii (TB), longissimus (LD), semitendinosus (ST), gluteus medius (GM), supraspinatus (SS), biceps femoris (BF), semimembranosus (SM), and quadriceps femoris (QF) steaks from grain-fed steer carcasses (n = 16). Shear force did not accurately reflect differences among muscles in overall tenderness, however, accurate (r**2 = .81) equations were developed to transform shear values to overall tenderness ratings. To accomplish the remaining objectives, muscles were removed from grain-fed Bos taurus X Bos taurus (n = 31) and Bos indicus X Bos taurus (n = 18) steer carcasses and aged until 14 d postmortem. Tenderness of LD, TB, SS, BF, and QF steaks and QF, BF, TB, and LD roasts was lower (P < .05) for progeny of Bos indicus sires compared to progeny of Bos taurus sires. Tenderness differences among genotypes were reduced slightly by roasting. Tenderness of LD was not highly related to tenderness of other muscles. Thus, systems that accurately predict the tenderness of LD of a carcass will likely do little to predict the tenderness of other muscles.