TENDERNESS VARIATION AMONG LOIN STEAKS FROM A AND C MATURITY CARCASSES OF HEIFERS SIMILAR IN CHRONOLOGICAL AGE

Fifty-two Angus x Gelbvieh rotationally crossed virgin, ovariectomized , or single-calf heifers were slaughtered after 100 d on a high-concen trate diet. Heifers from each treatment were approximately 31, 33, or 35 mo of age, and they produced 31 A, 5 B, and 16 C maturity carcasses . Because of the small number, B maturity carcasses were not included in this study. Number of A maturity carcasses decreased as age increas ed; No differences (P > .05) in slaughter weight, total weight gain, d ressing percentage, longissimus muscle area, or kidney fat percentage existed between carcass maturity groups, but C maturity heifers had 3. 56 mm more fat (P < .91) over the longissimus muscle than A maturity h eifers. Marbling scores of slight(79) and small(0) for A and C maturit y carcasses, respectively, did not differ (P > .05). The A and C matur ity heifers had similar amounts of collagen and hydroxylysyl-pyridiniu m crosslinks in metacarpal bone cortex and in longissimus muscle. Neit her means for panel tenderness nor Warner-Bratzler shear values differ ed (P > .05) between maturity groups. Coefficients of variation for te nderness were slightly higher in steaks; from C maturity carcasses, bu t CV for shear values between A and C maturity groups were similar. Be cause inconsistent meat tenderness is a recognized problem in the beef industry, more research on tenderness variability within maturity and marbling groups is needed. This information, in addition to pooled SE M and differences between means, should aid in finding ways to reduce beef tenderness variability.