Heritabilities and phenotypic and genetic correlations for bovine postrigor calpastatin activity, intramuscular fat content, Warner-Bratzler shear force, retail product yield, and growth rate

To estimate the heritability (h2) of postrigor calpastatin activity (CA), 555 steers were reared and processed conventionally. Breed-types in- cluded purebreds (Angus (AI, Braunvieh (Bl, Charolais (C), Gelbvieh (GI, Hereford (HI, Limousin (L), Pinzgauer (PI, Red Poll (RPI, and Simmental (SI), composite populations (MARC I (1/4 C, 1/4 B, 1/4 L, 1/ 8 H, 1/8 A), MARC I1 (1/4 S, 114 G, 1/4 H, 114 AI, and MARC I11 (1/4 RP, 1/4 H, 1/4 P, 1/4 AI), and F1 crosses (H, A, C, G, P, Shorthorn, Galloway, Longhorn, Nellore, Piedmontese, or Salers x H or A). Steers were serially slaughtered on an age-constant (across breed groups) basis. Heritability estimates for CA, i.m. fat content (IMF), Warner-Bratzler shear ( W B S) force,