Date of this Version
Composition and quality characteristics of 1,121 steer carcasses obtained after mating Hereford and Angus cows to Hereford, Angus, Jersey, South Devon, Limousin, Charolais and Simmental sires were compared at a (1) constant age, (2) constant weight, and (3) constant percentage of fat in the longissimus muscle. Taste panel evaluation was made on a subsample of 496 carcasses. Growth rate of retail product, fat trim and bone differed significantly among sire breed groups. Breed group differences in relative proportions of retail product, fat trim and bone were largest when compared at a constant carcass weight and smallest when compared at equal fat in the longissirnus. There was a positive association between growth rate of breed groups and percentage of retail product or bone. A negative association was observed between growth rate of breed groups and percentage of fat trim. A negative association between growth rate and percentage of fat in the longissimus resulted in breed groups attaining the same percentage of fat in the longissimus at significantly different average carcass weights. Conformation and marbling attributes of quality grade differed significantly among breed groups, but color, texture and firmness of lean and maturity differences were small. Tenderness differences among breed groups were small with all breed groups well above minimum levels of acceptance. Breed group means for taste panel tenderness and marbling were positively associated. Within breed groups, the desirable influence of increased marbling associated with time on feed was essentially counteracted by the undesirable influence of increased age. Breed groups did not differ significantly in flavor or juiciness scores.