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Wholesale cut composition of 642 carcasses obtained from steers that were from matings of hETEFORD AND Angus cows to Hereford, Angus, Tarentaise, Pinzgauer, Brahman and Sahiwal sires were analyzed after adjusting carcasses to a common weight or a common fat trim percentrage. At a common carcass weight, the wholesale cut percentages and the composition of cuts differed (P<.01) among sire breed groups. At a common fat trim percentage, differences in the distributions of total retail product, fat trim or bone among cuts were small yet statistically significant among sire breeds. Compared with the Bos taurus breed groups, the two Bos indicus sire breed groups had slightly lower wholesale chuck percentages and similar percentages of total retail product in the chuck even though the modest [...]

Wholesale cut composition of 642 carcasses obtained from steers that were from matings of hETEFORD AND Angus cows to Hereford, Angus, Tarentaise, Pinzgauer, Brahman and Sahiwal sires were analyzed after adjusting carcasses to a common weight or a common fat trim percentrage. At a common carcass weight, the wholesale cut percentages and the composition of cuts differed (P<.01) among sire breed groups. At a common fat trim percentage, differences in the distributions of total retail product, fat trim or bone among cuts were small yet statistically significant among sire breeds. Compared with the Bos taurus breed groups, the two Bos indicus sire breed groups had slightly lower wholesale chuck percentages and similar percentages of total retail product in the chuck even though the modest hump in the Bos indicus group was included in the chuck. Differences in distribution were not large enough to give any sire breed grou^p a distinct advantage in percentage of
retail product contributed by the more preferred cuts. Greatest variation among sire breeds was in fat distribution, particularly kidney and pelvic fat. Regression coefficients of retail product, fat trim and bone side weight were calculated from covariance within and between slaughter dates of sire breed groups. The coefficients for within and beween slaughter group regressions, when averaged over all sire breed groups, were, respectively : retail product, -8.8 and -22.6%/100 kg; fat trim, 11.0 and 27.2%/100 kg and bone, -2.2 and - 4.7%/100 kg side weight. Our interpretation of the differences between sets of regression coefficients was that increases in weight associated with continued feed intake resulted in greater increases in fat to lean ratio than from increased weight associated with genetic growth potential. These results, which confirm those reported earlier from different populations, show that the opportunity for increasing the proportion of lean
in the more preferred cuts is extremely limited because of the small amount of variation in muscle distribution. Most of the variation in wholesale cut percentages and composition of cuts was associated with differences in total lean and fat yield among sire breed groups. ("éRésumé des auteurs").