Date of this Version
Carcasses of 786 steers derived from crosses of Hereford or Angus cows bred to Hereford, Angus, Charolais, Limousin, Simmental, South Devon, and Jersey sires were fabricated into closely trimmed, semi-boneless retail cuts to study relationships among independent variables in the USDA yield grade equation in breed groups that differ in growth and fattening characteristics.
fattening characteristics. Simple correlations indicate carcass weight was a good predictor of cutability within a breed group but a poor indicator over all breed groups. Rib eye area had the lowest predictive value of the four variables studied. Rib eye area may be more useful in populations of similar weight than in those varying widely in weight. Fat thickness at the 12th rib was the most useful predictor of cutability and is about equally useful within or over all breed groups. Percentage of kidney and pelvic fat, though lower in predictive value than 12th rib fat thickness, was useful within or over breed groups. Partial regression coefficients computed within each breed group were relatively similar though there were significant differences in intercept values for the different breed groups. Use of a single prediction equation for all breed groups would rank animals well within a breed group.