Carcass data from 123 pigs slaughtered at either 120 lb., 200 lb. or 260 lb. live-weight have been analysed to study the relative value of four sample joints in predicting tissue composition in the carcass.
Percentage fat, muscle or bone in all joints was highly correlated (P<0·01) with the corresponding percentage of that tissue in the carcass. The highest correlations and correspondingly lowest residual standard errors were found for the loin, rib and composite loin and ham joints.
Significance tests of the a and b constants in regression equations relating percentage fat, bone and muscle in the joint to that in the carcass showed that only with the rib joint was it legitimate to combine the data from each slaughter weight into ‘overall’ equations.
As pooling the data for the combined loin and ham joint had little effect on the magnitude of the residual standard errors, overall equations relating tissue composition of that joint to the whole are also given. The accuracy of prediction, however, was lower than that obtained with the rib joint.
Application of the pooled regression equations relating carcass and rib joint composition to independent data, obtained by identical techniques, gave promising results.