Some Simple Cut Indices for Predicting Carcass Traits of Swine. I. Cut-Out and Loin Lean Area

Results indicate that simple cut indices involving a minimum number of weights and adapted to large scale useage may be utilized in evaluating swine carcasses. The loin index, which is the percentage of trimmed loin in relation to rough loin, appears to be more promising than the trimmed loin-fatback ratio or the percentage trimmed loin on either the live or carcass basis. A comparison of the loin index and backfat thickness as measures of lean cuts (carcass basis) justifies the conclusion that loin index more accurately reflects percentage lean cuts. Although percentage skinned ham (both live and carcass bases) and percentage New York shoulder (both bases) indicate cut-out nearly as well as the various loin indices, all loin indices were superior as indicators of loin lean area. On the other hand, the percentage trimmed belly was a poor indicator of all cut-outs and loin lean area. Consideration of the pigs by groups showed the hormone treated-delayed castrated-limited fed group generally had higher correlation coefficients between the cut indexes and all carcass cut-outs and loin lean area than was true for the barrows or gilts. The greater variability of the treated group was apparently responsible for the higher relationships. Data from pigs on treatments which are distinctly different than those commonly used by commercial swine producers should not be used as a basis for measuring the usefulness of various evaluation procedures.