Evaluation of sources of variation for the weight of 5 pork primal and subprimal cut weights

The objective of this trial was to evaluate sources and magnitude of variation for pork cut weights. The weights of 5 primal and subprimal cuts were evaluated from 1,688 barrows and gilts of 3 sire and 2 dam lines at target market BW of 113, 127, or 141 kg. The cut-weight data were fitted to an allometric function of carcass weight (cut weight, kg = A · CWB), where A is a scalar parameter, B is the allometric coefficient, and CW = carcass weight. The equation was linearized as log10(cut weight, kg) = log10A + Blog10(CW) and included the fixed effects of sire line, dam line, and sex and their interactions with log10CW. The predicted values of the cut weights were included in a model including the random effects of replicate, room within replicate, and pig and fixed effect of side. Left-side weights were greater (P < 0.01) than right-side weights for bone-in loin, rough-cut belly, and trimmed belly weight. The allometric functions of CW accounted for 47 (rough-cut belly) to 68% (bone-in loin) of the total variance in the cut weights. The random effect of pig accounted for 7.9, 2.4, 22.3, 11.6, and 14.9% of the variance for bone-in ham, bone-in loin, boneless loin, rough-cut belly, and trimmed belly weight, respectively. The within-pig side-to-side variation accounted for 23.9, 27.1, 26.7, 15.2, and 17.2% of the total variance in the cut weights. Approximately 30 to 49% of the total variation in cut weights remained when pigs of the same population and CW were processed.