Effect of hot carcass weight on loin, ham, and belly quality from pigs sourced from a commercial processing facility

The objective was to determine the predictive abilities of HCW for loin, ham, and belly quality of 7,684 pigs with carcass weights ranging from 53.2 to 129.6 kg. Carcass composition, subjective loin quality, and ham face color were targeted on all carcasses, whereas in-plant instrumental loin color and belly quality were assessed on 52.0 and 47.5% of carcasses, respectively. Loin chop slice shear force (SSF), cured ham quality, and adipose iodine value (IV) were evaluated on at least 10% of the population. The slope of regression lines and coefficients of determination between HCW and quality traits were computed using PROC REG of SAS and considered significant at P ≤ 0.05. As HCW increased, boneless loins became darker and redder, evidenced by lower L* (β₁ = −0.0243, P < 0.001) and greater a* values (β₁ = 0.0106, P < 0.001); however, HCW accounted for only ≤0.80% of the variability in loin L* and a* values. Similarly, subjective loin color score (β₁ = 0.0024, P < 0.001) increased with increasing carcass weight, but subjective marbling score was not affected by HCW (β₁ = −0.0022, P = 0.06). After 20 d of aging, HCW explained only 0.98% of the variability in loin L* values (β₁ = −0.0287, P < 0.01). Heavier carcasses had lower SSF values (β₁ = −0.1269, P < 0.001) of LM chops, although HCW explained only 4.46% of the variability in SSF. Although heavier carcasses produced loins that exhibited lower ultimate pH values (β₁ = −0.0018, P < 0.001), HCW explained only 1.23% of the variability in ultimate loin pH. Interestingly, cook loss decreased (β₁ = −0.0521, P < 0.001) as HCW increased, with HCW accounting for 5.60% of the variability in cook loss. Heavier carcasses resulted in darker, redder ham face color (P < 0.001), but HCW accounted for only ≤2.87% of the variability in ham face L* values and 0.47% of the variability in a* values. Heavier carcasses produced thicker and firmer bellies, with HCW accounting for 37.81% of the variability in belly thickness (β₁ = 0.0272, P < 0.001), 20.35% of the variability in subjective flop score (β₁ = 0.0406, P < 0.001), and 10.35% of the variability in IV (β₁ = −0.1263, P < 0.001). Overall, the proportion of variability in loin and ham quality explained by HCW was poor (≤5.60%), suggesting that HCW is a poor predictor of the primal quality of pigs within this weight range. Nonetheless, HCW was a moderate predictor of belly quality traits. The findings of this study suggest that increasing HCW did not compromise loin, ham, or belly quality attributes.