Barrows (n = 2,178) and gilts (n = 2,274) were fed either high-energy or low-energy diets from 27 kg of BW to target BW of 118, 127, 131.5, and 140.6 kg over 12 monthly replicates. Carcass primal cut and subprimal cut weights as well as optical probe backfat and loin depth measurements were collected on each pig. The cut weights and carcass measurements for each pig were fitted to allometric functions (Y = A · CWB) of carcass weight (CW), where A is a scalar parameter and B is the allometric coefficient. The final models were weight or measurement = random effect of replicate + (1 + bDD) · (A · CWB) + error, where bD is the regression coefficient, D (diet) = −0.5 for the low-energy and 0.5 for high-energy diets, and A and B are sire line–sex specific parameters. Linear regressions of backfat and loin depth residuals from the model were included at P < 0.05 to the cut weight equations but had little effect to reduce the residual variance. The residuals among the primal and subprimal cuts were correlated, and a Cholesky decomposition procedure was used on the variance–covariance matrix of the residuals. By using these procedures, a stochastic model can be used to evaluate the effect of alternative management, marketing, and carcass sorting strategies on the mean and distribution of pork primal and subprimal cut weights to increase pork processor profitability.

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.

Pigs from four sire lines were allocated to a series of low energy (LE, 3.15 to 3.21 Mcal ME/kg) corn-soybean meal-based diets with 16% wheat midds or high energy diets (HE, 3.41 to 3.45 Mcal ME/kg) with 4.5 to 4.95% choice white grease. All diets contained 6% DDGS. The HE and LE diets of each of the four phases were formulated to have equal lysine:Mcal ME ratios. Barrows (N = 2,178) and gilts (N = 2,274) were fed either high energy (HE) or low energy (LE) diets from 27 kg BW to target BWs of 118, 127, 131.5 and 140.6 kg. Carcass primal and subprimal cut weights were collected. The cut weights and carcass measurements were fitted to allometric functions (Y = A CWB) of carcass weight. The significance of diet, sex or sire line with A and B was evaluated by linearizing the equations by log to log transformation. The effect of diet on A and B did not interact with sex or sire line. Thus, the final model was B) where Diet = −0.5 for the LE and 0.5 for HE diets and A and B are sire line-sex specific parameters. cut weight = (1+bD(Diet)) A(CW Diet had no affect on loin, Boston butt, picnic, baby back rib, or sparerib weights (p>0.10, bD = −0.003, −0.0029, 0.0002, 0.0047, −0.0025, respectively). Diet affected ham weight (bD = −0.0046, p = 0.01), belly weight (bD = 0.0188, p = 0.001) three-muscle ham weight (bD = −0.014, p = 0.001), boneless loin weight (bD = −0.010, p = 0.001), tenderloin weight (bD = −0.023, p = 0.001), sirloin weight (bD = −0.009, p = 0.034), and fat-free lean mass (bD = −0.0145, p = 0.001). Overall, feeding the LE diets had little impact on primal cut weight except to decrease belly weight. Feeding LE diets increased the weight of lean trimmed cuts by 1 to 2 percent at the same carcass weight.

The objective of this study was to characterize the quality attributes of pork derived from pigs of the following backgrounds: Duroc, Pietrain (Halothane negative, NN), Pietrain (Halothane positive, nn), Berkshire, Hampshire (rn+), Hampshire (RN−), and a synthetic line. A 10-member panel was trained to evaluate visual appearance of uncooked lean and fat, and flavor and texture of cooked chops. Hunter L*, a*, and b* values, hue angle, cookloss and Warner–Bratzler shear force were also determined. Visual color differences occurred due to genetic background. Chops from Duroc, Berkshire, Pietrain-nn, and the synthetic line were least pink. Chops from Berkshire carcasses appeared to have the most marbling in the lean and those from Pietrain-nn pigs appeared to have the least. Chops from Pietrain-nn and Hampshire-rn+ carcasses had the highest a* values while chops from Duroc, Pietrain-NN, and Hampshire-RN- carcasses had the lowest. Cook loss from chops from Duroc carcasses was lower than that from Hampshire rn+, Pietrain-NN and synthetic line carcasses. Shear force was highest for chops from Pietrain-nn and Hampshire-rn+ carcasses. Chops from Hampshire-RN− carcasses were most juicy followed by those from Hampshire-rn+, Pietrain-NN, Berkshire and Duroc carcasses. Shear force was positively correlated with abnormal flavor intensity, metallic taste, and chewiness (r=0.72, 0.94, and 0.69, respectively), and negatively correlated with sweetness (r=−0.73). Overall, genetic background had significant effects on many of the quality characteristics evaluated.