An evaluation of a terminal sire line for feedlot performance, carcass composition, and meat quality

Abstract

Three QM Hamline™ (HL; National Pig Development, Canada), four pure-bred Landrace (LR) and Large White (LW) sires were bred to 12, 18 and 8 Manor Hybrid™ (National Pig Development, Canada) sows, respectively, which provided 37 NN-, and 37 Nn- HL, 39 NN- and 37 Nn- LR and 34 NN- LW commercial pigs for a study on the effect of breed of sire and genotype at the halothane locus on pig performance, carcass yield and meat quality. Four pigs per pen, within breed of sire and genotype, were placed on performance test at 56 d of age until total pen weight was 440 kg. Large White, LR and HL NN-pigs were slaughtered at 178, 172 and 177 d of age, adjusted to 110 kg, while LR and HL Nn-pigs were slaughtered at 177 and 178 d of age. HL pigs had 12.7 mm backfat and 44.5 mm of muscle depth at the grade site, while LW and LR had greater backfat thickness (15.1 and 15.7 mm), and less muscle depth (41.1 and 38.7 mm). The halothane genotype did not affect live animal measurements. Feed utilisation was similar in all five groups of pigs. Lean yield of the HL NN-pigs (58.8%) was greater than that found in the NN-LW (56.6%) and NN-LR (56.8%) while the halothane gene made only modest improvement in lean yield in the leaner HL (P = 0.0789) and a more substantial improvement was observed in the fatter LR (P = 0.0161). Total dissected lean was 613, 596, and 639 g kg−1 in LW, LR and HL NN-pigs, respectively, while this increased to 611 and 649 g kg−1 in LR and HL Nn-pigs. QM Hamline™ NN-pigs had larger commercial hams (9878 g) compared with NN-LW and NN-LR sired pigs. Furthermore, they also had greater lean yield in all four lean cuts. The halothane gene had no consistent effect on carcass merit. While initial pH was similar (6.03–6.04) in the three NN-groups of pigs, it dropped to 5.73 and 5.84, among the Nn-LR and HL pigs. Luminosity (59.2%, 58.7%) and hue angle (31.1°, 30.5°) of Nn-LR and HL were higher, with greater drip (5.8%, 5.3%) losses and lower soluble protein (130, 148 g kg−1), compared with NN-LR (54.8%, 24.4°, 3.0%, 185 g kg−1) and HL (55.3%, 26.1°, 3.4%, 182 g kg−1) pigs, respectively. This study indicates carcass merit can be substantially improved without use of the halothane gene and without serious effects to meat quality. However, introduction of the halothane gene can seriously compromise meat quality. Key words: Large White, Landrace, Hamline, halothane gene