Effect of halothane genotype, breed, feed withdrawal, and lairage on pork quality of belgian slaughter pigs.

A total of 434 Belgian Landrace (B) or Piétrain x B (PB) pigs, of known halothane genotype (NN, Nn, and nn), were slaughtered in a commercial abattoir. Pigs were either fed until loading or deprived of food overnight before delivery. Upon arrival at the abattoir, pigs were slaughtered after different lairage times (within 1 h after arrival, after 2 to 3 h lairage, or 4 to 5 h lairage). Meat quality traits were measured on the carcass, as well as on a piece of loin. Halothane genotype was the predominant factor determining meat quality traits related to the PSE condition (P < .001 for pH 40 min after death, internal reflectance, color L value; P < .01 for drip losses, transmission value). For these traits, nn pigs were always significantly different from Nn and NN pigs. Depending on the specific trait, Nn pigs were intermediate between NN and nn pigs, or close to NN pigs. For pH 40 min after death and drip losses, Nn and NN pigs were significantly different, whereas the difference between Nn and NN pigs was not significant for internal reflectance, color L value, and transmission value. Shear force and intramuscular fat content were apparently not related to the PSE condition and were not influenced by the halothane genotype (P > .05). Differences in meat quality between B and PB pigs and between gilts and barrows were rather unimportant compared with the effect of halothane genotype. Overnight feed withdrawal had no effect on meat quality (P > .05 for all PSE-related traits). On the other hand, holding pigs a few hours in lairage improved meat quality compared with immediate slaughtering (P < .05 for pH and temperature in the loin 40 min after death, internal reflectance, color L value, transmission value, drip losses). This effect was more pronounced in stress-susceptible pigs than in stress-resistant pigs.