Effect of the halothane genotype and stress on animal performance, carcasscomposition and meat quality of crossbred pigs

One hundred and twenty-eight pigs, progeny of Yorkshire-Landrace sows (NN g enotype) sired by Duroc boars (Nn genotype) representing 64 gilts (32 and 3 2 NN) and 64 barrows (32 Nn and 32 NN) were slaughtered at 104 kg liveweigh t under two management schemes: stress (S) and not stressed (NS), at 105 kg average liveweight. Feed-to-gain ratio was significantly lower (1.9%) for Nn pigs compared to NN pigs (P < 0.05). The pH-45 of S and Nn pigs were low er than NS and NN pigs, respectively (P < 0.01). Carcass yields were greate r for Nn pigs (0.5%) compared with NN pigs (P < 0.05) and S pigs displayed greater carcass yields than NS pigs (P < 0.001). Ultimate pH of the loin wa s lower for NS pigs compared with S pigs (P < 0.05). Longissimus dorsi CIE L values were greater for Nn pigs than for NN pigs (P < 0.05) and percent w ater exudate from muscle of Nn pigs was greater (38%) than for muscle of NN pigs (P < 0.001). Carcasses from Nn pigs had 2.3% more lean than carcasses from NN pigs (P < 0.05). Results of this study support previously publishe d reports on the effects of the halothane gene and demonstrate that the adv antages observed on carcass composition must be weighed against the negativ e effects on meat quality.