Genetic variation in meat quality and the incidence of malignant hyperthermia syndrome in Large White and Landrace boars

Abstract

Genetic variation in meat quality was investigated in Large White and Landrace boars in the Queensland boar performance testing station. An autosomal recessive gene of frequency 0.2 in Landrace but absent in Large White produced malignant hyperthermia syndrome (MHS) in 10 out of 206 Landrace boars given the halothane test. Muscle acidity was measured in 86 Large White and 92 Landrace carcases 1 hour (pH,) and 24 hours (pH,) after slaughter. In four Landrace litters which contained both normal and MHS boars, muscle pH was significantly lower in MHS than normal carcases. Averaged over loin, middle and neck sites of measurement, pH, values were 5.8 vs 6.3 (P < 0.01), and pH, values were 5.5 vs 6.0 (P < 0.05). The colour of the I. dorsi muscles was also paler in MHS than normal carcases (1.25 score points vs 2.5 points, P < 0.05). Excluding MHS carcases, heritability estimates of 0.33 � 0.31,0.46 � 0.30 and 0.3910.29 were obtained for pH,, pH, and colour score of the I. dorsi. There were no significant differences between the breeds in muscle acidity. Average values were 6.44 0 � 0.01 for pH, and 6.11 � 0.02 for pH,. Landrace had paler I. dorsi than Large White (2.6 points vs 2.8 points, P < 0.05). The use of meat quality measurements and the halothane test in selection programs is discussed.