Impact of the halothane gene on muscle quality and pre-slaughter deaths in Western Canadian pigs

The genotype with respect to the point mutation at position 1843 of the ryr-1 gene (halothane gene) and longissimus muscle quality of 1006 pigs in two Western Canadian packing plants was assessed to determine the frequency of this mutation within the commercial population and the relationship of genotype to the frequency of PSE (pale, soft, exudative) pork. The frequencies of nn (homozygous carrier), Nn (heterozygous carrier) and NN (homozygous normal) pigs within the commercial population were 0.3, 9.4 and 90.3%, respectively. Based on the subjective pork quality standards of Agriculture and Agri-Food Canada, the frequencies of paler-than-normal (colour score  3) were 21.7 and 11.2%, respectively. The frequencies of soft, exudative pork (structure score  3) were 14.8 and 7.6%, respectively. The frequency of pale loin colour was 80 and 20% higher for Nn than for NN pigs in the two packing plants, whereas the frequency...