Relationship between swine production traits measured in live animals at probing age and their carcass quality
Genetic correlations between production and carcass quality traits measured in purebred pigs were estimated using the derivative free multiple trait restricted maximum likelihood procedure. Phenotypic correlations between both production and carcass traits were also determined. Two performance traits (body weight and the average backfat thickness adjusted to 100 kg), one carcass trait (estimated lean yield percentage), and four meat quality traits (colour, marbling, structure and drip loss) were analyzed. Data were from the Ontario Pork Carcass Appraisal Project. The performance, carcass and meat quality data contained 3037 records, while a subset of the data (1933 records) was used for the evaluation of muscle colour by spectrocolorimetry. Genetic correlations of backfat thickness and colour scores were positive and ranged from 0.11 to 0.30. Genetic correlation of backfat thickness with marbling was 0.51. Genetic correlations of meat quality traits and estimated lean yield percentage were negative. Phenotypic correlations between meat quality, except for marbling, and performance traits measured on live animals were about zero, indicating no phenotypic relationship. The genetic correlations between meat quality traits and colour coordinates measured with a spectrocolorimeter were variable, which may be attributed to sampling error. Results showed a negative genetic relationship between meat quality and estimated lean yield percentage, suggesting that decreasing backfat thickness will result in decreased meat quality. There is the potential to improve meat quality in swine using the genetic variability of meat quality and carcass traits and their genetic correlations with production traits. Construction of an economic index that includes production and meat quality traits would help to decrease backfat, and also maintain or improve meat quality for greater consumer acceptance.