Genetic parameters and trends of meat quality, carcass composition and performance traits in two selected lines of large white pigs

Meat quality, carcass composition and performance traits were measured in two selection lines selected for either low backfat thickness (BF) at a fixed live weight or high live weight (WEIGHT) at a fixed age. The performance traits were measured on 3966 to 3985, carcass composition trait on 278 and meat quality traits on 426 to 490 pigs. The meat quality traits were: pH, measured 45 min and 24 h after slaughter in M. semimembranosus and M. longissimus, filter paper score and filter paper weight measuring water-holding capacity, Japanese colour scale and Hunter's colour measurements and a marbling score. Phenotypic and genetic correlations with meat quality traits were higher for lean percentage (LEAN%) and WEIGHT than for BF. From the genetic correlations between performance and meat quality traits and the correlated genetic response of meat quality traits to selection for performance traits, it was concluded that deterioration of meat quality over many generations occurs. Correlations indicate that BF as an index trait for leanness would result in less deterioration of meat quality than when selecting for LEAN%. The genetic trends showed that selection for WEIGHT resulted in more deterioration of meat quality than selection for BF. A pH measurement 45 min after slaughter could be a good indicator for improving water-holding capacity