Genetic parameters for lean meat yield, meat quality, reproduction and feed efficiency traits for Australian pigs: 3. Genetic parameters for reproduction traits and genetic correlations with production, carcase and meat quality traits

Genetic parameters were obtained using REML procedures applied to a multiple trait animal model for number born alive (NBA), litter birth weight (LBW), average piglet weight at birth (ABW) recorded in the first, second and third parity (NBA1,2,3, LBW1,2,3, ABW1,2,3) and 21-day litter weight (LW211) for 6050 Large White and Landrace sows. Heritability estimates ranged from 0.06 to 0.22 for these reproductive traits, with lowest estimates for NBA1,2,3 and LW211. Reproductive performance in the first parity should be regarded as a different trait than reproductive performance in later parities (range of genetic correlations (rg): 0.52–0.78, ±0.16–0.30). NBA1,2,3 was unfavourably related with LBW1, ABW1,2,3 and LW211. In addition, NBA1,2,3 was negatively correlated with growth rate traits, feed intake and weight of the back leg and ham (BLW, LMW) (rg range: −0.45 to −0.01, ±0.13–0.15). In contrast, genetic correlations were favourable between LBW1,2,3, ABW1,2,3 and growth rate, BLW and LMW (rg values: 0.08–0.55, ±0.12–0.25). NBA1,2,3 and ABW1,2,3 were not genetically related with backfat measurements, while a low backfat was associated with a high LBW1,2,3 (rg: −0.54 to −0.08, ±0.09–0.36). Genetic correlations between reproduction traits and meat quality traits were inconsistent between traits and parities. A lower intramuscular fat content was associated with a higher LBW1,2,3 and ABW1,2,3 (rg: −0.37 to −0.12, ±0.12–0.18). In summary, genetic correlations between reproduction traits and performance traits were only unfavourable between litter size and growth rate and feed intake. Genetic correlations between litter birth weight and average piglet weight at birth indicate that selection for leanness will also improve litter weight traits.