[Genetic analysis of sow productivity traits]

Genetic analysis was conducted on the data of 3 populations with 1686 litters including Erhualian pigs, Large White and first cross. The phenotypic and genetic parameters among litter weight at birth (LW), average piglet weight at birth (APW), litter weight at 20 days (LW20), average piglet weight at 20 days (APW20), litter weight at 45 days (LW45), average piglet weight at 45 days (APW45) were estimated by sire model. The results indicated that Erhualian pigs had stronger maternal ability and slower growth rate compared to Large White. The first four traits (LW, APW, LW20, APW20) had larger maternal effects, while LW45 and APW45 had smaller maternal effects. The heritabilities of LW, APW, LW20, APW20, LW45, APW45 were 0.251, 0.277, 0.341, 0.330, 0.235, 0.186, respectively. The results indicated that direct selection was effective. According to our results, we considered that it was fit to select two traits (LW, LW20) out of these six traits to reflect sow productivity. Litter weight at birth could reflect the prolificacy of sow, litter weight at 20 days could reflect the maternal ability of sow.