Study Of Effect Factors On Number Born Alive And Selection Technique Of Sow

study the number of birth alive piglets (NBA) and the influencing factor, the 1170 litters from 729 Sows (Duroc, Large White, Landrace) were recorded respectively. The results showed that:1. The NBA was higher in the range from 4 to 7 parties in spring in Duroc, Yorkshire and Landrace.2. The NBA of the Duroc sow was related with genes of ESR and RYR1. The ESR's gene types of BB and AB were not correlated with the number of piglets compared to the sow with the genotype of AA. The NBA of the sow with genotype of NN was higher than the sow with nn genotype.3. The results of the ESR and RYR1 genes in Large White were the same with the Duroc.4. Molecular markers assistant selection and routine method were both used in sow selection of Landrace crossed with Large White. After the sows were selected by routine method, Molecular markers assistant selection of RYR1 gene could improve the litter size. The result in this study should need more experiments.