Analysis of prolificacy in sows of hyperprolific lines of Large White breed

The objective of the paper was to evaluate the results of reproductive performance of sows in some elite breeding herds of the Large White breed included in experimental herds for the production of hyperprolific lines of dam breeds. The set consisted of 98 sows with the known genotypes of ESR, FSHβ and PRLR genes. The dendrogram shows that on the basis of their genetic outfit the sows can be divided into two clusters. The first cluster can be described as a cluster with marked dominance of HPL sows and the second cluster with marked dominance of the sows of basic herd. The first cluster consisted of individuals in which the preferred genotype AA of PRLR gene was not detected. As for FSHβ gene, the beneficial genotype BB was found out in 74.10% of sows. In ESR gene the beneficial genotype DD was recorded only in 11.10% of individuals. On average for the lifetime performance they delivered by 2.08 piglets more in all born piglets and by 1.96 piglets more in live-born piglets per litter. Differences in the reproductive traits between HPL sows and the sows of basic herd in the first cluster were statistically highly significant. On the contrary, genotype AA of PRLR gene was identified in all sows of the second cluster, 61.36% of animals possessed beneficial genotype BB of FSHβ gene. As for ESR gene, beneficial genotype DD was identified within the whole cluster in 31.82% of sows. In lifetime performance the HPL sows had on average by 1.10 individuals more in all born piglets and by 1.01 more in live-born piglets (statistically significantly higher values). The unambiguous expression of a positive effect of preferred genotypes of selected candidate genes failed to be confirmed by the results of statistical analyses testing the associations of candidate genes for pig reproduction with selected parameters of breeding value and prolificacy of sows.