Effect of the oestrogen receptor (ESR) gene on reproductive traits of Large White, White Meaty and Landrace pigs

We investigated the effect of oestrogen receptor (ESR) gene on total number of born (TNB), number of born alive (NBA) and number of weaned (NW) piglets in Large White (LW), White Meaty (WM) and Landrace (L) sows from six Slovak breeding farms. Detection of ESR (Pvu II) genotypes was performed by the PCR-RFLP method. The frequencies of favourable B allele in LW, WM and L were 0.33, 0.25 and 0.08, respectively. We found a highly significant effect of ESR locus on NW ( P ≤ 0.01) in LW, however, we observed a negative effect of BB genotype on the trait. In WM, a positive association of B allele with TNB, NBA and NW was found but the differ - ences were not confirmed statistically. A highly significant effect of ESR locus on TNB, NBA and NW ( P ≤ 0.01) was identified only in L breed. We found an increase of +0.62 ± 0.18 (TNB), +0.65 ± 0.18 (NBA) and +0.51 ± 0.16 (NW) pigs per copy of B allele.