Effect of RYR1 and ESR genotypes on the fertility of sows of Large White breed in elite herds

e effect of RYR1 and ESR genotypes on litter size was studied in sows of Large White breed in two elite herds. e genotypes were detected by the PCR-RFLP method. In herd A in the groups of parity 1 and parity 1-6 significant differences ( P ≤ 0.01) between RYR1 genotypes in the number of all born piglets in favour of sows with CT genotypes were determined. In herd B the performance of sows CC was insignificantly better in this parameter. In herd A significant ( P ≤ 0.05, P ≤ 0.01) differences between the genotypes ESR in the groups of parity 1-6 and 2-6 were demonstrated in the number of all born, alive born and weaned piglets. e best performance was achieved by sows with DD genotypes. In herd B there were significant ( P ≤ 0.05) differences between the genotypes in the group of parity 2-6 and in the group of parity 1-6 at the significance level ( P ≤ 0.07) in the number of all born, alive born and weaned piglets, but in favour of sows with CC genotypes. e correlations between litter size and parity and year of sow birth were significant ( P ≤ 0.05, P ≤ 0.01, P ≤ 0.001).