Reproductive performance of Polish Large White sows in intensive production - effect of parity and season

Abstract

The lifetime reproductive performance of 79 Polish Large White sows, kept at a large commercial farm was analysed according to age, parity and season. Reproductive indices of the sows changed significantly with age, but the direction of these changes depended on the parameter analysed. Conception rate, gestation length, number of stillborn piglets and number of piglets that died before weaning increased over successive parities. The weaning to conception period and the reproductive cycle decreased as sows became older. Total and live born litter size were increasing up to the 5th parity and then decreasing, but the decline of total born litter size was slight and the decrease in liveborn litter size was more rapid and statistically significant. Differences between seasons were smaller and most noticeable in the conception rate. Best results were obtained by sows mated in the autumn and poorest by summer-mated sows.