Dependence of sows’ productivity on the reason of their culling, in index selection

When studying the dependence of the lifelong productivity of sows on the reason of their culling in index selection, we detected no significant effect of culling due to technological and veterinary reasons on the change in the percentage of high-productive animals in the herd. Credible differences in the number of piglets born per litter among sows culled for various reasons were detected only between groups of sows culled due to age and selection (10.1% with p <0.01). These differences prove the validity of the culling at the level of the estimated generation. Also the productivity of sows was evaluated in individual farrows. The peak of sows' productivity is marked at the period from the fifth to the seventh farrows. Credible differences between the sows' productivity in the first two farrows and the following ones were established.