Culling of gilts with special reference to reproductive failure.

The present investigation comprised 2041 gilts (Swedish Landrase + Swedish Yorkshire) selected for breeding purposes at 10 weeks of age belonging to one large herd in Sweden. Of all selected gilts 54.5% were culled without farrowing any litter. The reproductive disturbances represented 21.7% of the cullings and together with slow growth rate, high backfat thickness and inverted teats, constituted the main reason for culling. In gilts above 9 months of age 66.9% of the cullings were caused by reproductive disturbances, anoestrus being the dominating reason. Only 2.8% of gilts born during July-September were culled because of oestrous failure, while the corresponding figure for gilts born during January-March was 9.6% (p less than 0.001). Furthermore a highly significant annual variation was found among gilts culled because of anoestrus (p less than 0.001). Among expected pregnant gilts 6.6% were culled because of failure to farrow.