Genetic correlations between mortality rate and other litter traits of the sow

Abstract

Litter mortality rate until weaning should be low in order to have a high number of piglets weaned. This trait has been analysed in two recent studies (Hermesch et al., 2001; Knol, 2001). Genetic correlations of litter mortality with average piglet weight at birth and within litter variation of birth weight differ between these two studies, which may be partly due to different trait definitions for litter mortality. Knol (2001) defined litter mortality as the percentage of a litter that died before weaning (MORT%). In contrast, Hermesch et al. (2001) analysed the number of piglets that died per litter (NDIED). This study presents genetic correlations between MORT% and litter traits of the sow.