Genetic analysis of litter size and weights, and of farrowing duration in Large White and French Landrace sows

Low heritability estimates were obtained for litter size and mortality traits. Numbers of piglets stillborn had unfavourable geneticcorrelations with Numbers of piglets born in total, but low genetic correlations with Numbers of piglets born alive. Both Numbers of piglets born in total and Numbers of piglets born alive showed a genetic antagonism with Survival rate. The Number of stillborn was positively correlated with Farrowing duration at the genetic level. Litter weight was positively correlated with Litter size and had low (French Landrace) to moderate (Large White) genetic correlations with Survival rate. Standard deviation of individual piglet weight was genetically associated with lower Survival rate.