The aims of this study were first to define five behaviour traits which characterise the mothering abilities
of sows and subsequently to obtain estimates of variance components and breeding values for these traits in order to assess the suitability of the traits as selection criteria. Finally, genetic correlations between litter size at birth and the behaviour traits were estimated in order to test if selection for improved maternal behaviour is associated
with number of piglets born alive. It was found that including maternal behaviour in breeding programmes requires appropriate traits. These must be precisely defined, as objectively as possible, easy to record on a large scale and sufficiently genetically determined. From the five defined and analysed traits in the present study crushing seems to be themost promising trait for selection. Even though the estimated heritability was low, it shows a high incidence and is relatively easy to record objectively on a large scale.