Maternal behaviour in domestic sheep (Ovis aries): Constancy and change with maternal experience

Individual differences in the way ewes behave towards their lambs may help to identify the sources of variation in maternal care. In this study we inv estigated how the pattern of maternal behaviour shown by an individual anim al changed across parities in domestic sheep. The maternal behaviour of ind ividual animals (Scottish Blackface and Suffolk sheep), in the first 2 hour s after lambing, was compared when lambing as primiparous and multiparous e wes. More rejecting behaviours (e.g. withdrawal, aggression, lack of co-ope ration with lamb sucking attempts) were expressed by ewes in their first pa rity than in subsequent parities. Behaviours associated with affiliation an d bonding (e.g. grooming attention) were not, however, significantly influe nced by parity within individual ewes. Principal Components Analysis of mat ernal behaviours was carried out on behavioural data from primiparous and m ultiparous ewes. In common with studies in primates, behaviours in both pri miparous and multiparous ewes were clustered on two main axes or Factors, l abelled 'maternal rejection' and 'maternal care/warmth'. However, in multip arous ewes, a third Factor, labelled 'aggression', was found whereas in pri miparous ewes aggressive behaviours loaded on the same dimension as 'matern al rejection'. Behavioural consistency was investigated by correlating the behavioural data from primiparous and multiparous individuals. There was a significant correlation between the scores received by primiparous and mult iparous ewes for both the 'care/warmth' and the 'rejection' dimensions of m aternal behaviour. Our data suggest that, in sheep, maternal behaviours are segregated along the twin axes of 'rejection' and 'care/warmth'. Although the frequency of rejection behaviours declined with maternal experience, in dividual ewes were consistent in their expression of maternal care across p arities, suggesting that the maternal behaviour of a primiparous ewe is rea sonably predictive of her behaviour in subsequent pregnancies.