Effect of Genotype and Litter Size On Discrimination of Mothers By Their Twelve-Hour-Old Lambs

Abstract

AbstractThe ability of 12-h-old Border Leicester x Merino (BL x M) and pure Merino (M) lambs to seek a ewe and to discriminate their mothers from alien dams was tested in a two choice situation. When released in a triangular enclosure at 6 m from two penned ewes placed next to each other, most lambs reached a ewe before the end of the 5-min test. BL x M lambs were more attracted to the ewes than M lambs and could better discriminate their own mothers from alien dams. Although BL x M lambs were heavier than M lambs, the differences observed were mainly related to an effect of breed rather than to birth weight. There were no significant differences due to litter size or sex within each breed. On the other hand the differences between breeds were more marked in multiple than in single born lambs. This suggests the existence of an interaction between breed and litter size in the behavioural performances of very young lambs. It is concluded that young lambs can take an active part very early in life in the normal development of selective mother-young relationships. Also, 12 hours after birth, single and multiple BLxM lambs can discriminate between their own and alien mothers better than M lambs.