Olfaction mediates the establishment of selective bonding in goats

Abstract

Nine pregnant goats of the Creole breed were rendered anosmic 3 weeks before parturition by irrigating their olfactory mucosa with zinc sulfate, and nine additional pregnant goats were left intact. At parturition, interactions between all females and their young were observed for 1 h. No differences were found in mother-young relationships between intact and anosmic mothers during this time, except that kids from anosmic females were slower to suck than controls. After 4 h of uninterrupted mother-young contact, mothers underwent three successive-5-min tests in a predetermined order to study selective bonding: with their own kid, an alien kid of similar coat color and pattern, and an alien kid of dissimilar coat color and pattern. Intact goats readily discriminated between kids, and rejected the two aliens while accepting their own. By contrast, anosmic mothers showed no signs of discrimination and accepted the three types of kids. It is concluded that during the first postpartum hours of contact, mother goats memorize individual olfactory characteristics of their kid that serve as a basis for selective suckling and exclusive bonding. Furthermore, at this early stage, visual characteristics of the young do not appear able to compensate for the loss of olfactory cues.