The significance of the vomeronasal organ for offspring recognition in sheep

Three groups of 10 Dorset ewes each were randomly selected to determine the importance of the vomeronasal organ for offspring recognition during nursing. The ewes in treatment group 1 were rendered anosmic by two irrigations of their olfactory mucosa with a zinc sulfate–procaine solution. The vomeronasal organs of the ewes in treatment group 2 were rendered nonfunctional by electro-cauterization of the nasoincisive duct. The nasal cavities in the ewes in treatment group 3 were just irrigated with normal saline. Each ewe received a 1-day-old alien lamb and nine behavioural recordings were collected for the 10-min trial. Analyses of variances revealed that the ewes with non-functional vomeronasal organs were unable to distinguish alien lambs from their own and allowed alien lambs to suckle as if they were their own lambs. Both groups with functional vomeronasal organs rejected alien lambs at the udder. Thus, it was concluded that the vomeronasal organ is used as a final determinant for offspring recognition during nursing in sheep. © 2005 Elsevier B.V. All rights reserved.