Interactions between normal ewes and newly born lambs deprived of visual, olfactory and tactile sensory information

Abstract

Fifty-seven Merino and crossbred ewes were observed with their lambs for 1 h after birth to establish whether visual, olfactory or tactile sensory stimulation is the more important for teat location and sucking. The main observations made were, for the lamb, standing, nosing of the ewe and sites nosed, and sucking; for the ewe they were licking of the lamb and sites licked. A group of 12 ewe/lamb pairs in which each lamb was blindfolded at birth showed that these lambs failed to approach the ewe and some did not stand, although all approached the udder and sucked very quickly after the blindfold was removed. Eleven lambs fitted with a control blindfold with holes cut for the eyes did not differ from untreated controls. A group of 11 in which the lambs' nasal passages were sprayed with 10% aerosol xylocaine differed from the 11 controls in that fewer treated lambs sucked within the test period. The behaviour of 12 lambs whose upper lips were anaesthetised with xylocaine differed from controls in time to first touch on the udder and in sucking. Results are discussed in terms of the importance of visual stimulation in the lamb's initial approach to the ewe, and also of the role of the lamb in eliciting maternal attentiveness and differences between the maternal behaviour of Merino and crossbred ewes, part of which may be imputed in the present work to the vigour of the lambs.