Olfactory Preferences in Newborn Lambs: Possible Influence of Prenatal Experience

Abstract

Abstract The present study examined whether prenatal chemosensory experience influenced chemosensory-based orientation behaviour in newly-born lambs. Two experimental strategies were developed in order: (i) to analyse the responsiveness of lambs to odours extracted from the prenatal environment (experiments 1 and 4) and to odours their were never exposed to (experiment 2), and (ii) to analyse the neonatal consequences of a prenatal exposure to a novel odorant (experiment 3). In experiment 1, when simultaneously presented with amniotic fluid (AF) and distilled water in a double-choice test, lambs displayed a clear attraction to AF. In experiment 3, two groups of lambs received differing exposure to citral in utero: group I lambs were born to ewes fed a citral diet and group 2 lambs were born to ewes never exposed to citral (CI). They were assessed in a double-choice test contrasting CI and AF (experiment 2 indicates that CI was neither attractive nor aversive in naive lambs). Although control lambs showed a clear preference for AF over CI, those exposed to CI prenatally did not orient discriminately to either stimulus, suggesting that prenatal experience with CI may alter postnatal responsiveness to it. Experiment 4 tested the ability of lambs to discriminate between the chemosensory qualities of samples of own vs alien AF; lambs oriented preferentially to their own AF. These findings suggest that prenatal chemosensory experience may be stored by lambs for some time after birth and influence their search behaviour.