EFFECTS OF AN ENRICHED ENVIRONMENT ON SUBSEQUENT FEAR REACTIONS OF LAMBS AND EWES

The effects of an enriched enviornment (EE, permanent presence of a hu manlike model plus colored mobile objects) during the rearing period ( fr om birth to weaning at 3 months) were assessed on subsequent fear r eactions of lambs and their mothers. Behavioral tests involved isolati on, surprise effect, and the presence of a human?. Fear,reactions of d am-reared (DR) lambs from the EE did not differ from controls. By cont rast, their mothers showed a long-lasting reduction bl fear reactions as compared with controls. Artificially reared lambs (AR, in the absen ce of the mother) placed in the same EE were proved to be less fearful tlzal? controls. Finally, no effect of the same EE was found in cycli c ewes. In conclusion, differences between,results obtained in AR and DR lambs may be due to the strong mother-young bond which would minimi ze the impact of the environment. rn ewes, there might exist some kind of sensitive period between parturition and weaning during which the female may be more sensitive to her physical environment. (C) 1998 Joh n Wiley & Sons, Inc.