Effects of an enriched environment of subsequent fear reactions of lambs and ewes.
The effects of an enriched environment (EE, permanent presence of a humanlike model plus colored mobile objects) during the rearing period (from birth to weaning at 3 months) were assessed on subsequent fear reactions of lambs and their mothers. Behavioral tests involved isolation, surprise effect, and the presence of a human. Fear reactions of dam-reared (DR) lambs from the EE did not differ from controls. By contrast, their mothers showed a long-lasting reduction in fear reaction as compared with controls. Artificially reared lambs (AR, in the absence of the mother) placed in the same EE were proved to be less fearful than controls. Finally, no effect of the same EE was found in cyclic ewes. In conclusion, differences between results obtained in AR and DR lambs may be due to the strong mother-young bond which would minimize the impact of the environment. In 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.
I.N.R.A. Laboratoire d'Etude du Comportement Animal Physiologie de la Reproduction, Nouzilly, France.
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Vandenheede
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Bouissou
D000818:Animals; D004777:Environment; D005239:Fear / Q000502:physiology*; D005260:Female; D008297:Male; D008425:Maternal Behavior / Q000523:psychology; D009769:Object Attachment; D011581:Psychological Tests; D012756:Sheep; D012934:Social Isolation / Q000523:psychology