Do artificial rearing conditions of female lambs have an impact on their future maternal abilities in rangeland?
Résumé
In herbivore livestock, early experience, such as the rearing conditions of young females, may affect the robustness of their future maternal behaviour. To test this hypothesis, we studied the maternal behaviour and plasma oxytocin release of primiparous Romane ewes according to their early experience (first three months of life): artificially reared indoors without mother (AR, n=17) or maternally reared in rangeland conditions (MR, n=18). We hypothesized
that AR ewes will exhibit impaired maternal aptitudes compared to MR ones. All ewes lambed in the rangeland. Maternal aptitudes were evaluated within two days after lambing through standardised test situations. One month later, a familiar observer recorded spontaneous proximity between ewes and their lambs on the rangeland through scan sampling. On the lambing site, more AR than MR ewes stayed close to their lambs when approached by humans
(P< 0.05). In selectivity tests, all ewes were selective, rejecting a foreign lamb while accepting their own, except for two AR and one MR. Nevertheless, AR ewes appeared more disturbed in these tests, exhibiting more lamb sniffing and attempts to escape the pen (P< 0.05) than MR ewes. On the rangeland, AR and MR ewes showed similar proximity to their lambs (P=0.32). Oxytocin levels increased after lambing compared to before (P< 0.001), regardless of early
experience (P> 0.05). They were not correlated to maternal performances. Overall, our findings do not indicate that early rearing conditions affect maternal abilities of female lambs. However, they suggest they can have lasting impacts, particularly on ewes’ responses to humans.