Effect of restricted suckling upon post-partum reproductive activity in sheep

The post-partum reproductive performance of adult West African ewes of proven fertility was studied to assess the beneficial effect of both 14 and 18 h restricted nursing or early weaning (35 days post-lambing) on the resumption of ovarian function and conception rate at first oestrus. Although the interval from lambing to first oestrus and/or conception in the 14 h nursing (55.13±11.03 days), 18 h nursing (65.00±15.65 days) and control (59.00±13.48 days) groups did not differ, the percentage of ewes that showed oestrus (90, 60 and 50% respectively) favoured the treatment with the shortest nursing time. When lambs were weaned early, the interval from lambing to oestrus (61.40±16.50 days) did not differ significantly from that for the 14 h nursing ewes (70.10±19.37 days) but tended to be lower than for the controls (94.25±62.38 days). Since differences in response were assumed to be dependent on body condition of the individual ewes at the time of lambing, and body weight changes of the dams after lambing were correlated with progesterone hormone, plasma proteins, glucose and free fatty acids, it was assumed that the beneficial effects of the treatments on the reproductive parameters were due to the partition of nutrients towards restoration of body reserves and subsequently to the secretion of progesterone. (author). 27 refs, 2 figs, 3 tabs