Weaning and the ram-effect on fertility, serum luteinizing hormone and prolactin levels in spring rebreeding of postpartum Awassi ewes

Spring rebreeding activity was investigated in 44 multiparous Awassi ewes a llocated to one of three treatments. The first treatment entailed ewes suck ling lambs for 45 days and then continuously exposed to fertile rams (Group 1): ewes of the second group were weaned at 14 days of age and then were e ither exposed continuously (Group 2) or intermittently (Group 3) to rams. T ime of weaning and type of exposure to the ram did not influence the reprod uctive performance in terms of fertility and prolificacy in postpartum Awas si ewes. Time of weaning did not influence serum LH concentrations monitore d at 3 h intervals in Groups I and 2. However, serum prolactin (PRL) concen trations were significantly higher in Group 1, compared to Group 2 of ewes. Serum LH levels at weaning were significantly higher in ewes that conceive d and lambed, compared to ewes that did not. It was concluded that spring r ebreeding of postpartum Awassi ewes did not respond to ram presence and/or early weaning in terms of improved reproductive performance, The lack of re productive response was further reflected in LH and PRL profiles. (C) 2001 Elsevier Science B.V. All rights reserved.