Abstract
Reproductive performance was studied in 40 multiparous Awassi ewes, weaned during their first week postpartum (Regime A), or at 2 months postpartum (Regime B), In both regimes, ewes were simultaneously exposed to rams after weaning, for a period of 48 days. In Regime A, early weaning did not improve reproductive performance in fertility and prolificacy; however, it indicated their potential to breed during early postpartum and lamb at 6-month intervals, Both regimes resulted in ewes conceiving at an average of 30 days after ram introduction. The peripheral progesterone concentrations in ewes, monitored at biweekly intervals after ram introduction, ranged from 0.14 +/- 0.02 ng ml(-1) to 2.95 +/- 0.72 ng ml(-1), during the first 2 months postpartum (Regime A ewes), and from 2.5 +/- 0.73 ng ml(-1) to 3.85 +/- 0.82 ng ml(-1), during 2-4 months postpartum (Regime B ewes). Subsequent lambing dates confirmed estimates of conception based on progesterone concentrations. Progesterone values revealed that 18% of Awassi ewes remained in anestrus (progesterone level was less than 0.5 ng ml(-1)), with no response to either Regime A or B; the rest showed variable degrees of cyclicity. However, only 28% of the ewes conceived and lambed. Only three ewes (8%) showed continuous cycling activities, conception, and subsequent lambing, It was concluded that ovulatory activity in spring postpartum Awassi ewes is not always associated with successful conception and lambing.