REPRODUCTIVE-PERFORMANCE, PROGESTERONE SERUM, AND MILK-PRODUCTION IN SPRING POSTPARTUM AWASSI AND FINN X TEXEL X AWASSI EWES

Spring postpartum reproductive performance was investigated in 19 Awas si and 15 Finn x Texel x Awassi (FTA) crossbred ewes, weaned at 2 mont hs postpartum and simultaneously exposed to rams for a period of 48 da ys. The study was conducted in 1991/92 in the Bekaa Valley of Lebanon. Postpartum FTA ewes tended to have higher fecundity and prolificacy t han those of Awassi ewes. Forty percent of the FTA ewes conceived and gave birth to 1.3 lambs per lambing, while 31.4% of the Awassi ewes co nceived and lambed (1.1 lambs per lambing). Lambing to lambing and ram introduction to lambing intervals were similar in both genotypes and confirmed that a sizeable proportion (30-40%) of Awassi ewes and their crosses may rebreed during spring postpartum anoestrus and lamb at c. 8 months interval. Furthermore, relative progesterone values revealed continuous ovarian activity in 16 % of Awassi ewes and 40 % of FTA ew es and confirmed estimates of conception in ewes. All ewes with contin uous ovulation mated and lambed. Weekly estimates of milk production o ver a 2-month period, starting the second week of lactation, showed th at daily milk yields were almost twice as much in Awassi as in FTA ewe s (P < 0.01). These results indicate the potential for Awassi ewes and their crosses to be incorporated into frequent lambing systems. Repro ductive efficiency in these ewes could be monitored efficiently by mea suring progesterone at 2-weekly intervals.