Reproductive characteristics of Awassi ewes mated artificially or naturally to Jordanian or Syrian Awassi rams en

ABSTRACT

A total of 586 Awassi ewes of varying ages were mated to 11 Jordanian and 11 Syrian Awassi rams either naturally or artificially during the normal breeding season to evaluate reproductive performance of Awassi sheep and compare the local Awassi rams toSyrian rams. The length of the estrous cycle was longer (P < 0.01) during June to July (28.6 + 0.9 d) than August to September (17.8 + 0.7 d). Syrian-sired matings resulted in a greater lambing rate to the first mating within breeding season than Jordanian-sired matings (P < 0.05), but not for the second, third, or fourth mating. The cumulative lambing rate after the fourth mating tended to be greater (P < 0.1) using Jordanian compared to Syrian sires. The number of single lambs per ewe lambing was significantly (P < 0.001) greater than multiple births. Birth, weaning, and marketing weights and average daily gain before weaning were significantly greater in single (P < 0.001) and male-lamb (P < 0.05) pregnancies than in twins and females. An increase (P < 0.01) in the average daily gain during the lambing season was observed in November and December compared to January, February, or March. The overall mortality rate was 21%, and there was a decrease (P < 0.001) from 1 to 3 yr of age and an increase (P < 0.01) from November to March. Jordanian and Syrian rams yielded similar reproductive characteristics except for the lambing rate of first mating. Lambs born early in the season had better (P < 0.01) average daily gain and lower (P < 0.001) mortality than those born later.(AU)