Analysis of genetic diversity and differentiation of sheep populations in Jordan

Background Genetic diversity of sheep in Jordan was investigated using microsatellite markers (MS). Six ovine and bovine MS located on chromosomes 2 and 6 of sheep genome were genotyped on 294 individual from ten geographical regions. Results The number of alleles per locus (A), the expected heterozygosity (He) and observed heterozygosity (Ho) were measured. Overall A, He and Ho were 12.67, 0.820 and 0.684, respectively. On the other hand, genetic distances undoubtedly revealed the expected degree of differentiation among the studied populations. The finding showed closeness of three populations from south (Maan, Showbak and Tafeilah) to each other. Populations from the middle regions of Jordan (Karak, Madaba, Amman, AzZarqa and Mafraq) were found to be in one cluster. Only two populations of the middle region were an exception: AlSalt and Dead Sea. Finally, sheep populations from Irbid were located in separated cluster. It was clear that the studied predefined populations were subdivided from four populations and would be most probably accounted as ancestral populations. These results indicate that number of population is less than the predefined population as ten based on geographical sampling areas. Conclusions The possible inference might be that geographical location, genetic migration, similar selection forces, and common ancestor account for population admixture and subdivision of Awassi sheep breed in Jordan. Finally, the present study sheds new light on the molecular and population genetics of Awassi sheep from different regions of Jordan and to utilize the possible findings for future management of genetic conservation under conditions of climate changes and crossbreeding policy.

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

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)

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

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.