Reproductive Performances and Survival of Washera Sheep under Traditional Management Systems at Yilmanadensa and Quarit Districts of the Amhara National Regional State, Ethiopia

摘要

On-farm data were collected to evaluate reproductive performance and survival of Washera sheep raised under traditional smallholder production systems in the North-Western highlands of the Amhara National Regional State, Ethiopia. The data were from flocks of 110 households from October, 2004 to September, 2007. Mean age and weight at first lambing were 464.2±14.0 days and 24.7±0.5 kg, respectively. None of the fixed effects considered affected age at first lambing although, weight at first lambing was affected (p<0.05) by district and parity. Ewes from primiparous ewes and from Quarit district had heavier weight at their first lambing. Lambing interval (269±6.2 days) was affected by district, lambing season, parity and birth type. The average number of lambs per ewe lambing was 1.19±0.02 and varied (p<0.0001) with lambing year and postpartum ewe body weight. Mean postpartum ewe body weight was 31.0±0.2 kg and influenced (p<0.01) by district, year, season, parity and type of birth. Cumulative survival from birth to 30, 90, 180, 270 and 365 days was 98.4±0.6, 93.6±0.9, 91.2±1.1, 90.0±1.2 and 89.9±1.2 days, respectively. Except at the age of 30 days, district, season, birth type and birth weight affected (p<0.05) survival. No interactions between any fixed effects were significant and thus were removed from the model. Postpartum ewe body weight as a covariate did not affect litter size. The higher survival rate indicates that the area is of low disease load and the farmers practice to decrease lamb mortality need to be encouraged and improved. The influence of different fixed effects on reproductive performances indicated that through different management and breeding practices it is possible to increase the productivity of these breed of sheep.