Conservation and utilization of germplasm resources of Shandong local chickens.

[Objective] To evaluate lactation performance of primiparous Nubian ewes and Yunling Black ewes.[Method] Healthy primiparous Nubian ewes(20 ewes lambing twins and 19 ewes lambing single) and Yunling Black ewes(4 ewes lambing twins and 15 ewes lambing single) were used to study the effects of breeds and litter size on lactation performance.[Result] The total milk yield of the Nubian ewes lambing twins was 14.81% higher than that of the Nubian ewes lambing single(P0.05) and 22.93% higher than that of the Yunling Black ewes lambing twins(P0.05).The total milk yield of the Yunling Black ewes lambing twins was 32.80% higher than that of the Yunling Black ewes lambing single(P0.05),but the total milk yield of the Nubian ewes lambing single was 42.20% higher than that of the Yunling Black ewes lambing single(P0.05).The Nubian goats and the Yunling Black goats had similar lactation curves.The milk yield gradually increased during the early lactation period(5-15 d post partum),and the lactation peak lasted for 20 d(15-35 d post partum).Then the milk yield gradually decreased.The predicted values showed the milk yield of the ewes may rapidly decrease during 80-120 d post partum.Until Day 70 post partum,the Nubian ewes lambing twins had lost 3.06% more body weight than those lambing single had(P0.05);the Yunling Black ewes lambing twins had lost 0.89% more body weight than those lambing single had(P0.05).The Nubian ewes lambing lost 3.22%-5.39% more body weight than those with the same litter size did(P0.05).[Conclusion] The regular pattern of primiparous lactation is similar between the Nubian ewes and the Yunling Black ewes,and their lactation performance is closely related to breeds and litter size.