Dietary Protein on Growth Performance, Serum Biochemical Index and offspring of Hu ewes in late pregnancy

The purpose of this study was to explore the effects of ewe growth performance, serum biochemical indicators and lamb growth and development at different protein levels in late pregnancy. A total of 15 pregnant ewes (46.4 {+/-} 1.38kg initial BW) were assigned to 3 groups with 5 ewes in each group in a randomized block design. P1, P2 and P3 of three groups were fed diets with different levels of crude protein at 11.25%, 12.5% and 13.75% (low, medium and high) respectively, while the dietary energy levels remained unchanged. Choose ewes with the same body condition from 90 days of pregnancy to different protein diets during delivery, and feed the same diets during lactation. New-born lambs were left to suckle their dams freely for the first three days and were kept with their dams till weaning at 60 days of age. Dietary protein levels during late gestation showed no significant effect on the weight gain of ewes and their offspring in the late pregnancy (P > 0.05) but had significant effects on blood urea nitrogen (BUN), glucose (GLU), C-reactive protein (CRPL3) and ammonia nitrogen (NH3L) before parturition, and on triglyceride (TG) in lactating ewes. Dietary protein levels during late gestation had significant effects on birth height, body length, chest depth, chest circumference, straight crown hip length and curved crown hip length of lambs (P < 0.05) as well as on weaning body length, chest circumference, head width and head length (P < 0.05). The results showed that although different dietary protein levels during late gestation have no significant effects on growth performance of ewes, singleton, twins and triplets, it affects lambs body shape and ewes metabolism. Therefore, the optimum protein concentration for the growth of ewes and subsequent lambs in this experiment is 11.25%.