饲粮蛋白质水平对舍饲育肥牦牛生长性能、养分表观消化率及血清生化指标的影响OA北大核心CSTPCD

The purpose of the study was to investigate the effects of different crude protein levels on the growth performance,nutrient apparent digestibility and serum biochemical indexes of house-feeding intensive fattening yaks fed in cold season.In this study,30 male yaks with good body condition and weight of(180.00±11.67)kg were randomly divided into three groups,with 10 replicates in each group and one yak in each replicate.Three crude protein levels were designed for total mixed diets(TMR),which were 12.5％(Group Ⅰ),15.5％(Group Ⅱ),and 18.5％(Group Ⅲ).The pre-test period was 30 days,and the formal test period was 90 days.The results showed that the total weight gain and average daily weight gain of yaks in Group Ⅰ and Group Ⅱ were significantly higher than those in Group Ⅲ(P＜0.05).The feed to weight ratio of yaks in Group m was significantly higher than that in Group Ⅰ and Group Ⅱ(P＜0.05).The apparent digestibility of crude ash in Group Ⅱ and Group Ⅲ was significantly higher than that in Group Ⅰ(P＜0.05).The activity of alanine aminotransferase(ALT)in yak serum of Group Ⅲ was significantly higher than that in Group Ⅱ(P＜0.05).The content of urea nitrogen(BUN)in Group Ⅲ was significantly higher than that in Group Ⅰ and Group Ⅱ(P＜0.05).The study indicates that the fattening effect of medium protein level diet in the yak fattening process is better,and the recommended protein level of yak diet in the cold season is 15.5％.