不同蛋白水平饲粮对荷斯坦公犊牛生长性能、氮消化代谢和血清指标的影响

Effects of diets with different protein level on growth performance, nitrogen digestion and metabolism and serum indexes of Holstein male calves

研究旨在探讨不同粗蛋白水平饲粮对断奶前后犊牛生长性能、氮消化代谢和血清指标的影响。选取30头20日龄、平均体重为(48.33±4.75)kg荷斯坦公犊牛,随机分为2组,每组15头。饲喂粗蛋白水平分别为19%(L)和22%(H)的两种饲粮。试验期70 d,其中预试期10 d,正试期60 d。每天测定采食量,每隔30 d测量体重和体尺;在犊牛60日龄和90日龄时采用全收粪尿法进行消化代谢试验;在30、60日龄和90日龄时饲喂前颈静脉采血。结果表明:①试验全期两处理组间的平均日增重(ADG)、日均采食量(ADFI)和料重比(F/G)差异均不显著(P>0.05)。90日龄,L组的体斜长显著大于H组(P<0.05);②试验全期两处理组间粪氮、沉积氮、氮表观消化率和氮沉积率差异均不显著(P>0.05),90日龄H组的摄入氮、尿氮和消化氮显著高于L组(P<0.05);③试验全期两处理组间的血清总蛋白(TP)、葡萄糖(GLU)、白蛋白(ALB)和球蛋白(GLB)差异均不显著(P>0.05),90日龄H组的尿素氮(BUN)、谷丙转氨酶(ALT)和谷草转氨酶(AST)均显著高于L组(P<0.05)。综上所述,相比19%粗蛋白水平饲粮,22%粗蛋白水平饲粮对犊牛的生长性能有不利影响,但对氮沉积率和氮表观消化率没有影响,易导致犊牛腹泻。

The purpose of this study was to evaluate the effects of diets with different protein level on growth performance,nitrogen digestion and metabolism and serum indexes of calves before and after weaning.Thirty Holstein calves aged 20 days with an average weight of (48.33±4.75) kg were randomly divided into two groups with 15 calves in each group.Feeding crude protein level is 19%(L) and 22%(H) respectively.The test period was 70 d,of which adaptation period was 10 d and formal period was 60 d.Feed intake was recorded everyday,and body weight and body ruler was measured every 30 d. Digestion and metabolism experiments were carried out at 60 d and 90 d using total feces and urine collection method.At the age of 30,60 days and 90 days,blood was sampled from the anterior jugular vein.The results showed that:① There were no significant differences in average daily gain (ADG),average daily feed intake (ADFI) and feed weight ratio (F/G) between the two treatment groups during the whole period of the experiment (P>0.05).At the age of 90 days,the body oblique length of group L was significantly larger than that of group H (P<0.05).② There was no significant difference in fecal nitrogen,deposition nitrogen,apparent nitrogen digestibility and nitrogen deposition rate between the two treatment groups(P>0.05),the intake nitrogen,urine nitrogen and digestive nitrogen in the 90-day-old H group were significantly higher than those in the L group (P<0.05).③ There was no significant difference in serum total protein (TP),glucose (GLU),albumin (ALB) and globulin (GLB) between the two treatment groups in the whole period of the experiment (P> 0.05),and the urea nitrogen (BUN),glutamic pyruvic transaminase (ALT) and glutamic oxaloacetic transaminase (AST) in the 90-day-old H group were significantly higher than those in the L group (P< 0.05).To sum up,compared with the 19% crude protein level diet,the 22% crude protein level diet has a negative impact on the growth performance of calves,there is no effect on nitrogen deposition rate and nitrogen apparent digestibility,easily causing calf diarrhea.