不同蛋白质来源对早期断奶犊牛消化及血清生化指标的影响(一)

Effects of Different Protein Sources on Nutrient Digestibility and Serum Biochemical Parameters in Early-weaning Calves (I)

本文研究了不同蛋白质来源代乳品对早期断奶犊牛生长发育、常规营养物质消化率及部分血清代谢指标的影响。选取15头新生健康荷斯坦犊牛分为3组,分别饲喂乳蛋白和植物性蛋白质比例为80:20、50:50及20:80的代乳品,记为S20、S50及S80组。结果表明,S80组犊牛的总增重、平均日增重均低于其余2组,但统计上差异不显著(P>0.05);3组犊牛全程平均日增重分别为465、436和331 g/d。不同蛋白质来源对日粮常规营养素表观消化率无显著影响(P>0.05),但S80组略低。犊牛血清总蛋白(total protein,TP)含量在整个试验期内保持平稳,试验结束时S50组血清TP含量略高于其余2组,但差异不显著(P>0.05)。3组犊牛血清尿素氮(serum ureanitrogen,SUN)含量随日粮植物性蛋白质含量的升高而上升,试验结束时S80组显著高于S20组(P<0.05)。结果提示,利用植物性蛋白质代乳品饲喂早期断奶犊牛未对其增重产生不利影响,初生2～3周龄后的犊牛可以有效利用代乳品中的植物性蛋白质。

This study was designed to examine the effects of different dietary protein sources on growth performance, nutrient digestibility and serum biochemical parameters in early-weaning calves. Fifteen healthy new-born calves were randomly allotted to three experimental treatments and fed milk replacers which proteins were from milk and vegetable with different ratios of 80 ： 20, 50 ： 50 and 20 ： 80, respectively, labeled as S20, S50 and S80. The results showed that net gain and average daily gain （ADG） were lower in the S80 treatment than those in other treatments, however, the difference was not significant （P〉0.05）, the ADG of three treatments were 465, 436 and 331 g/d, respectively. There were no significant differences in the nutrient digestibility among three treatments （P〉0.05）, but the value in S80 treatment was a little lower. The serum total protein concentrations were not affected by dietary protein sources （P〉0.05）. Serum urea nitrogen（SUN） concentration, on the other hand, increased along with the increase of dietary protein sources, and the SUN concentration in S80 treatment was higher than that in S20 treatment significantly （P〈0.05）. It was concluded that there was no effect on growth performance by feeding vegetable protein milk replacer to early-weaning calves, and the calves at 2-3 week of age could use vegetable protein in milk replacer availably.