过瘤胃氨基酸对泌乳早期奶牛生产性能、乳成分和血液生化指标的影响

为研究日粮添加过瘤胃氨基酸对泌乳早期奶牛生产性能、乳成分、血液生化指标和经济效益的影响,选择96 头体况良好、健康的泌乳早期荷斯坦牛,泌乳天数为（65±15）天。采用单因素随机区组试验设计,按照年龄、胎次和产奶量相近的原则,将96 头奶牛随机分为对照组和试验组,每组48 头。对照组为基础日粮,试验组在对照组日粮的基础上添加过瘤胃蛋氨酸（RPMet）和过瘤胃赖氨酸（RPLys）,添加量分别为18 g/头·天和35 g/头·天。结果表明,与对照组相比,添加RPMet和RPLys显著提高产奶量（P=0.034）,对干物质采食量和饲料转化率无显著影响（P>0.050）;添加RPMet和RPLys显著降低乳尿素氮含量（P=0.015）,对乳脂率有增加的趋势（P=0.096）,对乳蛋白率、乳体细胞数、乳糖率和总固形物含量无显著影响（P>0.050）;添加RPMet和RPLys显著提高血清总蛋白（TP）、白蛋白（ALB）和血糖（GLU）含量,显著降低尿素氮（BUN）含量（P=0.049）,对谷丙转氨酶（ALT）、谷草转氨酶（AST）、球蛋白（GLOB）、碱性磷酸酶（ALP）、甘油三酯（TG）和总胆固醇（TC）含量无显著影响（P>0.050）;添加RPMet和RPLys可提高经济效益3.60 元/头·天。综上所述,日粮添加RPMet和RPLys可提高泌乳早期奶牛的产奶量,增加经济效益。

Effect of Rumen-protected Amino Acid on Production Performance,Milk Composition and Blood biochemical Parameter in Early Lactation Dairy Cows

This experiment was conducted to investigate the effect of rumen-protected amino acid on production performance,milk composition,blood biochemical parameter and economic benefits in early lactation dairy cows. 96 healthy Holstein cows in the early lactation period were selected, the average days in milk was (65±15) d.The experimentation was designed in single factor random block design and according to age,parity and milk yield similar,the 96 dairy cows were randomly divided into control group and experimental group,with 48 cows in each group.The control group was fed with basal diet and the experimental group was fed with basal diet supplemented with rumen-protected methionine (RPMet):18 g/head·d,rumen-protected lysine (RPLys) 35 g/head·d.The results showed as follows:Compared with the control group,dietary supplementation of RPMet and RPLys increased daily milk yield (P=0.034) and had no effect on dry matter intake and feed conversion rate (P>0.050);The dietary supplementation of RPMet and RPLys decreased milk urea nitrogen (P=0.015),tended to increase milk fat percentage (P=0.096),and had no effect on milk protein,somatic cell count,milk lactose rate and total solids content (P>0.050); The dietary supplementation of RPMet and RPLys increased TP,ALB and GLU content (P<0.050),decreased BUN content (P=0.049),and had no effect on ALT,AST,GLOB,ALP,TG and TC content (P>0.050).The dietary supplementation of RPMet and RPLys increased economic benefits by 3.60 yuan/(head·d).In conclusion, dietary supplementation of rumen-protected amino acid increased the milk production and economic benefits in early lactation dairy cows.