低蛋白氨基酸平衡日粮对产奶牛的生产性能和粪尿氮含量的影响

Effect of low protein amino acid balanced diet on production performance and nitrogen content in feces and urine of lactating dairy cows

研究了低蛋白氨基酸平衡日粮对奶牛生产性能及氮排放的影响,探讨在不影响生产性能的前提下减少奶牛粪尿中氮的排放量。选择30头年龄、胎次、泌乳期和产奶量相近的荷斯坦奶牛,随机分为3组,每组10头,分别为对照组(饲喂基础日粮配方),试验Ⅰ组和Ⅱ组在基础日粮配方上分别减少0.80%和1.66%的氮(粗蛋白质),分别添加过瘤胃赖氨酸(RPLys)24.6 g/d+过瘤胃蛋氨酸(RPMet)10.4 g/d、RPLys 25.7 g/d+RPMet 9.4 g/d平衡日粮中的氨基酸。预饲期7 d,正试期42 d。测定产奶量、乳成分、表观消化率及粪尿氮含量。结果显示:与对照组相比,试验Ⅰ、Ⅱ组的采食量、4%的标准奶产量、乳成分和日粮表观消化率无显著变化(P>0.05);试验Ⅰ组和试验Ⅱ组的粪尿氮排放量较对照组分别降低了7.67%和15.19%(P<0.05);奶牛经济效益与对照组相比,每天分别增加了0.45元/头和3.17元/头。上述结果表明,在氨基酸平衡的基础上适当降低日粮蛋白不影响奶牛生产性能,同时还减轻氮排泄对环境的污染,为低蛋白氨基酸平衡日粮的实际应用提供依据。

In order to control emissions of nitrogen from feces and urine of dairy cows and still maintain their normal production performance,the effects of low-protein amino acid balanced diets on performance and nitrogen emissions of dairy cows were studies in this experiment.Thirty Holstein cows were randomly chosen and divided into 3 groups(n=10):the control group(fed with basal diet),and GroupsⅠandⅡwere fed with a diet by reducing 0.80%and 1.66%of nitrogen(crude protein)on the basis of the diet for the control group,respectively,but by adding RPLys24.6 g/d+RPMet 10.4 g/d and RPLys 25.7 g/d+RPMet 9.4 g/d to balance the amino acids in the diet.The trial lasted for 49 days:7 days for feeding adaptation and 42 days for the formal experimental during which the milk production,milk composition,apparent digestibility and nitrogen contents in the feces and urine of the cows were measured.The results showed that,compared with the control group,there were no significant differences in feed intake,4%standard milk yield and milk composition,and apparent digestibility of the diet between GroupsⅠandⅡ(P>0.05);but the total nitrogen excretion was decreased by 7.67%and 15.19%(P<0.05),respectively,and the economic benefits were increased by 0.45 and 3.17 RMB per head and per day,respectively.The above results indicated that appropriate reduction of nitrogen levels in the diet on the basis of amino acid balance did not affect the performance of dairy cows,but helped alleviate environmental pollution caused by nitrogen excretion,which might provide reference for practical application of low-protein amino acid balanced diets.