过瘤胃保护氨基酸提高奶牛乳蛋白转化效率的研究

为提高奶牛乳蛋白含量和饲料蛋白质用于产奶的转化效率,选择体况、胎次、泌乳期相近的中国荷斯坦奶牛27头,采用L9（34）正交试验设计,研究奶牛不同小肠可消化蛋白（IDCP）供应水平日粮添加过瘤胃保护氨基酸（RPAA）对乳蛋白率含量和IDCP转化为乳蛋白效率的影响。结果表明,IDCP按《中国奶牛饲养标准》（2004）推荐需要量92%水平供应,组合添加过瘤胃保护赖氨酸（RPlys）32 g/d＋过瘤胃保护蛋氨酸（RPmet）8 g/d,日粮干物质中NDF水平控制在37%～41%,可有效提高泌乳前期奶牛乳蛋白含量与IDCP用于泌乳的转化效率。

Study on Rumen-protected Amino Acids to Improve the Conversion Efficiency of Milk Protein

An experiment was conducted to promote the protein percentage in milk and conversion efficiency of feed protein to be used for lactation was performed.Twenty seven hatching lactating Chinese Holstein cattle at close calving parity,same milk stage and good body condition were given different levels of intestinal digestible crude protein(IDCP) and ruminal protected amino acids(RPAA) in a L9(34) orthogonal experimental design.The results indicate that provision of available IDCP accounting for 92% of the requirement recommended by China Feeding Standard Of Dairy Cattle(2004 edition) combining with the supplement of ruminal protected lysine(RPlys) 32 g/d + ruminal protected methionine(RPmet) 8 g/d,and neutral detergent fiber(NDF) of 37% to 41% in diet dry matter could effectively increase the protein percentage in milk and the conversion efficiency of protein used for milk production in lactation dairy cows.