泌乳奶牛氨基酸营养

给产奶牛补加过瘤胃蛋白质如鱼粉和保护的大豆饼粕对提高乳蛋白含量和乳产量并不是最好的方法。奶牛在乳蛋白合成上也需要多肽或短肽,它们在乳腺中可能作为前体直接参与乳蛋白合成。奶牛通过注射补充混合氨基酸(必需AA+ 非必需AA)或只注射必需AA 都可提高奶产量并明显提高乳蛋白含量和产量,但乳糖含量有所下降。进而,向奶牛日粮中添加经保护处理的氨基酸,如赖氨酸、蛋氨酸、苯丙氨酸和组氨酸,也能明显提高产奶量和乳蛋白含量。

Amino Acid Nutrition of Lactating Dairy Cow

The provision of undegradable protein(fishmeal or protected soya)to the diet of lactating dairy cows is not the best method to raise the protein content in milk and the milk yield.Dairy cow needs peptides of some AA that will be used as precursors for milk casein biosynthesis.It is probably involvement of blood peptides and/or protein as precursors of mammary gland protein synthesis.The infusions of mixtures of all the AA in the ratios and only essential AA caused modest response in milk yield and significant increase in milk protein concentration,but reduction in milk lactose content. The supplement of protected essential AA to the diet,such as Lys,Met,Phe and His can result in a significant response in milk protein content too.