Institute of Dairy Science, MoE Key Laboratory of Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, Hangzhou 310058, P.R. China.
Institute of Dairy Science, MoE Key Laboratory of Molecular Animal Nutrition, College of Animal Sciences, Zhejiang University, Hangzhou 310058, P.R. China.
J Dairy Sci. 2018 Dec;101(12):10985-10990. doi: 10.3168/jds.2018-15162. Epub 2018 Sep 27.
The present study was conducted to investigate the effect of N-carbamoylglutamate (NCG) on milk production and composition in mid-lactating Holstein dairy cows. Sixty multiparous cows with a mean body weight of 669 kg (standard deviation = 71) and 176 days in milk (standard deviation = 55) were blocked based on parity and milk production and randomly assigned into 4 treatments, a basal diet supplemented with 0, 10, 20, or 40 g of NCG/d per cow. Milk yield and composition were recorded weekly, whereas dry matter intake and plasma variables were determined every 2 wk. The results showed that the addition of NCG had no effect on the dry matter intake and milk yield of the cows. Milk fat content and yield increased linearly with NCG addition. The contents of milk protein and total solid also increased linearly in the cows fed NCG, whereas the yield of protein was not affected by the treatments. Conversely, dietary addition of NCG increased the plasma nitric oxide content in a quadratic manner. Moreover, addition of NCG linearly increased the plasma Arg content. Overall, the results indicate that dietary NCG addition increased the milk protein and fat contents, which improved the milk quality of lactating dairy cows.
本研究旨在探讨 N- 氨甲酰谷氨酸（NCG）对泌乳中期荷斯坦奶牛产奶性能和乳成分的影响。选择 60 头经产奶牛，平均体重 669kg（标准差=71），泌乳天数 176 天（标准差=55），根据胎次和产奶量进行分组，随机分为 4 个处理组，每组 15 头奶牛，对照组饲喂基础日粮，试验组分别在基础日粮中添加 0、10、20 或 40g/d 的 NCG。每周记录产奶量和乳成分，每 2 周测定干物质采食量和血浆变量。结果表明，添加 NCG 对奶牛的干物质采食量和产奶量没有影响。随着 NCG 添加量的增加，乳脂含量和产量呈线性增加。奶牛饲喂 NCG 后，乳蛋白和总固体含量也呈线性增加，而蛋白产量不受处理的影响。相反，日粮添加 NCG 以二次方式增加了血浆中一氧化氮的含量。此外，添加 NCG 还使血浆 Arg 含量呈线性增加。总之，结果表明，日粮中添加 NCG 提高了乳蛋白和乳脂含量，改善了泌乳奶牛的乳品质。
