本实验研究NCG对奶牛泌乳性能的影响，选取20头年龄、胎次、泌乳状况基本相同的荷斯坦奶牛随机分成两组，分别饲喂在基础日粮中添加0（实验组）和20g/d/头（实验组）的NCG（N-氨甲酰谷氨酸）日粮。实验结果表明，日粮中添加NCG可使奶牛日产奶量提高0.7kg（(P<0.05），可使每头奶牛一个泌乳期增加经济利润1088.85元；乳脂率降低显著(P<0.05），乳蛋白率显著升高(P<0.05）。提示NCG可以通过尿素循环间接影响奶牛泌乳量及乳成分。

20 Chinese Holstein cows of basically the same condition at age and lactation were selected, randomly divided into 2 groups of 10 cows. This experiment was assigned to 2 dietary treatments: control group (0%) and NCG group (20 g/d) to study the effects of N-carbonyl glutamic acid added into dairy diet on yield of dairy cattle. The results indicated that the milk production and milk protein rate of the NCG group was higher than that of the control group; the fat in every milk samples was lower. The economic return of the NCG group was higher than that of the control group. It could be concluded that NCG could indirectly affect milk yield and components of milk by urea cycle.