目的 为探讨合理的日粮精粗比，提高奶牛的产奶性能。 方法 试验选用48头中国荷斯坦奶牛，年龄3~5岁，随机分为4组，每组12头，分别饲喂精粗比为50∶50、60∶40、65∶35和70∶30的饲粮，编号为A、B、C、D组，预试验7 d，正式试验周期30 d，检测各组试验奶牛产奶性能及牛乳品质。 结果 随着精料比例的提高，荷斯坦奶牛的产奶性能和牛奶品质均明显提高；高精粗比饲粮组（C、D组）的奶牛饲喂30 d后，日产奶量分别达到21.51、22.65 kg,而料肉比显著降低；牛乳中乳蛋白率和乳总固体物显著升高，C、D组分别是3.17%、11.87%及3.19%、11.97%，两组的牛奶品质比较接近。 结论 在一定范围内，提高日粮中精料的添加比例可有效提高奶牛的产奶性能，改善牛乳品质，综合成本因素，且在本试验条件下，饲喂精粗比为65∶35的日粮效果最佳。

Objectives A reasonable concentrate-roughage ratio of diet was studied to improve the milk production performance of dairy cows. Methods 48 Holstein cows from China aged 3-5 years were randomly divided into 4 groups, with 12 cows in each group. They were fed with concentrate-to-roughage ratios of diet as 50∶50, 60∶40, 65∶35, and 70∶30, and numbered as the group A, group B, group C, and group D. The preliminary experiment lasted for 7 days, and the formal experiment period was 30 days. The milk production performance and milk quality of dairy cows in each group were investigated. Results The milk performance and milk quality of dairy cows were significantly improved with the increase of the concentrate-to-roughage ratios of diet. After feeding cows in the group with high concentrate-to-roughage ratios of diet (group C and group D) for 30 days, their daily milk production reached 21.51 and 22.65 kg, while the conversion rate of feed decreased significantly. The rate of milk protein and total milk solid in group C and group D increased significantly, with 3.17% and 11.87%, and 3.19% and 11.97%, respectively. The milk quality of the two groups is relatively similar. Conclusions Increasing the concentrate-to-roughage ratios of diet within a certain range can effectively increase the milk production performance of dairy cows, improve the milk quality. Feeding a diet with a concentrate-to-roughage ratio of 65∶35 has the best effect taking into account cost factors and under the conditions of current experiment.