本试验旨在研究不同比例的玉米压块秸秆和羊草组成的日粮对奶牛瘤胃发酵、日粮消化率以及生产性能的影响。试验选用4头体重为（550±25） kg的装有永久性瘤胃瘘管的泌乳奶牛，采用4×4拉丁方设计，4个日粮处理精料组成相同，粗料组合分别为：100%玉米秸（100% CS）、60%的玉米秸+40%羊草（60% CS+40% CW）、40%玉米秸+60%羊草（40% CS+60% CW）和100%羊草（100% CW）。试验期共60 d。结果表明：4个日粮处理间奶牛瘤胃pH差异不显著（P＞0.05），60% CS+40% CW组和40% CS+60% CW组pH变化较平缓。日粮处理间氨态氮（NH3-N）浓度、微生物蛋白质（MCP）产量以及各种挥发性脂肪酸（VFA）浓度差异均不显著（P＞0.05）。随着羊草比例的增加，乙酸/丙酸值逐渐减小。60% CS+40% CW组日粮中性洗涤纤维（NDF）消化率比100% CS组有提高的趋势（P=0.10），其他营养成分消化率各组间差异不显著（P＞0.05）。4个日粮处理条件对奶牛生产性能的影响不显著（P＞0.05）。由此可见，粗饲料由不同比例压块玉米秸秆和羊草组成的日粮对奶牛瘤胃发酵和生产性能的影响差异均不显著，均可提供正常的瘤胃发酵和泌乳的营养需要，能达到较高的乳脂率。60% CS+40% CW组有提高日粮NDF消化率的趋势。

This trial was conducted to study the effects of different proportion of corn straw and Chinese wildrye on rumen fermentation, dietary digestibility and performance of cows. Four lactating Holstein cows with an average body weight of (550±25) kg with ruminal cannula were used according to a 4×4 Latin square design.The four dietary groups consisted of the same concentrates but with different roughages, and the four kinds of roughages were composed of 100% corn straw (100% CS), 60% corn straw+40% Chinese wildrye (60% CS+40% CW), 40% corn straw+60% Chinese wildrye (40% CS+60% CW) and 100% Chinese wildrye (100% CW), respectively. The trial lasted for 60 d. The results showed that there was no significant difference among the four groups in the rumen pH (P＞0.05), and the pH value of the 60% CS+40% CW group and 40% CS+60% CW group was more stable. The differences of the production of NH3-N, MCP and VFA among the four groups were also not significant (P＞0.05). As the ratio of Chinese wildrye increased, the acetate-to-propionate ratio was decreased. Compared with the 100% corn straw treatment, the 60% CS+40% CW group had the tendency to increase dietary NDF digestibility (P=0.10). There was no significant difference in the digestibility of other dietary nutrients and the performance of dairy cows among the four groups (P＞0.05). It was concluded that the four groups with different proportion of compacted corn straw and Chinese wildrye could satisty the nutrition requirement in normal rumen fermentation and lactation of dairy cows with high milk fat percentage, but there was no significant difference among the four groups in rumen fermentation and performance. The 60% CS+40% CW group had the tendency to increase the dietary NDF digestibility. ［Chinese Journal of Animal Nutrition, 2010，22（2）:474-480］