本试验旨在研究日粮精粗比与泌乳奶牛咀嚼活动的关系。选择4头安装有永久性瘤胃瘘管的初产荷斯坦泌乳奶牛，按4×4拉丁方设计，研究精粗比约为30∶70的高低质粗料型日粮、30∶70的混合型高青贮日粮、50∶50的精粗料比例相当的日粮及65∶35的高精料日粮对奶牛干物质(dry mater，DM)、中性洗涤纤维(neutral detergent fiber，NDF)与物理有效NDF(physical effective NDF，peNDF)等营养物质进食量及采食与反刍等咀嚼活动的影响。结果表明：日粮精粗比显著(P<0.05)或极显著(P<0.01)影响奶牛DM、NDF和peNDF进食量；显著(P<0.05)或极显著(P<0.01)影响奶牛日采食时间和单位DM、NDF、peNDF进食量的采食时间及日采食次数、单次采食时间；显著(P<0.05)或极显著(P<0.01)影响除奶牛单次反刍时间和日反刍次数外的反刍活动参数；显著(P<0.05)或极显著(P<0.01)影响奶牛日咀嚼时间、单位DM、NDF、peNDF、ADF进食量咀嚼时间及单位DM、peNDF进食量咀嚼次数。由此可知，通过调节咀嚼活动，4种不同精粗比的日粮均能满足奶牛对peNDF的需要量，且能获得维持合适乳脂率和瘤胃pH的咀嚼时间。

The aim of the study was to investigate the relationship between the dietary concentrate-to-forage ratio and the chewing activity of the lactating dairy cows. Effects of dietary concentrate-to-forage ratio on the intake of nutrients (such as dry matter, neutral detergent fiber and physical effective neutral detergent fiber) and chewing activity (such as the eating activity and the ruminating activity) were evaluated using four primiparous Holstein cows with permanently ruminal cannula in a 4×4 Latin square design. Dietary concentrate-to-forage ratios were 30∶70, 30∶70, 50∶50 and 65∶35, respectively. The results showed that the dietary concentrate-to-forage ratio significantly (P<0.05 or P<0.01) affected the following: the intake of DM, NDF and peNDF; the feeding activities including daily feed time, single feed time, daily feed times and feed time per kg of nutrients (DM, NDF and peNDF) intake; the ruminating activities except single ruminating time and daily ruminating times of dairy cows; the chewing activities of daily chewing time, chewing time per kg of nutrients (DM, NDF, peNDF and ADF) intake and chewing times per kg of nutrients (DM and peNDF) intake of dairy cows. In conclusion, four diets with different concentrate-to-forage ratios could meet the requirements of peNDF and acquire the chewing time so as to maintain the appropriate milk fat percentage and rumen pH for the dairy cow by adjusting chewing activities.［Chinese Journal of Animal Nutrition, 2009，21(6):998-1005］