饲喂各种日粮时牦牛瘤胃液体与瘤胃食糜的外流速度

The Dilution Rate of Rumen Fluid and Digesta in Yaks Receiving Various Diets

将７头体重１５０ｋｇ、带有瘤胃和十二指肠瘘管的牦牛在两个试验中喂以不同的日粮以研究其瘤胃液体与食糜外流速度。试验Ｉ，４头牛分两期喂给粗蛋白质为８％和１２％的等能（９．６ＭＪＭＥ／ｋｇ）日粮；试验Ⅱ，３头牛在一３ｘ３拉丁方设计中喂给精粗比７：３、５：５、３：７及以菜籽饼、豌豆、蚕豆为主要氮源的日粮。结果表明：饲喂精粗比３：７日粮时，瘤胃液体外流速度（３．９％／ｈ）比饲喂其它日粮时明显低，其它日粮间无明显差异，平均为１０．６％／ｈ；瘤胃食糜外流速度不受日粮的影响，平均为１３．３％；瘤胃液体积和十二指肠食糜流量均因干物质采食量的不同而受日粮的影响，干物质采食量高时二者相应也高。

yaks,weighing 150kg,fitted with rumen and duodenum cannulaes were used intwo experiments to study the dilution rate of rumen fluid and rumen disgesta.In trial I,4 ani-mals were used and given two isocaloric(9.6MJ ME/kg)dicts containing 8%and 12%crudeprotein. In trialⅡ,3 animals were used in a 3 x 3 latin square design,in which the ratio of di-etary concentrate:straw was designed to be 7:3,5:5,and 3:7 and the rapeseed,garden peaand broad bean were used as main nitrogen sources resp.All diets in trial Ⅱ contained 9.6MJME/kg and 12%crude protein. The clearance rate of rumen fluid with 3:7 diet(3.9%/h)waslower than that of other diets(10.6%/h),the dilution rate of rumen digesta was not effected bydiets,giving a mean value of 13.3%/h. Both rumen volume and flow rate of digesta reachingduodenum were effected by d iets due to the difference of dry matter intake,which was that thatahigher dry matter intake gave a higher rumen volume and higher digesta flow rate.