Jacques K, Harmon D L, Croom W J, Hagler W M
Kansas State University, Manhattan 66506.
J Dairy Sci. 1989 Feb;72(2):443-52. doi: 10.3168/jds.S0022-0302(89)79126-8.
Three experiments with ruminally fistulated cattle fed 12 times daily were conducted to study the role of saliva secretion in ruminal water balance when intake, diet, and feeding pattern were altered. Water balance data were determined from continuously infused Co-EDTA and pulse-dosed Cr-EDTA with saliva flow estimated by difference between water intake and ruminal outflow. Any net transruminal water flux would be included in the estimate of salivary flow. When the concentration of bluestem hay in the diet was increased from 50 to 90%, ruminal fluid volume, saliva secretion, water intake, dilution rate, and total ruminal outflow increased. At equal intake, the higher forage diet increased ruminal liquid volume, outflow, and saliva secretion but had no effect on dilution rate. Intake, but not forage concentration, affected ruminal pH when 50 and 90% hay diets were fed. Increasing feeding frequency of forage in a 65% bluestem hay diet from 4 to 12 times daily (the grain portion was fed 12 times daily) increased dilution and ruminal outflow; however, the latter was only significant with data from Cr-EDTA. Ruminal volatile fatty acids were not altered by feeding frequency of forage. Nycterohemeral patterns were seen in water intake, ruminal dilution rate, outflow, and salivary flow in both studies. Slaframine increased saliva flow by 29% and was accompanied by increased ruminal liquid volume, dilution rate, and outflow.
进行了三项针对每天饲喂12次的瘤胃瘘管牛的实验，以研究在改变摄入量、日粮和饲喂模式时唾液分泌在瘤胃水平衡中的作用。通过连续输注钴乙二胺四乙酸（Co-EDTA）和脉冲给药铬乙二胺四乙酸（Cr-EDTA）来确定水平衡数据，唾液流量通过水摄入量与瘤胃流出量之间的差值来估算。任何瘤胃净水通量都将包含在唾液流量的估算中。当日粮中须芒草干草的浓度从50%增加到90%时，瘤胃液体积、唾液分泌、水摄入量、稀释率和瘤胃总流出量均增加。在摄入量相等的情况下，较高的牧草日粮增加了瘤胃液体积、流出量和唾液分泌，但对稀释率没有影响。当饲喂50%和90%干草日粮时，摄入量而非牧草浓度会影响瘤胃pH值。在65%须芒草干草日粮中，将牧草的饲喂频率从每天4次增加到12次（谷物部分每天饲喂12次）会增加稀释率和瘤胃流出量；然而，后者仅在Cr-EDTA数据中显著。瘤胃挥发性脂肪酸不受牧草饲喂频率的影响。在两项研究中，水摄入量、瘤胃稀释率、流出量和唾液流量均呈现昼夜模式。毒扁豆碱使唾液流量增加了29%，同时伴随着瘤胃液体积、稀释率和流出量的增加。
