中文摘要：

试验旨在探讨日粮不同非纤维性碳水化合物/中性洗涤纤维比（NFC/NDF）对奶山羊瘤胃发酵参数的影响。选择6只安装有永久性瘤胃瘘管的关中奶山羊作为试验动物,采用自身对照试验法,共分为4组（分4期进行）,每期10d,依次饲喂NFC/NDF比分别为1.02（Ⅰ期）、1.24（Ⅱ期）、1.63（Ⅲ期）、2.58（Ⅳ期）的4种日粮。结果表明,随着日粮NFC/NDF比的提高瘤胃pH值降低,瘤胃pH值下降速率和下降幅度及pH值低于5.2、5.5、5.8、6.0的持续时间随之加快、延长;瘤胃丙酸、丁酸及总挥发性脂肪酸（TVFA）含量随日粮NFC/NDF比提高呈增加趋势,而乙酸含量及乙酸/丙酸则呈降低趋势;血浆乙酸、丙酸、丁酸及TVFA均呈增加趋势。当日粮NFC/NDF比达2.58时,瘤胃pH值在5.2～5.5之间持续时间每日达7h以上,此时瘤胃乳酸含量较低,血浆及瘤胃TVFA含量显著提高（P〈0.05）。结果表明,随着日粮NFC/NDF比的提高,使瘤胃逐渐处于酸性环境,改变了瘤胃发酵模式;瘤胃pH值的下降主要源于瘤胃TVFA增多,而非乳酸;当日粮NFC/NDF比为2.58时,奶山羊发生亚急性瘤胃酸中毒。

英文摘要：

To explore the effects of different dietary NFC/NDF ratios on ruminal fermentation parameters,6 Guanzhong dairy goats with permanent rumen cannula were divided into 4 groups （4 trial periods） and each period lasted for 10 d according to self-contrast experiment design.The goats were fed diets with different NFC/NDF ratios,which were 1.02 （periodⅠ）,1.24 （periodⅡ）,1.63 （periodⅢ） and 2.58 （periodⅣ）,respectively.The results showed that with the increase of dietary NFC/NDF ratios,ruminal pH decreased,at the same time, the rate and degree of pH decline and duration time for pH lower than 5.2, 5.5,5.8 and 6.0 were increased.Ruminal propionate,butyrate and TVFA content tended to increase,while ruminal acetate content and A/P ratio tended to decrease.Plasma acetate, propionate,butyrate and TVFA content tended to increase.When NFC/NDF ratio was 2.58,duration time of ruminal pH between 5.2 and 5.5 could last for more than 7 h per day.In this case,ruminal lactate content remained at a low level,blood and ruminal TVFA content increased significantly （P0.05）.The results indicated rumen fermentation pattern was changed with the increase of dietary NFC/NDF ratios which caused acid environment in rumen;the accumulation of TVFA was the main reason for pH decrease but not lactate itself;when NFC/NDF ratio was 2.58,SARA occurred in dairy goats.