不同NFC/NDF比日粮对奶山羊瘤胃pH动态变化的影响

试验采用动态pH连续监测记录系统对瘤胃pH进行24h连续监测,旨在研究不同非纤维性碳水化合物/中性洗涤纤维比(NFC/NDF比)日粮对奶山羊瘤胃pH昼夜动态变化的影响。选用6只安装有永久性瘤胃瘘管的关中奶山羊作为试验动物,采用自身对照试验设计,分为4期,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:瘤胃pH随着日粮NFC/NDF比增加而显著降低(P<0.05),瘤胃pH<5.2、5.5、5.8、6.0的平均持续时间亦随日粮NFC/NDF比增加而延长,分别由Ⅰ期的0、0、2.42h/d和9.40h/d增加到Ⅳ期的0.33、7.50、17.06h/d和20.53h/d;瘤胃pH<5.5、5.8、6.0曲线面积亦逐步加大,分别由Ⅰ期的0、0.21和1.43(pH·h)增加到Ⅳ期的1.09、4.84和8.59(pH·h);而且瘤胃pH下降速率和下降幅度及最低值所持续的时间亦随日粮NFC/NDF比增加而增加。

Effects of Non-fiber Carbohydrate to Neutral Detergent Ratios on Ruminal pH Dynamics in Dairy Goats

Six Guanzhong dairy goats with permanent ruminal cannulae were used to determine the effects of four different ratios of NFC to NDF in diets on the ruminal pH dynamics.The NFC/NDF were1.02(Ⅰ),1.24(Ⅱ),1.63(Ⅲ) and 2.58(Ⅳ),respectively.In the present study ruminal pH were monitored continuously by continous ruminal pH measuring and recording system.The results showed that ①Ruminal pH values were decreased significantly with the increase of NFC / NDF.②with the increase of NFC/NDF,mean duration times under pH 5.2,5.5,5.8 and 6.0 were increased from 0,0,2.42 h and 9.40 h to 0.33 h,7.50 h,17.06 h and 20.53 h.Curve areas under 5.5,5.8 and 6.0 were increased from 0,0.21 and 1.43 to 1.09,4.84 and 8.59.The rate and degree of pH decline postfeeding and the duration of pH nadir were increased with increase of dietary NFC / NDF.