不同发酵时间对全混合日粮的瘤胃降解特性以及小肠消化率的影响

试验旨在研究发酵0、3、7、15、30 d的全混合日粮(TMR)对瘤胃降解特性以及小肠消化率的影响。选用3头体重为550 kg左右、安装有永久性瘤胃瘘管的荷斯坦奶牛,采用尼龙袋法和三步体外法测定发酵全混合日粮(FTMR)的干物质(DM)、粗蛋白质(CP)、中性洗涤纤维(NDF)的瘤胃降解率以及瘤胃未降解蛋白(RUP)的小肠消化率。结果表明:随着发酵时间的延长,FTMR饲料的DM含量显著降低(P<0.05);随着发酵时间的延长,显著提高FTMR的DM、CP、NDF的瘤胃降解率(P<0.05)和CP、NDF的快速降解部分(P <0.05);同时发酵显著降低RUP的小肠消化率(P <0.05)。综上可知,全混合日粮提高了DM、CP和NDF在瘤胃中的瘤胃降解率,15、30 d的FTMR各营养成分的瘤胃降解性较好;RUP的小肠消化率随发酵时间的延长开始逐渐降低,7d之后降低最为明显。因此,应控制好TMR的发酵时间,以便更有效地利用饲料资源。

Study on Rumen Degradability Characteristics and Intestinal Digestibility of Fermented Total Mixed Ration

The objectives of this study were to research the effect of rumen degradability characteristics and intestinal digestibility of Fermented Total Mixed Ration. Three ruminally cannulated Holstein cows averaging 550 kg of body weighted were used to evaluate ruminal degradability of dry matter(DM), crude protein(CP) and neutral detergent fiber(NDF), intestinal digestibility of RUP using Nylon bag trial and three-step in vitro procedure. The results showed that the content of DM decreased significantly(P<0.05), others had no changes significantly compared with fresh TMR of 0 days. Along with the storage time, fermentation increased significantly dry matter, crude protein and neutral degradation fiber rumen disappearance and effective degradability of TMR(P<0.05), the DM effective degradation rate of 15 and 30 d was over 50%, the effective degradation rate of CP was over 55% and the effective degradation rate of NDF was approximately 30%; Fermentation increased significantly(P<0.05) fraction of immediately degraded of CP and NDF. But fermentation decreased significantly(P<0.05) intestinal digestibility of(rumen undegradable protein) RUP after 7 days. In conclusion, rumen nutrient disappearance and effective degradability increased(P<0.05), at the same times, causing the decrease of intestinal digestibility of rumen undegradable protein Therefore, Fermentation can keep the nutrition content of total mixed diet. Fermentation can increased rumen degradation rate of nutrients. Fermentation decreased intestinal digestibility of rumen undegradable protein. So, in order to more effectively use feed resources, avoiding waste, fermentation time should be control well in the use of FTMR.