The objective of this study was to research the influence of the sweet sorghum straw fermented by the Compound Microbial Agent on the milk yield and milk composition of the cows. The results indicated that sweet sorghum straw bio-feed fermented by the Compound Microbial Agent in bags could increase the feed intake (11.4%) and milk yield(14.2%) compared with the control group, it also has improved milk protein (14.03%) and butterfat rate (16.3%) ,and has reduced the somatic cell's number(5.15%) compared with the control group. The sweet sorghum straw fermented by the Compound Microbial Agent has reduced the milk-feed ratio (20.8%).It has improved the feed digestibility and utilization and reduced the costing.

The features and require of tradition hammer type straw knead machine, one kind new-type cutter of applying to straw knead machine was designed. The cutter of using zigzag longitudinal knife and dovetail zigzag cross knife, able to finish crops straw longitudinal knead and transverse cutting at once. Application of the new cutter, water and sugar lose significantly reduced in the knead straw, and working efficiency was reasonably well. Field experiments show that using this new tool knead moisture content 56% corn straw ,the moisture and sugar content of material were 50% and 10% respectively after kneading, productivity was1.9t, the length of straw material was 3~6mm.

The results indicated that the sweet sorghum straw bio-feed fermented in bags and cellar pits by the Compound Microbial Agent both could increase the content of the crude protein (CP) and reduce the content of the fibrinogen (FIB) compared with control group. The content of CP in bags fermented by Complex Microbial group has increased 71% and the content of FIB has reduced 8%. The CP content of cellar pits fermented by Complex Microbial group has increased 91% and the FIB content has reduced 24.5% . Compared with Silage corn stalks group , sweet sorghum straw bio-feed fermented by the Compound Microbial Agent could also improve the content of milk protein (14.03%,16.81%) and butterfat rate (16.3%, 92.98%) and reduce the somatic cell's number (5.15%,6.86%) in the milk. It has promoted the cows capacity to produce milk and also improved the quality and flavor of dairy product.