Abstract: We utilized equipment of macrofauna open-type with respiration and calorimetric function to research effect of active dry yeast and cellulose enzymes on the concentration of rumen VFA and emission of methane in Grassland Red cattle. Four Grassland Red cattle with eight months,similar body condition were selected. We used 4×4 latin square method to complete this experiment. Group Ⅰ was fed the basal diet as the control group,group Ⅱ added 200 mg/kg active dry yeast in the basal diet,group Ⅲ added 190 mg/kg cellulose enzymes in the basal diet,group Ⅳ added 200 mg/kg active dry yeast and 190 mg/kg cellulose enzyme at the same time in the basal diet. The test was divided into four periods and every period included 37 days. The results showed that after adding active dry yeast in the diet, it had an obvious effect on concentration of propionic acid and total VFA (P<0.05).The concentration of total VFA and propionic acid in groups Ⅱ and Ⅳ had significant effect than that in groupsⅠand Ⅲ(P<0.05). Active dry yeast obviously restained the production of methane from Red Grassland cattle (P<0.05), emission of methane from group Ⅱ was 9.84% and lower than groupⅠ. The effect of cellulose enzymes on the concentration of rumen VFA and methane emission had no obviously difference (P>0.05). Therefore, active dry yeast could improve rumen fermentation, increase concentration of propionic acid, reduce emission of methane and energy loss from Grassland Red cattle.

Key words: active dry yeast; cellulose enzymes; Grassland Red cattle; rumen fermentation; volatile fatty acid (VFA); methane