Effect of additive on fermentation quality of mixed silages of oat(Avena sativa)and common vetch(Vicia sativa)in Tibet

This experiment evaluated the effects of adding lactic acid bacteria,potassium sorbate and molasses on the fermentation quality of oat and common vetch(7∶3)mixed silages.The additive treatments were as follows:(1)control(no addition),(2)lactic acid bacteria(L),(3)potassium sorbate addition at 0.15%(S),(4)molasses addition at 3%(M).These silos were opened on 30,45 and 60days after ensiling and the fermentation quality was analyzed.Addition of L,M and S were efficient in improving the fermentation quality of mixed silages compared with the control.There were significantly(P0.05)higher lactic acid content,and lactic acid/acetic acid values in the M and L addition as compared with control and S addition,while the pH values,acetic acid,total volatile fatty acid content and ammonia nitrogen/total nitrogen values of these two silages were significantly(P0.05)lower than other two groups.M addition was slightly better than L addition for improving the fermentation quality of mixed silages.S addition greatly increased(P0.05)lactic acid content and lactic acid/acetic acid values,and significantly(P0.05)reduced the acetic acid,butyric acid content and ammonia nitrogen/total nitrogen values as compared with the control,however there were no significant(P0.05)differences between control and S-addition silages in pH values or propionic acid content.In conclusion,the improvement in fermentation quality with additives ranked as follows:MLS.