| The experiment was conducted to investigate the effect of different additives on fermentation quality and aerobic stability of mixed silages of tall fescue and common vetch, and the proper rate of adding different additives on the fermentation quality and aerobic stability of mixed silages of tall fescue and common vetch silages were determined, in the further, the effect of proper rate of adding different additives on the fermentation quality and aerobic stability were estimated on60th days or45th during aerobic stages, the pH, dry matter lactic acid and water soluble carbohydrate were analyzed, and the proper adding rate was selected. the dynamic changes in fermentation were in further studied with the selected adding rate with different additives treatments during aerobic stages.1The fermentation quality of mixed silages of Tall Fescueand Common VetchThis study was carried out to evaluate fermentation quality of mixed silages of tall fescue and common vetch. The treatments were as follows:CK (100%tall fescue),85%tall fescue+15%common vetch (C15),70%tall fescue+30%common vetch (C30) and55%tall fescue+45%common vetch (C45). The laboratory silos were opened on7,24,45and60days after ensiling in triplicate and the fermentation quality was analyzed. Based on the results, the contents of the lactic acid and water soluble carbohydrate decreased and the values of pH and NH3-N/TN increased significantly(P<0.05) with increasing rate of common vetch in mixed silages. At the end of ensiling, the values of pH(4.72) and NH3-N/TN (96.19g kg-1TN) of C45were higher significantly (P<0.05) than other treatments, the contents of the dry matter, lactic acid and the water soluble carbohydrate were lower significantly (P<0.05) than other treatments, and the crude protein was not significant (P>0.05) difference compared with C30. However, all treatments showed little amounts of butyric acid and propionic acid during ensiling. In conclusion from the present study, that mixing70%tall fescue and30%common vetch are recommended for fermentation quality and utilization efficacy2Study of effects of additives on common vetch and tall fescue fermentation quality2.1Effect of Adding Cornzyme and Lactic Acid Bacteria on Fermentation Quality of Mixed Silages of Tall Fescue and Common Vetch in TibetThe aim of this study is to evaluate the effects of adding enzyme, LAB and their combinations on the fermentation qualities and residual Water soluble carbohydrates of mixed silages of Common Vetch and Tall fescue during ensiling. The treatments were as follows:control (C), enzyme (E), LAB, enzyme+LAB(E+LAB), these silos were opened on7,24and60days after ensiling and the fermentation quality was analyzed. Compared to the control silage, separate adding of enzyme or LAB were efficient in improving the fermentation quality of mixed silages, and the combination addition further increased the LA content and decreased the pH value. The E combination treatments including the E alone showed higher Acetic acid and Total Volatile fatty acids content as compared with the control and LAB treated silage. The propionic and butyric acid were hardly found in all silages during ensiling. The combination treated silages showed highest WSC content and lowest AN/TN through the whole ensiling. These indicated that the E and LAB were of synergistic effects on the fermentation quality. From the above results it was suggested that the combination addition of enzyme and LAB is better for improving the fermentation quality of mixed silages of Common Vetch and Tall fescue in this experiment.2.2Effect of Adding molasses and Lactic Acid Bacteria on Fermentation Quality of Mixed Silages of Tall Fescue and Common Vetch in TibetThe aim of this study is to evaluate the effects of adding molasses or/and LAB on the fermentation qualities of mixed silages of Common Vetch and Tall fescue during ensiling. The treatments were as follows:control (C), molasses (M), LAB, molasses+LAB(M+LAB), these silos were opened on1,24,45and60days after ensiling and the fermentation quality was analyzed. Compared to the control silage, adding molasses+LAB were efficient in improving the fermentation quality of mixed silages, and the combination addition further increased the LA content and decreased the pH value. Silage adding with molasses or/and LAB showed lower AN/TN and higher WSC content as compared with the control and LAB treated silage, but molasses alone addition silages showed no significant difference with combining addition silages. From the above results it was suggested that separate addition of molasses and the combination addition of molasses and LAB addition is better for improving the fermentation quality of mixed silages of Common Vetch and Tall fescue in this experiment.3Study of effects of additives on common vetch and tall fescue fermentation quality and aerobic stability3.1Effect of Adding propionic acid on Fermentation Quality of Mixed Silages of Tall Fescue and Common Vetch in TibetThe aim of this study is to evaluate the effects of adding different levels of propionic acid (0.3%,0.4%,0.5%) on fermentation quality and aerobic stability of mixed silages of Common Vetch and Tall fescue during the ensiling. The pH value of all silages was gradually increased after exposed to air, and significantly increased before6days, Silage adding with propionic acid addition significantly lower than control. Compared with the control, the addition of propionic acid decreased the AN/TN and increased the WSC content of the silage, inhibited the activity of aerobic microbial and the decline of lactic acid content during the aerobic phase, the value of over0.4%additions significantly higher than control. These results indicated that adding over0.4%propionic acid effectively inhibited the activity of aerobic bacteria, improved the silage aerobic stability, reducing the aerobic deterioration of silage during exposure days.3.2Effect of Adding ethanol on Fermentation Quality of Mixed Silages of Tall Fescue and Common Vetch in TibetThe aim of this study is to evaluate the effects of adding different levels of ethanol (1.5%,2.5%,3.5%) on fermentation quality and aerobic stability of mixed silages of Common Vetch and Tall fescue during ensiling. Compared with the control, the addition of ethanol decreased the AN/TN and increased the WSC content of the silage, inhibited the activity of aerobic microbial and the decline of lactic acid content during the aerobic phase. However, lactic acid content in silages was gradually reduced with the increase of ethanol addition. Silages adding with3.5%ethanol showed significantly (p<0.05) lower lactic acid content other groups. From the above results, it was suggested that adding1.5%ethanol not only effectively inhibited the activity of aerobic bacteria, but also improved the silage aerobic stability during exposure days. 3.3Effect of Adding sorbic acid on Fermentation Quality of Mixed Silages of Tall Fescue and Common Vetch in TibetThe effect of adding different levels of sorbic acid (0.10%,0.15%,0.20%) on fermentation quality and aerobic stability of mixed silages of Common Vetch and Tall fescue was assessed. The pH value of all silages was gradually increased after exposed to air, and significantly increased from4to6days, Silage adding with0.15%and sorbic acid addition did not greatly change and significantly lower than control and0.1%S.the sorbic acid inhibited the decline rate of lactic acid and the residual LA content in creased with the amount of sorbic acid addition increasing, the value of over0.15%additions significantly higher than control. The sorbic acid addition decreased AN/TN and In creased WSC. Moreover there was significant difference among all treatments. These results indicated that adding over0.15%sorbic acid effectively inhibited the activity of aerobic bacteria, improved the silage aerobic stability, reducing the aerobic deterioration of silage during exposure days. |
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