| In order to enlarge the resource in Tibet, hulless barley straw was conserved as total mixed ration (TMR) silage by combing with whole crop oat, alfalfa and concentrate. This experiment was carried out to study the effects of oats being replaced by barely straw ratio on fermentation quality and aerobic stability of TMR silages, to choose the proper replaced ratio and to make the formula of dairy cattle in middle milk stage in Tibet. Furthermore, three silage additives were added to TMR silages, and to study those effects on fermentation quality and aerobic stability, and supply theoretical evidences for the development of silage additives in Tibet.1. Fermentation quality and aerobic stability of TMR silages containing hulless barely straw at different percent of dry matterAbstract:The TMR silages prepared with barely straw, whole-plant oats, alfalfa, and concentrate, on a DM basis, with oats being replaced by barely straw at 0%(C),12%(L), 22%(M),32%(H). Triplicate silos were opened after 45 days for fermentation quality and chemical analyses, and other silos were exposed to the air for 12 days aerobic stability analysis. All silages were of good quality with high lactic acid contents, low ammonia/total nitrogen and butyric acid content. The M and H treatments showed higher (P< 0.05) pH value and lower (P< 0.05) lactic acid contents, while L treatment showed no significant (P > 0.05) change, compared with control. During the aerobic period, the pH value and ammonia/total nitrogen of deteriorated TMR silage with hulless barely straw at 22% percent of dry matter increased significantly (P< 0.05), and the lactic acid and water soluble carbohydrate concentration decreased significantly (P< 0.05). The pH of other TMR silages show no significantly change in the aerobic exposure, and L treatment show the acetic acid content and lowest counts of aerobic bacteria and yeast and lowest ammonia/total nitrogen, and the pH keep at about 4.40, improved aerobic stability. In conclusion, this study demonstrated that the proportion of barely straw to be incorporated into TMR silages should be 12% of the DM. The treatment didn’t decreased fermentation quality significantly, but enhanced aerobic stability.2. Effects of adding molasses and acetic acid on fermentation quality and aerobic stability of TMR silage in TibetAbstract:This study was to evaluate the effects of acetic acid or/and molasses on the quality of TMR. Treatments included as follow: control without additive, with acetic acid (0.3% fresh matter basis), molasses (3% fresh matter basis), or acetic acid+molasses. Triplicate silos were opened after 45 days for fermentation quality determination, and other silos were exposed to the air for 12 days for aerobic stability analysis. All silages were of good quality with high lactic acid contents, almost no propionic acid, low ammonia/total nitrogen and butyric acid content. During aerobic exposure, the contents of lactic acid, acetic acid and water soluble carbohydrate of all ammonia/total nitrogen silages tend to decrease, the pH value of control and molasses increase significantly to 5.70 and 6.50 on day 12, and the ammonia/total nitrogen and counts of yeast were higher than acetic acid and acetic acid+molasses. However, acetic acid treatment showed lower (P< 0.05) ammonia/total nitrogen compared with control. Lactic acid content in acetic acid treatment and acetic acid+molasses silages increased during earlier stage of aerobic exposure, and then slowly changed. Counts of undesirable microorganism and yeast in acetic acid treatment keep low levels during aerobic exposure, and the pH value remained at about 4.50 after 12 d of aerobic exposure. It is suggested that adding 0.3% acetic acid not only maintained well fermentation quality, but also effectively improved the aerobic stability of TMR.3. Effects of adding lactic acid bacteria and acetic acid on fermentation quality and aerobic stability of TMR silage in TibetAbstract:The objective of this experiment was to study the effects of acetic acid or/and lactic acid bacteria on the quality of TMR silage. Treatments included as follow:control without additive, with acetic acid (0.3% fresh matter basis), lactic acid bacteria (6 log cfu g-1 fresh matter basis), or acetic acid+ lactic acid bacteria. Triplicate silos were opened after 45 days for fermentation quality determination, and other silos were exposed to the air for 12 days aerobic stability analysis. All silages with almost propionic acid, low ammonia/total nitrogen and butyric acid content. L and AL treatments significant (P< 0.05) increased lactic acid concentration and significant (P< 0.05) decreased pH value. control silage deteriorated with pH value significantly (P< 0.05) increased to 5.7 after 12 days of aerobic exposure. Other additive treatments showed no significant (P> 0.05) change in pH value and lactic acid content. A and AL treatments showed greater (P< 0.05) acetic acid content and lower (P< 0.05) yeast counts, enhanced aerobic stability. In conclusion, it is suggested that adding 6 log cfu g-1 lactic acid bacteria and 0.3% acetic acid not only improved the fermentation quality, but also effectively enhanced the aerobic stability of TMR. |
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