Effect of applying different additives on the fermentation characteristics and aerobic stability of total mixed ration silage prepared with local feed resources in Tibet

This study was conducted to assess the effect of different additives on the fermentation characteristics, in vitro digestibility and aerobic stability of fermented total mixed ration (FTMR) prepared with local feed resources in Tibet, China. Additives added to FTMR were Lactobacillus buchneri (1 × 10⁶ cfu/g fresh weight (FW)), acetic acid (0.3% FW), propionic acid (0.4% FW), 1,2-propanediol and 1-propanol (0.5% FW). FTMR were opened after 90 days and subjected to a 14-d aerobic stability test. The results showed that L. buchneri, 1,2-propanediol and 1-propanol increased (P < 0.05) pH values and acetic acid concentrations and decreased (P < 0.05) lactic acid concentrations in FTMR. Adding acetic acid decreased (P < 0.05) lactic/acetic acid ratio. FTMR treated with propionic acid had higher (P < 0.05) lactic acid, propionic acid and DM recovery compared with the other treatments. Treating FTMR with acetic acid, 1,2-propanediol and 1-propanol decreased (P < 0.05) yeast counts. The in vitro potential gas production tended to be lower in L. buchneri-treated silage than other silages. During aerobic exposure, FTMR treated with propionic acid spoiled first, with marked pH increase and lactic acid decrease from days 9 to 14. Treatment with L. buchneri, acetic acid, 1,2-propanediol and 1-propanol markedly improved the aerobic stability, as indicated by nearly unchanged pH and lactic acid concentrations. The results suggest that L. buchneri, acetic acid, 1,2-propanediol and 1-propanol did not adversely affect the in vitro digestibility and could be effective additives for enhancing the aerobic stability of FTMR prepared on Tibetan plateau.