Effects of ethanol, molasses and Lactobacillus plantarum on fermentation characteristics and aerobic stability of total mixed ration silages

Abstract This study was conducted to evaluate the effects of Lactobacillus plantarum , molasses and/or ethanol on fermentation quality and aerobic stability of total mixed ration ( TMR ) silage, which is widely used in dairy cow diets at mid‐to‐late lactation in Tibet. TMR was treated with ethanol (E), molasses (M), Lactobacillus plantarum (L), ethanol+molasses ( EM ), ethanol+ Lactobacillus plantarum ( EL ) plus control. After 45 d of ensiling, inoculant significantly ( P < 0·05) increased lactic acid ( LA ) concentration and decreased pH , ammonia nitrogen ( AN ) concentration, and aerobic bacterial and yeast counts, compared to control. After the first 3 d of aerobic exposure, LA for silages without ethanol started to decrease, while LA for E silages almost remained unchanged till the end of the aerobic exposure period. The pH in TMR silages without ethanol gradually increased, while that for E and EL remained about 4·60 and 4·00, respectively, and EL showed the lowest pH among six silages over the course of aerobic exposure. Aerobic bacterial counts in control, M and EM silages were significantly higher ( P < 0·05) than those in E, L and EL , and yeast counts in E and EL silages were significantly lower ( P < 0·05) than those in other silages after 9 d of aerobic exposure. The results suggest that inoculation with L. plantarum was more effective in altering fermentation characteristics than adding molasses, while ethanol showed a potential to protect TMR silages from pH increase and delayed the growth of aerobic bacteria and yeast either alone or in combination with L. plantarum .