Effects of maize meal and limestone on the fermentation profile and aerobic stability of smooth bromegrass (Bromus inermis Leyss) silage

Abstract Chemical‐compositional characteristics of crops are crucial factors affecting the fermentation profile and aerobic stability of silages. To evaluate the effects of starch content and buffering capacity, fresh smooth bromegrass was ensiled alone (control), with 9% maize meal ( MM ), or with a mixture of 9% maize meal and 1.5% limestone ( MX ) on a fresh matter basis in sealed plastic bags. After 1, 3, 14 and 56 days of ensiling, triplicate bags of each treatment were opened for chemical and microorganism analyses, and then the samples ensiled for 56 days were placed in polyethylene containers to evaluate their aerobic stability. During the early days of ensiling, the mixtures of maize meal and limestone favoured lactic acid bacteria growth, lactic acid production and decrease in pH values. After 56 days of ensiling, the MX ‐treated silages had significantly higher ( p < .05) lactic acid, ammonia‐N and buffering capacity compared with the silages treated with other additives. The aerobic stability of MM ‐treated silages was significantly lower ( p < .05) than that of the control silages, but the MX ‐treated silages showed higher ( p < .05) aerobic stability than the other groups. The changes of organic acids and pH in the MX ‐treated silages were also delayed, which inhibited the growth of aerobic bacteria and yeasts. These results indicate that maize meal improved the fermentation profile of smooth bromegrass silage but had a negative effect on its aerobic stability; however, limestone played important roles in both accelerating fermentation and the improvement of aerobic stability.