Impact of days post-burning and lime as an additive to reduce fermentative losses of burned sugarcane silages

Abstract

The objectives of our study were: 1) to investigate the effects of burning and the time elapsed between burning and ensiling on characteristics of sugarcane silages, and 2) to evaluate the effects of lime on fermentation and aerobic stability of in natura and burned sugarcane silages. In trial I, silages were prepared from burned sugarcane that remained in the field for varying number of days post-burning (1, 5, 10, 15, 20, 25, and 30 d). In trial II, the characteristics of burned and in natura sugarcane silages treated with various concentrations of lime (0, 5, 10, 15, and 20 g/kg of sugarcane, on an as-is fresh matter basis) were compared. In trial I, 10-d post-burning, sugarcane crop displayed great degrees brix (18.3°Bx) and sucrose (677.3 g/kg of sugarcane broth) values. The yeast population in sugarcane crop 1-d post-burning (4.47 cfu/g of fresh forage) was lesser than that 25-d post-burning (7.11 cfu/g of fresh forage). After the silos were opened, all silages showed low pH. The silage from 1-d post-burning had the least dry matter (DM) recovery (637.5 g/kg of DM). The greatest DM recovery was found in the silage prepared 15-d post-burning (740.0 g/kg). Silage from 20-d post-burning displayed the greatest aerobic stability (36.7 h); however, in general, all silages had low aerobic stability (<40 h). In trial II, both the in natura and burned silages had reduced fiber content due to lime addition. Considering the overall mean, burned silages produced 47 g acetic acid/kg of DM against 25.6 g/kg of DM in in natura silages. Lime was more effective in increasing the production of acetic acid in in natura silages, but only when applied at great concentrations (15 and 20 g/kg). DM recovery of in natura silages decreased with increased addition of lime, whereas the opposite effect was observed for burned silages. In natura and burned silages treated with lime at 15 and 20 g/kg had greater aerobic stability (>8 d) than those treated with lesser quantities of lime. Considering the approach in which this study was carried out, a period of 10-15 days is ideal for ensilage of burned sugarcane prior to the silage quality significantly drops. Lime may be used as an additive for both in natura and burned silages since in greater levels (15 and 20 g/kg).