Influence of molasses additive and moisture level at ensiling on fermentative characteristics of Panicum maximum

Abstract

Silages made from directly cut or wilted Panicum maximum treated with or without molasses, were evaluated to determine fermentative characteristics. The grass was harvested at the boot stage of growth and the material of each treatment was ensiled in separate 1kg mini-silos. Compared to day 0 (control), silage pH dropped significantly at day 7 for molasses-treated silage regardless of initial moisture level. In the untreated silage a slightly lower pH was recorded for the unwilted silage. Molasses treatment resulted in a lower silage pH, higher lactic acid and lower acetic acid concentrations starting from day 7 throughout the fermentation period. Compared to prior wilted silages, lower (p < 0.05) pH, higher lactic acid and lower acetic acid concentrations were recorded for directly cut silages throughout the fermentation period. Molasses had no influence on the nitrogen (N) content of silage, but wilting resulted in a higher N content compared to unwilted silage in presence of molasses. Neither the influence of molasses nor the initial moisture level had a significant effect on ammonia nitrogen (NH₃-N) concentration on day 7, but an interaction between molasses addition and moisture level was evident on day 21 and 120. The level of ammonia nitrogen increased with fermentation time. The addition of molasses seemed to be beneficial to the fermentation process and resulted in well preserved silage, whereas the effect of initial moisture condition seems to have little significance.

Keywords: fermentation process, moisture level, molasses, Panicum maximum, silage

African Journal of Range & Forage Science 2007, 24(2): 97–102