Fermentative characteristics and aerobic stability of sorghum silages containing different tannin levels

Two experiments were conducted to evaluate effects of tannin levels in sorghum silages supplemented, or not, with polyethylene glycol (PEG) on silage chemical composition and fermentative characteristics as well as aerobic stability of silages supplemented with urea or concentrate. A completely randomized experimental design was applied in both experiments. Silages without PEG had higher CP levels and lower ammonia N concentration (81.8 g/kg DM and 55.3 g/kg N, respectively) as compared to silages with PEG (70.6 and 63.4, respectively). High-tannin sorghum levels were not able to maintain silage aerobic stability, probably due to their low concentrations in the silages.