Adding distiller's grains and molasses on fermentation quality of rice straw silages

Ensilage is a simple and low-cost strategy to enable long term preservation and environmentally friendly utilization of agricultural by-products, such as straws and distiller's grains (DG) for ruminants. Effect of mixing different proportions of DG and rice straw (i.e. 0, 10, 20 or 30% of DG) with or without 5% molasses addition on fermentation and chemical variables of silages was evaluated. The study was conducted as a randomized blocks design in a 4 x 2 factorial arrangement, with three replications, using laboratory silos of 1L capacity (n= 24). Despite a significant interaction (P<0.01) between DG and molasses addition was observed for most variables, in general the increased addition of DG linearly decreased the pH value, acetic acid (AA), butyric acid (BA) and ammonia N concentration (P< 0.01), and increased the lactic acid (LA) concentration (P< 0.01). Exception was the propionic acid concentration which linearly decreased without molasses addition and linearly increased with molasses addition at increased proportion of DG (P< 0.01). In both silages with or without molasses the addition of DG increased the dry matter, water soluble carbohydrates and crude protein (P< 0.01), and decreased the NDF content (P< 0.01). Based on the perspective of maximum utilization of rice straw, the mixture of 10% of DG associated to 5% molasses at ensilage process is recommended.