Silage fermentation and in Vitro degradation of monosaccharide constituents of wheat harvested at two stages of maturity

Wheat plants (Triticum aestivum) were harvested at the bloom and soft-dough stages and ensiled in laboratory silos, and the effect of stage of maturity on the recovery of soluble and cell wall components and on the in vitro digestibility of monosaccharide residues was examined. A total of 8-9% neutral detergent fiber (NDF) monosaccharides residues was solubilized and partly utilized during ensilage. Glucose and galactose were the most fermentable sugars among the ND soluble monosaccharides. Fructose was equally fermented in both silages, but the higher recovery of reducing sugars in the soft-dough silage as compared with the bloom silage (44.1 vs 26.8) indicates the possible participation of starch in the fermentation process of the former. Generally, the silages were less digestible than the source materials, but the difference was larger in the bloom treatment. Thus, a gap of 8.1 percentage units in total NDF monosaccharide digestibility (D) between the source materials was reduced to 5.5 units between the silages. The decline in the D values of the monosaccharide residues of the whole plant following ensilage was 11.5 and 6.0 percentage units for the bloom and soft-dough stages, respectively. The D of total monosaccharide residues of whole plant material was equal within the source materials but was 5.3 percentage units higher in the soft-dough silage than in the bloom one. Digestibility measurement at the monosaccharide level of source materials and silages offers a sharp tool for determining the optimal stage for harvesting wheat for silage. © 1995 American Chemical Society.