Effect of mechanical processing and storage length on whole-plant sorghum silage fermentation

Abstract

Due to their smaller size, sorghum grains often remain intact during ensiling, which can impair starch availability for fermentation and reduce their overall digestibility. Thus, this study aimed to evaluate the influence of the mechanical processing of the forage mass before ensiling, as well as the length of storage in whole plant sorghum silages. The experimental design was completely randomized, in a 2 × 3 factorial scheme, with two processing methods (non-processed or processed) and three storage lengths (35, 70, and 105 days). Two counter-rotating smooth rolls were used to smash the chopped forage, aiming to expose the starch matrix of the sorghum grains without altering the forage fraction particle size. Crude protein contents decreased while ammonia nitrogen increased for long storage length silages due to proteolysis. <italic>In vitro</italic> dry matter digestibility was lower for processed silage compared to non-processed silage. Storage length increased the percentage of particles retained on sieve 3 (> 4 mm), while decreased particles retained on sieve 2 (> 9mm) of the Penn state particle separator. The combination of processing method and storage length of whole-plant sorghum silages enhanced crude protein solubilization elucidating the effectiveness of these practices in promote starch availability.