Chemical composition, aerobic stability, and fermentation pattern of white oat silage wilted with glyphosate

Abstract

White oat has good nutritional quality but is not an easy forage to ensile due to its high buffer capacity and moisture content at ensiling moment. Therefore, wilting is necessary to offset such negative aspects. However, this process demands skilled workforce and adequate machinery. In this way, chemical desiccation is a promising technology to reduce the steps needed for wilting. Thus, we aimed to evaluate the effects of glyphosate as a chemical desiccant on the nutritional quality, fermentation pattern, losses, and aerobic stability of wilted white oat (Avena sativa) silages. White oat sowing occurred in the first fortnight of May 2013. Desiccant application took place when oat reached milky-dough grain stage (96 days after planting). Glyphosate doses evaluated were 0, 500, 750, 1000, and 1250 mL ha?1. Three days after desiccation, all treatments were ensiled, and the silos were stored for 150 days. A completely randomized design was used, and all statistical procedures were performed by means of Bayesian Inference. No differences were found for lactic acid, but treated-silage pH linearly decreased. The lowest concentration of butyric acid (3.40 mg kg-1) was observed at 900.80 mL ha-1. For ammonia, the highest point (50 g kg-1) occurred at 916.51 mL ha-1. Aerobic stability was not influenced by treatments. Maximum dry matter recovery index (934 g kg-1) was observed at 864.20 mL ha-1 glyphosate. Wilted forage from treatments 500 mL ha-1, 750 mL ha-1, and 1000 mL ha-1 had greater dry matter content compared to control (320.1, 326, 301.3, and 270.7 g kg-1 respectively). Hemicellulose linearly decreased and crude protein linearly increased. The lowest concentrations of neutral detergent fiber (642.8 g kg-1) and neutral-detergent insoluble nitrogen (2.30 g kg-1) occurred at doses of 1141.32 mL ha-1 and 829.14 mL ha-1, respectively. In brief, for wilted white oat silage production, harvested at milky-dough grain stage, glyphosate application prior to ensiling up to 1000 mL ha-1 led to better conservation compared to non-treated silage.