Biomass production and silage quality of ensiled BRS Capiaçu elephant grass at different regrowth ages and residue heights

The aim of this study was to determine the optimal combination of regrowth age and residue height of BRS Capiaçu elephant grass that yields the best balance between the dry mass production (DMP) of the harvested forage and silage quality. Four regrowth ages (75, 90, 105, and 120 days) and two residue heights (10 and 50 cm) were evaluated. The experimental design used a randomized complete block design with a 4 × 2 factorial scheme and 3 replicates. The regrowth age led to a linear increase in DMP. As regrowth age advanced, there were linear increases in the dry matter (DM) concentration, cell wall constituents, and fraction C (acid detergent insoluble nitrogen) of crude protein and reductions in the in vitro digestibility of DM and neutral detergent fiber (IVNDFD) in both the plant and its silage. Lower pH values were observed in silage made from plants harvested at 10 cm. No significant effects of the studied factors were found on the concentrations of organic acids in the silage, except for propionic acid. Management using a 105-day regrowth period and a 10-cm residue height resulted in a better balance between the dry mass production, fermentative profile and nutritional value of silage.