Aerobic stability of marandu grass silages submitted to different packing intensities during ensiling

This trial aimed to evaluate the aerobic stability of marandu grass silages submitted to different packing intensities. The forage was harvested at 60 days of regrowth. The following packing densities were evaluated: 100, 120, 140, and 160 kg DM/m(3). Silage chemical changes were determined 0, 3, and 6 days after air exposure and temperature recorded every 12 hours, during 156 hours after the buckets were placed in the climatic camera. Thermometers were inserted 10 cm into the silage mass. Data were analyzed following a repeated measures model in a complete randomized design with four replications. The silage with the highest density reached the maximum temperature value in a longer period, compared to the lowest density one, probably due to the highest stability. The pH values increased and ammoniacal nitrogen (N-NH3/TN) decreased during the air exposure phase. The NDIN (neutral detergent insoluble nitrogen) and B3 fractions decreased for the highest density silage, characterizing the participation of these fractions in the proteolysis process during the aerobic phase. The NDF (neutral detergent fiber) and ADF (acid detergent fiber) values increased during the aerobic exposure and the highest values were observed on the lowest density silages. The highest density silages showed higher true in vitro digestibility values compared to the other silages.