Qualitative parameters of pearl millet silage ammoniated with urea, at different compaction densities

Abstract

The objective of this work was to evaluate the effects of urea ammoniation of pearl millet silage, at different compaction densities, on chemical composition, losses in the ensilage process, fermentation profile, microbial population count, and aerobic stability. The experimental design was completely randomized, in a 2×4 factorial arrangement, with two compaction densities (600 and 800 kg m-3) and four urea levels (0, 2, 4, and 6% on a dry matter basis), with five replicates. For the aerobic stability assay, the experimental design was completely randomized, in a 2×4 factorial arrangement, with two times (0 and 72 hours) and four urea levels (0, 2, 4, and 6%, on dry matter basis), with five replicates. The urea levels interacted significantly with density as to the contents of organic matter, crude protein, neutral detergent insoluble protein, and as to dry matter recovery; and with exposure hours as to the contents of acid detergent fiber and lignin. Molds and yeasts were not observed in the ammoniated silages. The 800 kg m-3 density reduced losses in the fermentation process of pearl millet silage, and promoted better nutritive value than the compaction at 600 kg m-3. The use of urea does not reduce losses and does not improve the aerobic stability of silages; however, it controls mold growth after silage exposure to air.