Four hybrid forage sorghums with different tannin concentrations and moisture in the stem were ensiled in laboratory silos made of PVC tubes. The silos were opened 1 (P2), 7 (P3), 14 (P4), 28 (P5) e 56 (P6) days after ensiling, in order to evaluate fermentation patterns and others parameters. Twenty-four treatments were used, with four repetitions each: 4 hybrids (T1=moist stem/low tannin, T2=not moist stem/low tannin, T3=not moist stem/high tannin, T4= moist stem/high tannin) and with six periods, since the forages before ensiling were also studied. Dry matter content (DM), crude protein (CP), ammonia nitrogen (N-NH3) and tannin were determined. Data were evaluated by analysis of variance, with mean separation achieved using Tukey statistical test. All sorghums had N-NH3 production during the fermentation, which was lower in high tannin sorghums. The N-NH3 concentrations were lower than those in the literature. High tannin sorghums had higher dry matter contents.
Silage; sorghum; tannin; nitrogenous compound