Intermediate sorghum silages with different tannin concentrations and steam moisture content .1.. Ammonia nitrogen, pH and dry matter losses

Four intermediate sorghum hybrids with different tannin concentrations and stem moisture and their silages were evaluated. Sorghum hybrids were designated, based on treatments, as: H1 - moist stem, low tannin hybrid; H2 - dry stem, low tannin; H3 - moist stem, high tannin and H4 - dry stem, high tannin. They were classified in to six different periods: P1 - original material, P2 - silage opened after 24 hours, P3 - silage opened on seventh day, P4 - on 14(th) day, P5 on 28(th) day and P6 - at 56(th) day of fermentation. Sorghums were harvested and ensiled at 104 days of age when grains were in the mealy stage. The experimental design was completely randomized. Data were evaluated by analysis of variance, with mean separation achieved using the SNK Statistical Test and a 4 x 6 factorial scheme. The four hybrids showed a medium dry matter (DM) value at the time of ensilage of 27.6% and because of the low DM losses in P6 (5.52 - 8.28%), almost all the hybrids showed DM values similar to that of OM, except for H2, which had the highest value (30.27%). Crude protein values remained stable for all treatments with an average value of 8.96%. Values of ammonia nitrogen as percentage of total nitrogen in the silage were around 0.65 to 0.90% at P2 and from 1.27 to 2.53% at P6, with least percentages for H3 and H4. At P3, silage pH was already stable and it was 3.76 at P6. All silages were classified as very good quality.