The chemical composition and in vitro dry matter digestibility (IVDMD) of corn and sorghum silages with and without microbial inoculants after several fermentation periods were evaluated in laboratory silos. A 6 x 2 x 3 factorial treatment combination (6 fermentation periods x 2 silages x 3 inoculants) was assayed in a completely randomized design to evaluate the dry matter (DM) and crude protein (CP) contents and a 4 x 2 x 3 factorial arrangement of treatments (4 fermentation periods x 2 silages x 3 inoculants) to evaluate the fiber constituents and IVDMD; in either case, there were three replications. Fermentation periods <FONT FACE=Symbol>´</FONT> silage <FONT FACE=Symbol>´</FONT> inoculant and inoculant <FONT FACE=Symbol>´</FONT> period interactions were observed for silage DM and CP silage contents, respectively. The neutral (NDF) and acid detergent fiber (ADF) had a triple interaction effect. Minimum NDF contents of 52.14 and 50.75% were observed in corn silage inoculated with Silobac and Maize-All inoculants, respectively. Corn silage with microbial inoculant showed lower cellulose content than the untreated silages. However, there was no inoculant effect on cellulose content in sorghum silage. The mean value of hemicelullose content was affected by silage, period and inoculant, higher value being observed in corn silage (29.8%) than in sorghum silage (28.4%). The IVDMD of corn silages treated with Silobac and Maize-All inoculants, increased quadratically with fermentation period, showing maximum values of 71.1 and 71.7% after 42.29 and 50.3 days of fermentation, respectively. IVDMD of sorghum silage was not influenced by fermentation period.
acid detergent fiber; cellulose; crude protein; dry matter; hemicelullose; neutral detergent fiber
