Fermentation profile, microbial populations and aerobic stability of sorghum silages enriched with urea and Lactobacillus buchneri

We evaluated the microbial populations, fermentation profile, chemical composition, losses and aerobic stability of sorghum silages enriched with urea and Lactobacillus buchneri. Experiment design was set up as a completely randomised design with a 4 x 4 factorial arrangement consisting of four treatments (SS - sorghum silage without additive; SSI - sorghum silage with L. buchneri (10(5) cfu/g fresh matter); SSU - sorghum silage with urea (% DM); and SSUI - sorghum silage with urea and inoculant) and four opening times (15, 30, 60, and 110 days), with four replicates. The silage pH was influenced (P < 0.01) by the treatments, with the highest values found in SSI and SSU. Lactic acid contents decreased in SSI and SSUI, while acetic acid levels in those silages increased, consequently reducing the ethanol content (P < 0.01). The lowest yeast counts were obtained in SSI and SSUI. There was an effect for aerobic stability (P < 0.05) in which higher aerobic stability was observed to SSUI (87.3 h) compared to SS (61.0 h) and SSU (62.3 h). SSI did not differ between the other silages. The inoculant L. buchneri as associated with urea promoted positive effects on both fermentation and aerobic stability.