A study of the chemical and microbial changesin whole-plant corn silage during exposureto air: effects of a biological additive andsealing technique

摘要

The objectives of this study withwhole-plant corn silage were to determinethe effects of a biological additive andsealing technique on yeast and moldpopulations; and to examine therelationship between the microbial andchemical changes in the silages duringexposure to air. Whole-plant corn washarvested at 80% milkline (36% DM), andensiled at a density of 35 lb of freshmatter/ft3. Half of the pre-ensiled foragewas treated with a biological additive (A)(Sil-All 4×4, Alltech, Inc.); the other halfof the pre-ensiled forage was the untreatedcontrol (C). Half of the silos in the A andC groups were sealed immediately afterfilling (S=sealed) and the other half of thesilos were sealed 48 hours after filling(DS=delayed seal). Treatments consistedof combinations of the two factors: additive(A and C) and sealing technique (S andDS). There were three, 5-gal capacity,laboratory silos per treatment. Silos wereopened after 150 days, and the chemicaland microbial compositions and aerobicstability of the silages determined. All foursilages were moderately stable duringexposure to air. The C, DS silage was thefirst to show a rise in temperature, whichoccurred after 65 hours. The two DSsilages were 48 hours less stable than theirS counterparts, and the two A silages were24 hours more stable than their Ccounterparts. Deterioration of the silagesduring exposure to air was accompanied byan increase in temperature and pH, adecrease in lactic acid content, and a rapidincrease in the lactate-assimilating yeastpopulation. Treatment with a biologicaladditive significantly improved aerobicstability, and delayed sealing reduced theaerobic stability of silages.