Investigations into the role of specific micro-organisms in the aerobic deterioration of maize silage

Abstract

SummaryTwo experiments were undertaken with maize silage, which had been sterilized by subjecting it to a 6 Mrad dose of γ radiation, inoculated with micro-organisms implicated in the aerobic deterioration of silage and subsequently exposed to air. The inocula employed comprised mixed strains of yeasts, bacilli and lactic acid bacteria and combinations of these. The changes which accompanied aerobic deterioration were observed. The major losses of fermentation acids, ethanol, ammonia and dry matter, and increases in total nitrogen and temperature were associated with inocula in which yeasts were represented. Similar changes of a lower magnitude were also observed in silage treated with inocula containing bacteria only, although these were not always accompanied by the growth of these organisms or loss of dry matter. However, when employed in mixed inocula with yeasts, the bacteria proliferated and tended in some instances to increase losses further, suggesting an association between the groups of micro-organisms in the aerobic deterioration process. Losses were also sustained in sterile silage which received no inoculum and the possible reasons for this are discussed.