The Role of Microbes in Ensiling

Ensiling is the microbial processing of forage, based on the fermentation of plant sap that acidifies the silage to pH < 5. This acidity threshold prevents microbial activity that could otherwise produce inhibitory, toxic, malodorous or otherwise undesired metabolites. Anaerobic conditions are key to silage production and storage in silos because aerobic exposure would change the microbiota to counterproductive metabolism. This review outlines the principal microbial groups involved in the open ensiling process and discusses some additive effects with externally added compounds that have been used in this industry to enhance anaerobiosis, lactic acid fermentation, preservation, and safe storage. The ensiling process and the type of forage in the silage may impact methanogenesis in ruminants, and additional effects on ruminal digestion have also been reported.