Most farmers experience heating of silage largely due to growth of yeast and mold. Good management, including proper compaction, reduces the heat. However, some crops, such as corn, heat more often than other crops.Yeasts & molds are fungi that grow well in the presence of oxygen. Yeasts initiate the heating of silage and molds usually follow. Certain molds produce harmful mycotoxins. Mycotoxins may compromise production and health of animals.