A Little Fresh Air: Fungal Toxins and Silage

Silage, whether cereal based or formed from other feedstuffs, is a nutrient dense, high moisture commodity that provides an excellent substrate for the growth of molds and subsequent synthesis of mycotoxins. The primary control for the latter is the low availability of oxygen for these obligate aerobes in a milieu that is thought of as being anaerobic. The problem for commercial dairies is that silage is not totally anaerobic; some infiltration of air creates micro-environments with adequate oxygen to support growth of common molds. Ultimately, mycotoxin risk in silage is just a matter of a little fresh air! The task of the farmer is to strive for best initial quality in silage preparation and then use best management of the commodity and its storage facility to reduce the risks of de novo mycotoxin formation. However, mycotoxin contamination of silage is the rule, not the exception, and producers need to understand that those risks exist and take actions appropriate to control or minimize damage in their herds.