Effects of molds and their toxins on livestock performance: a western Canadian perspective

Molds (fungi) develop from spores that are found ubiquitously in the environment. Mold growth on grain under field conditions or during storage can occur at moisture levels above 16% and at temperatures above freezing. The growth of molds on grain can affect the nutritional quality of grain in several ways. First, they decrease the nutritional value of the commodity as they consume fats, protein and carbohydrates that are present in the grain. Thus these nutrients are no longer available to the animal. Secondly, some species of mold are able to produce highly toxic compounds called mycotoxins. These toxins can adversely affect animal health and production and can cause harmful effects to humans if transmitted into foods. The combined presence of mold and mycotoxins may cause decreased feed intake, decreased feed efficiency, decreased rate of gain, and increased risk of infection as well as reproductive problems. Toxins that are produced in the field that are of greatest concern are deoxynivalenol (DON or vomitoxin) and T-2 toxin while ochratoxin A and citrinin are the toxins of greatest concern in stored grain. The latter toxins are potent carcinogens and cause irreversible kidney damage. Economic losses to producers and health hazards caused by moldy grain can be minimized, if not eliminated by following sound management practices.