Mycotoxins are toxic substances produced by naturally occurring moulds in crops and feed materials. Mycotoxins can be produced in the field or post-harvest during storage.
Mycotoxins are produced by moulds as a stress response. Often this stress occurs in the form of extreme weather conditions during crop growth or poor storage of harvested grains.
There does not need to be visible mould growth for mycotoxins to occur. Even small amounts of mould can produce significant amounts of mycotoxins if the conditions are right.
Common mycotoxins include Deoxynivalenol, Zearalenone, and the Fumonisins, which are all primarily produced by Fusarium moulds.
Other mycotoxins such as the Aflatoxins and Ochratoxin are commonly produced during storage by Aspergillus and Penicillium moulds.
Symptoms of mycotoxins in livestock vary depending on the species, toxin, and level of exposure. Subclinical mycotoxicosis can be difficult to diagnose without precise measurements of feed materials.
Mycotoxin production in the field can be caused by:
- Adverse weather conditions including extremes of temperature and rainfall.
- Crop disease.
- Insect and parasite damage.
Mycotoxins can occur during storage due to:
- Inadequate drying of grains or straw.
- Insufficient sealing of silage clamps or bales.