About Mycotoxins

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.
    Isakeit Corn


    Deoxynivalenol (DON)

    DON is produced by Fusarium species, which are the cause of Fusarium Head Blight (FHB).  Also known as vomitoxin, DON causes loss of appetite and sickness.  This results in lower feed intake and lower growth rates.  DON has also been shown to damage the epithelial lining of the gastro-intestinal tract, resulting in pathogens being able to pass through the lining into the bloodstream.


    Zearalenone is produced by Fusarium species and mimics oestrogen hormones.  It causes reproductive and fertility issues as a result including irregular heats, increased abortions, reduced milk yield, and reduced fertility.  Zearalenone is frequently found co-occurring with Deoxynivalenol.


    Fumonisins are also formed by Fusarium species.  They cause damage by disrupting sphingolipid production.  Exposure can cause immune supression, kidney and liver damage, and pulmonary oedema.


    Aflatoxins are produced by Aspergillus species and are more commonly found in warmer climates.  Aflatoxins are known carcinogens and their levels in feed and food are tightly regulated.  Metabolites of Aflatoxins are known to contaminate milk.  Symptoms of Aflatoxin exposure can include impaired rumen function, organ damage, and immune suppression.  Livestock are at increased risk of liver cancer and hepatitis.

    Ochratoxin A

    Ochratoxins may be produced by Aspergillus or Penicillium moulds.  They are known to interfere with DNA and RNA synthesis.  This can result in intestinal haemorrhaging, liver and kidney damage, immune suppression, and decreased growth and performance.


    Other members of the Trichothecene group (along with DON) include T2, HT2, and Diacetoxyscirpenol.  They all share a similar structure and mode of action, so can all result in similar symptoms to Deoxynivalenol.

    Follow us