About Mycotoxins

Mycotoxins are toxic substances produced by naturally occurring moulds in crops and feed materials.  They can be produced pre-harvest 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 weather conditions and pest damage during crop growth or poor storage of harvested grains.

Even small amounts of mould can produce significant amounts of mycotoxins if the conditions are right.  There does not need to be visible mould growth for mycotoxins to be present.


Mycotoxins are produced by moulds.  Different mould species grow in different conditions, so the predominant mould species present is likely to change depending on geography.

Cooler more temperature regions such as northern Europe will likely see a greater occurrence of Fusarium moulds. These are primarily responsible for production of mycotoxins such as Deoxynivalenol, Zearalenone, and Fumonisins.  They are also able to produce other trichothecene toxins such as T2 toxin, HT2 toxin, and Diacetoxyscirpenol.

Warmer and more humid regions such as southern Europe, Africa, and South East Asia are more likely to be affected by Aspergillus mould species.  These are primarily responsible for producing Aflatoxins and Ochratoxins.

Mycotoxin production in the field can be caused by:

  • Adverse weather conditions inclulding extremes of temperature and rainfall.
  • Crop disease and weakness.
  • Insect and parasite damage.

Mycotoxins may be produced after harvest due to:

  • Inadequate drying of grains or straw.
  • Insufficient sealing of silage clamps or bales.


Symptoms of mycotoxin exposure can vary greatly between different animal species, with some being more susceptible to specific toxins than others.

Click below more detailed information about mycotoxin exposure in different species.

Reduced Performance and Milk Production
Poor Growth Rate and Immunity
Poor Growth Rate and Fertility

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