Mycotoxins are produced by all types of molds, and affect animals in a wide variety of ways. Common molds and mycotoxins affecting ruminants include Fusarium (deoxynivalenol, zearalenone, T-2 toxin, fumonisin,  fusaric acid), Penicillium (PR toxin, patulin, penicillic acid, mycophenoloic acid) and Aspergillus (aflatoxin, ochratoxin).

Common effects of mycotoxins in ruminants include:

  • Variable intake
  • Scouring
  • Impaired immune function
  • Bloody feces
  • Lower leg/teat swelling
  • Muscle tremors
  • Poor performance
  • Inconsistent milk yield
  • Acidosis-type symptoms
  • Poor rumen function
  • Lethargy
  • Reduced fertility
  • Unsettled cows

Any feedstuff on the farm is a potential source of mycotoxins, and even apparently high-quality silage may contain a mycotoxin threat. Molds do not have to be visible for mycotoxins to be present. Testing is possible, but is relatively expensive and has limited effectiveness.

Risk assessment

Alltech offers this mycotoxin risk assessment you can use with your producers to assess their risk for mycotoxin problems.

Forages and feeds

  • Are you feeding high dry matter forages?
  • Is there any soil contamination of/in your forage?
  • Is there evidence of spoilage or heating in any feedstuffs?
  • Were there any unusual pre- or post-harvest weather conditions?
  • Has poor performance coincided with any dietary changes?

Herd health and performance

  • Has there been any inconsistency in milk yields?
  • Has there been an increase in disease incidence?
  • Are  your cows showing symptoms of acidosis?
  • Have you noticed any inconsistency in dung quality?
  • Any other unexplained concerns?

This practice tip courtesy of Alltech. For more information visit