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Mycotoxins in Beef Cattle

What are mycotoxins?

Mycotoxins are harmful, naturally occurring substances produced by certain molds (fungi). These fungi commonly grow on feedstuffs and tend to multiply during adverse weather conditions. More than 500 mycotoxins have been identified to date, and this number is steadily increasing.

Mycotoxin risk for beef cattle

Ruminant animals are generally considered to be less susceptible to mycosis than monogastrics. This is thought to be because rumen flora degrade and inactivate in-feed mycotoxins. However, several mycotoxins resist rumen breakdown, and ruminants must often deal with a myriad of challenges because their diet often contains both concentrates and forages.

Where do mycotoxins come from?

The presence of mycotoxins in corn and in forages such as grass, hays and silage poses one of the greatest threats to beef cattle. Even fresh grass can be contaminated with several mycotoxins. These typically include fungal endophytes that produce mycotoxins, which protect the plant in some way, such as ergovaline and lolitrem B, as well as Fusarium mycotoxins, such as zearalenone or deoxynivalenol (DON).

The range of mycotoxins

Mycotoxins rarely occur in isolation. It is not uncommon to find multiple mycotoxins in finished feed, which allows for interactions between them, thereby leading to synergistic or additional effects. For more information on specific types of mycotoxins and related complications, visit

Signs of mycotoxins in beef cattle

The signs may vary depending on the specific type of mycotoxin, the dose ingested and the period of exposure, but they can include:

  • Immunosuppression
  • Decreased feed intake
  • Weight loss
  • Mouth ulcers
  • Impaired rumen function
  • Liver damage
  • Lameness
  • Diarrhea
  • Reduced lactation
  • Lower conception rates
  • Abortions
  • Premature births
  • Weak testicular development
  • Low sperm count

Preventing and managing mycotoxins in beef cattle

Reducing exposure to these harmful substances is key. Detection, prevention and mitigation are critical for an effective mycotoxin management strategy.

Regular analysis of feedstuffs can help uncover potential hidden threats from mycotoxins. It is worth noting that a highly contaminated sample does not mean that the entire crop is bad. Similarly, a “clean” sample does not guarantee that all of your feed is mycotoxin-free.

Proper mycotoxin management is essential in order to avoid unpredictable losses and maintain herd performance.

The Alltech 37+® mycotoxin analysis test can help to provide a realistic picture of feed contaminants, which can speed up diagnosis, determine effective remediation and help producers form a more effective mycotoxin control plan.