Managing Mycotoxins on the Farm

Mycotoxins are poisons produced by mold. While mold presence does not always indicate mycotoxin contamination, it does increase the likelihood of mycotoxin contamination in feedstuffs.

We’re seeing increasing cases of mycotoxin contamination on farms. It can be confusing for producers because their feedstuffs appear fine and harvest conditions did not suggest excessive mold formation. But many conditions can cause mycotoxin contamination. This includes drought conditions and excessive rainfall, hail damage, and improper feed storage and feeding conditions.


Cattle fed contaminated feedstuffs may exhibit a variety of physical symptoms. Common side effects include reduced milk production, increased disease rates and reproduction challenges. Other symptoms can include reduced feed intake, poor hair coat and diarrhea.

Diagnoses can be difficult because many of these symptoms are also symptoms of other herd-health issues. We recommend including products in the ration to support gut health and immune function. In these cases, products like our newly-formulated KuroCal™ FarmPack are a good option to help suppress the impact of mycotoxin-contaminated feeds.

Common Mycotoxins

If testing detects the presence of one mycotoxin, the chance of other types of mycotoxin contamination increases. The three most commonly detected mycotoxins include aflatoxin, deoxynivalenol (DON) and zearalenone. Aflatoxin is the most concerning mycotoxin because it is both commonly found and carcinogenic. The FDA regulates aflatoxin levels in milk. They can’t exceed 0.5 ppb.

Mycotoxin poisoning symptoms and tolerance levels for the three most commonly found mycotoxins are summarized in Table 1 below.


Preventing high levels of mycotoxin contamination can be accomplished through proper harvest and feed storage.

Limiting feed exposure to oxygen is the best way to prevent mycotoxin formation. It’s important that feeds are packed and stored properly, and that bunks are kept clean. If possible, avoid feeding moldy feedstuffs. If this is unavoidable, consider adding a product like KuroCal FarmPack to help suppress the stress associated with feeding poor-quality feedstuffs.