The 2022 crop is concerned about mycotoxins and mold


Here are the next steps producers can take to control mold in feed

Harvest shows that mycotoxin levels are above normal in many regions of the United States. (University of Illinois)

ELK RIVER, Minn. — Harvest shows that mycotoxin levels are above normal in many crop areas in the United States. So far, during the 2022 harvest season, we are seeing an increase in deoxynivalenol (vanitoxin) in the Eastern Corn Belt and surrounding areas. Other toxins, including zearalenone and fumonisin, are found in more localized parts of these same areas. Further south, aflatoxin and fumanisin levels have also increased this year.

What does this mean for producers who use or will use this grain?

Just remember that your best defense is knowledge. Collect information about what’s happening in your area. I recommend frequent sampling and analysis throughout the harvest season and periodically during feeding for toxins that could be a hazard to your business.

In general, if the amount in the grain is extremely high, it is often necessary to dilute and limit the grain to animals at risk. Other broad-spectrum actions may include feeding gut health supplements that support the immune system. In my experience, a combination of feeding, immune support, vaccinations along with a prevention plan for the future provides the most protection for cow health and production.

  1. Limit feeding the most vulnerable animals to higher risk ingredients. Based on test results and mycotoxin risk, closely monitor animals fed high-risk feed and manage feed formulation. Stressed animals, young and reproductive animals are most at risk. For ingredients that may be at risk, you can include separation and discarding of fines, use clean forages to reduce concentration, and stockpile silage after spoilage and before adding to the mixer.
  2. Support of the immune system. Once consumed, mycotoxins often trigger an immune response and suppress the cow’s ability to fight infection and disease. The digestive tract and intestines play an important role in reducing the entry of mycotoxins into the body. Gut health supplements such as yeast and antioxidants (Vitamin E, AOXTM, Selenium) can strengthen the immune system.
  3. Use an additive in the formulation. Feed additives can be an effective tool in managing the risks associated with the presence of mycotoxins. Peer-reviewed studies have shown that some substances can minimize mycotoxin exposure through binding or detoxification.
  4. Include in the diet organic acids that suppress yeast and mold. A three-acid blend of acetic, benzoic, and propionic acids can help control yeast populations and protect your rations from mold and mildew growth. This tactic benefits the forage in front of your cows by reducing nutrient loss due to yeast and mold growth and increasing cows’ dry matter intake during heat stress.
  5. Prevention can cost more than treatment. The most common route of exposure to mycotoxins is the consumption of contaminated feed, making crop quality a critical factor in the development of mycotoxicosis in animals. Prevention begins in the field, where mold is always present. It’s as simple as understanding your crop and its environment. What is the right soil nutrient profile for your plant? Is it possible to plant a disease-resistant hybrid? What management practices, such as tillage or tillage and crop rotation, are implemented?

Although no animal diet can be guaranteed to be toxin-free, these basic principles can be applied to reduce the risk and exposure to mold and mycotoxins. Proactively working with your nutrition team by gathering knowledge and finding prevention and management strategies can be positive for cow health and feed cost.

A printout of the most common mycotoxins in dairy feed, along with management tips, can be found at

Management of mycotoxins in dairy feed

The most common mycotoxins are aflatoxins, deoxynivalenol (also known as DON or vomitoxin), zearalenone, and fumonisin. Use this chart when analyzing mold tests. Watch for key symptoms associated with each mycotoxin and note which foods may be the culprit.

Description of mycotoxins Meets Symptoms in animals

Highly toxic and cancer-causing mycotoxins that reduce productivity and overall animal welfare. Calves are most susceptible to aflatoxin.

  • Corn
  • Wheat
  • Cotton seed
  • Sorghum
  • Peanut
  • Peanut shell
  • Corn offal
  • Decreased milk production
  • Dry, scaly skin on the face
  • Liver damage
  • Hair loss
  • General appearance of poor health

Deoxynivalenol (DON) is relatively common in the northern half of the United States and in Canada. DON is one of the most immunosuppressive mycotoxins, causing increased risk from other stressors.

  • Corn
  • Wheat
  • Barley
  • Oats
  • Sorghum
  • Rye
  • Grain silos
  • Corn offal
  • Decreased production of milk and milk fat
  • High number of somatic cells
  • Decreased function of the scar
  • Damaged mucous membranes
  • Diarrhea

Also known as reproductive mycotoxins, zearalenone and related compounds are most harmful to the breeding herd.

  • Corn silage
  • High moisture corn
  • Barley
  • Sorghum
  • Irregular or absent estrus cycles
  • Decreased conception rate
  • Increased embryonic losses
  • Early reproductive maturity
  • Decreased fetal development
  • Lower viability of newborns

Fumonisins are common in the southern half of the U.S. Ruminants are generally less susceptible to fumonisins than monogastric species.

  • Grain
  • Corn
  • Corn offal
  • Corn silage
  • Some grain silages
  • Decreased feed intake
  • Decreased immune response
  • Decreased liver and kidney function

— Don Gisting, Chief Innovation Officer, Cargill Micro Nutrition The 2022 crop is concerned about mycotoxins and mold

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