Mitigating mycotoxin risk: 6 ways to avoid equine aflatoxin poisoning

Aflatoxin, a type of mycotoxin, has been making headlines recently due to a grain recall situation. This got me thinking: while the livestock world is generally well-versed in mycotoxin management strategies, the equine world is likely less familiar with mycotoxins overall.

As the name suggests, mycotoxins are toxic compounds, produced in nature by certain types of mold and fungi. More than 500 types of mycotoxins have been identified to date, and multiple varieties are commonly found in animal feedstuffs, especially when environmental conditions prove favorable; warmer temperatures and higher moisture levels are often key contributors.

Horses may be exposed to mycotoxins through the consumption of infected pasture grasses, moldy forages or contaminated grains; even bedding can be impacted. While you may be able to see the molds that produce mycotoxins on contaminated feedstuffs, mycotoxins themselves are not visible to the naked eye, making them even more difficult to destroy. So, what can you do?

Aflatoxicosis: Signs and symptoms

I should first clarify that it is almost impossible to find pasture, hay, grain or bedding that is completely mold- and mycotoxin-free. Although harmful levels of mycotoxins are generally rare, elevated levels — especially of certain types of mycotoxins — are a serious cause for concern.

Aflatoxicosis, which is defined as poisoning caused by the consumption of substances or foods contaminated with aflatoxin, is typically produced by a type of mold called Aspergillus flavus. This naturally occurring fungus thrives in the humid conditions we’ve experienced over the past year.

According to petMD, making a definitive diagnosis of aflatoxicosis is often difficult because the clinical signs can be non-specific and mimic several other serious conditions. Aflatoxin poisoning may be associated with any of the following:

• Depression
• Elevated temperature
• Yellowing of the skin and eyes (jaundice)
• Significant weight loss
• Abdominal pain (colic)
• Bloody feces
• Brown urine
• Recurrent airway obstruction (heaves)
• Ataxia (loss of coordination)
• Muscle spasms and/or seizures
• Death

While blood work may show raised levels of enzymes in the liver, among other fluctuations, samples from a living animal cannot conclusively diagnose the ingestion of aflatoxin. Instead, sampling the contaminated feed is recommended, although collecting a representative feed sample can prove challenging.

Treatment and prevention

If you suspect that your horse has ingested harmful levels of aflatoxin or any other mycotoxin, act immediately. You may choose to orally administer activated charcoal, which can absorb toxins and, as a result, help prevent them from being absorbed by your horse’s body. You must also remove any potentially contaminated feed sources.

Prevention is, of course, the best plan of action. Following the tips included below could help diminish your horses’ risk of exposure to potentially dangerous mycotoxins:

1. Keep feed storage areas clean, cool, dry and free of pests, which can chew holes in bagged feed, thereby exposing it to the elements.
2. When it comes to both hay and grain, feed old to new. Recognize when hay may be beyond appropriate fodder for horses and pay attention to the shelf life of grain — particularly if oil, molasses or other liquids have been added.
3. If you dump feed into storage bins or cans, it is important to regularly empty them and clean out the feed that gets stuck in the cracks and crevices of your containers.
4. Learn whether your feed manufacturer regularly tests their grain for mycotoxins — and avoid feeds from manufacturers who don’t.
5. Do not feed corn directly.
6. Always inspect your hay prior to feeding.

Our horses are truly our partners in equestrian sport, and it’s our responsibility to act as stewards on their behalf. Taking a little more time to be vigilant in your feeding practices will be well worth it and should help to alleviate worries about the potentially life-threatening outcomes associated with mycotoxin contamination.

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