Feed gone foul.

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Fusarium-contaminated feed can put horses at risk. An article by Lisa Caines.

Even picture-perfect horse feed can have minute hidden amounts of a toxic fungus called Fusarium that may affect performance. Susan Raymond of Equine Guelph is determining how feed containing wheat or corn that’s contaminated with Fusarium mycotoxins — toxins produced by fungus — affect the animals that eat it.

“High levels of Fusarium mycotoxin con-tamination produce symptoms that horse owners and caregivers can see, but the effects of low levels of contamination on horses haven’t been explored extensively,” says Raymond. “It’s still unknown what levels of Fusarium mycotoxins are considered safe, and we want to see if contaminated grain affects a horse’s ability to perform athleti-cally.”

At high levels, Fusarium mycotoxins sup-press a horse’s appetite and impair its repro-ductive ability and athletic performance. Its immune system is also suppressed, making the animal more susceptible to infections. To test how low levels of Fusarium myco-toxins affect horses, Raymond and her team fed individual horses one of three types of feed, including one that was naturally contaminated with Fusarium mycotoxin levels commonly seen in the industry. During the trial, the researchers had the horses run on treadmills to mimic the athletic demands of the racing industry. They collected blood samples while the horses were at rest, during running and afterwards.

“In the horses eating the naturally con-taminated grain, we saw a level of feed refusal and weight loss,” says Raymond. “We are currently examining results of the blood samples, specifically looking for elevation in liver enzymes. That means the mycotoxins could make them more susceptible to liver damage.” Raymond says horse owners can reduce mould exposure by buying high-quality forage, grain and bedding. She also recom-mends low-moisture storage, where moulds are unlikely to multiply.

“People should be proactive in knowing how crops are grown and stored,” she says. “For many people, it’s still an unknown prob-lem and it varies with the season.”

This research is sponsored by the Ontario Ministry of Agriculture and Food, the E.P. Taylor Equine Research Fund, the Ontario Horse Racing Industry Association and Alltech Inc.