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Mycotoxins a hidden menace for horses

Horses can be exposed to mycotoxins by eating contaminated feed ingredients, such as concentrates (e.g., grains and protein supplements), hay and green pasture. The extent of mycotoxin exposure depends on how much of the contaminated ingredient is fed and the mycotoxin concentration present in the feed. Any feed ingredient may contain multiple mycotoxins, which can become more toxic together than they would be individually.

Mycotoxins in horses can cause a wide range of clinical signs, including respiratory, gastrointestinal, neurologic and reproductive problems. Obvious signs may include tremors, fever, loss of appetite, bloody faeces, brown urine and, in extreme cases, death.

Diagnosing mycotoxins is a big challenge. Confirmation of a diagnosis usually requires sample testing by a reliable, accredited laboratory. The sample may test positive for mycotoxin presence, but that does not mean the whole batch of hay or feed is contaminated. Mouldy feed should be treated with extreme care and preferably not fed to your horses. To minimise problems, it is best to buy from a reputable dealer or producer. The feed or hay should be stored so that it is protected from moisture and has space to allow air to circulate around the product.

There is no easy solution for mycotoxin prevention. It has been said that mycotoxins are everywhere and especially so when humid, hot and moist conditions are present. In research work, some products have been shown to alleviate some of the negative effects of mycotoxins on horses. It is common for people to add mycotoxin binders to their horse’s ration. However, care should be taken to choose a binder that has research published on horses. Binders are more effective if applied at the time of feed production, but they can also be added to the horse’s daily feed by the owner. Ideal mycotoxin binders should bind multiple mycotoxins at low dosages and should have strong peer-reviewed research support.

Mycosorb® from Alltech is widely respected in the equine community and is one of the very few products to receive legal registration for use in animal feeds. To learn more, visit