Selenium Overdose Blamed In Polo Pony Deaths
Toxicology tests have confirmed suspicions that selenium overdose was the cause of the sudden death of 21 polo ponies in Florida. The pre-event supplement the horses received was suspected early in the investigation, and the compounding pharmacy that provided it confirmed that the selenium level turned out to be too high. They would not say whether this was due to a pharmacy error, or if the wrong amount of selenium was specified on the original veterinary order.
While this is hopefully an extremely rare event, it raises questions about what we give horses and why. The amount of money that is spent on supplements for horses is astounding. It's questionable whether most (or any) are needed, even for the highest level performance horse - yet a large percentage of horses, including "backyard" pleasure horses, are regularly treated with a variety of unproven supplements. I'm not saying that all supplements don't work, but for most of them there's just no evidence that they do work. There are also issues with quality control, as has been clearly shown with probiotics and glucosamine supplements.
Using supplements is very clearly a "buyer beware" situation. Most supplements have not been shown to be effective. Most are likely safe, but toxic reactions to some compounds (especially some herbs), contaminants and mixing errors can occur. Supplements are also a concern in terms of positive drug tests if their contents are not very clear, if they contain small amounts of contaminants, or if the contents have similar properties to tested drugs.
Am I saying stop using supplements? No. What I'm saying is think before you buy. Don't fall for flashy sales pitches and testimonials. Don't use a supplement because "everyone else is using it." Remember the general rule: above all, do no harm.
