Air Quality Concerns for Stabled Horses



According to a recent study at Michigan State University (MSU), air quality may be worse for stabled horses than previously thought. Approximately 17 percent of the general horse population in Michigan has inflammatory airway disease, which affects athletic performance. Getting to the root of the problem and finding ways to prevent it is important.

Horses in the study were fitted with devices that measured the levels of endotoxins inhaled while in a stable and at pasture. Endotoxin levels at pasture were widely varied, but exposure in stables was approximately eight times higher than what outdoor horses were inhaling.

“In places where bacteria are plentiful, there are a lot of endotoxins. The main sources of endotoxins in the horse’s environment are manure, hay and straw,” says Dr. Frederik Derksen, DVM, PhD, Dipl. ACVIM, a professor at MSU who worked on the study. “Endotoxins become airborne easily. They attach to dust particles in the air, and when a horse inhales dust particles, he also inhales endotoxins.”

The problems don’t end there, as horses often have a severe reaction to these particles. “The body recognizes the endotoxins and thinks that it is being infected by [them]. The body’s response is inflammation, which results in mucus production, coughing and bronchospasm in the lungs,” continues Derksen.

Some horses may be more susceptible to this reaction than others. “Any horse that inhales a lot of endotoxins will have lung inflammation. This is most important in athletic horses, such as sport horses and racehorses, as their performance will be impaired,” says Derksen. “The inflammation will be most severe in horses that already have lung issues, such as heaves or inflammatory airway disease.”

There are management strategies that can be used to minimize this harmful level of exposure. “The best way to keep horses breathing good-quality air is to stable horses in a well-ventilated barn; frequently remove point sources of endotoxins (such as manure piles); and make sure that the hay and straw in the horse’s stall is not dusty,” Derksen advises. These tips should keep you and your horse breathing easier.

Liked this article? Here are others you’ll love:
Have a Healthy Barn
Ask the Expert: Ammonia Fumes in a Horse’s Stall
Ask the Expert: Help for a Horse with Heaves

This article originally appeared in the April 2009 issue of Horse Illustrated. Click here to subscribe.

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Holly Caccamise has been with Horse Illustrated and Young Rider since 2007, and in August 2019, she took over as head editor. She’s been instrumental in the production of both magazines and helped Horse Illustrated win a 2018 American Horse Publications Media Award in the General Excellence Self-Supported Publication (circulation 15,000 and over) category. Before getting involved in the editorial side of print media, she worked as an award-winning ad copywriter for Thoroughbred Times magazine. Caccamise has her MS in Animal Science from the University of Kentucky, where she studied equine nutrition and exercise physiology, and her Bachelor’s from UCLA in Biology. Caccamise has also worked as a research assistant, horse camp counselor teaching riding and vaulting, and as a top-level show groom in the eventing world, where she continues to compete her horse, Artie, at the lower levels.


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