How to Improve Air Quality in Your Barn

When winter hits, horse people have a tendency to shut those barn doors tight. But we may be doing our horses' respiratory systems a grave disservice. In winter, your horse may spend 24 hours a day in his stall. But the air in a barn with inadequate ventilation can very quickly become stagnant.

Practically everything in a barn environment contributes to poor air quality, from the dusts and molds lurking in hay, grain and bedding, to the ammonia fumes emanating from urine. Fungal material, bacteria and viruses, particles of fecal matter, methane, hydrogen sulfide, even microscopic bits of plant material and insect parts all are measurable pollutants in stables.

Poor Air Brings on Allergies

The dust that circulates in a closed barn can worsen allergies in horses of all ages, and this gets to be a big problem in older horses. The extreme example is the older horse with 'heaves', but earlier symptoms of cough and exercise intolerance can result from poor air quality in younger horses.

"Whenever you close up a building to keep it warm, the lungs have a price to pay," says Andrew Clarke, Director of the Equine Research Centre at the University of Guelph, Ontario, in Canada. There is also a demonstrated correlation between the incidence of infectious respiratory diseases, such as influenza and strangles, and stabling rather than keeping horses outside

We're beginning to understand how improving ventilation in barns and stables can improve or protect equine respiratory health. The ideal barn ventilation system distributes fresh air uniformly throughout the building, without causing drafts, at all times of the year. This serves to helps minimize your horse's exposure to environmental irritants, explains Clarke.

Gentle consistent air movement within a barn is important because it tends to sweep away the dust and mold particles, as well as airborne viruses and bacteria. Our tendency to close up any openings in a barn can interfere with normal ideal pattern air flow and trap those particles inside, along with moisture and noxious gases. Of course, not any airflow will do. If circulated air is chaotically causing turbulence, but is not replaced by outside air at a sufficient rate, dust will remain suspended, putting horses at further risk of greater exposure. Hence, a ventilation system needs to work right.

Sources of Dust and Mold

Sensitivities to dusts, molds and other inhalants vary a great deal from horse to horse, so it can be difficult to predict which horses will develop respiratory disease. But we can at least identify some of the common culprits.

Wood shavings can be problematic too. "One of the worst things you can do," says Clarke, "is to put your shavings pile right next to your horse's stall." Such a setup may mean your horse is regularly inhaling irritant particles.

One type of bedding that is unusually low in dust is shredded paper. The amount of airborne particles generated during mucking-out with this bedding, according to Raymond, was much lower than with straw bedding. Paper is a bit tricky to handle, however, as it requires very dry storage and becomes quite heavy when soaked.

Improving Air Quality

The inlets of a barn should be complimented by sufficient outlets, where warmer air escapes. Optimally, these would be located closer to the roof. The net effect is to encourage air to enter the bar, dip down, and rise when heated to exit higher up.