Dust control methods to protect horse airways

Why the dust you can't see is the real problem

If your horse coughs at the start of work, has a runny nose, or seems to tire faster than he should, the air in your barn may be the cause. The dust that settles on tack trunks and rafters is annoying, but it is not the main threat. The particles that damage horse airways are the respirable ones — small enough to bypass the upper airway and reach deep into the lungs, where they trigger inflammation and allergic responses (Green Horse Brands).

Horses are obligate nasal breathers with a high oxygen demand, which makes them especially vulnerable to airborne dust and ammonia (Mad Barn). Dust from hay, bedding, and poor storage carries mold spores, bacteria, and mites. Ammonia from urine-soaked bedding irritates respiratory tissue, and manure gases and cleaning chemicals add fumes. Together these can drive recurrent airway obstruction and inflammatory airway disease.

Barn staff face the same risks, including chronic coughing, asthma aggravation, skin irritation, and hypersensitivity pneumonitis. Dust control is therefore a safety standard issue, not just a comfort issue.

Start with bedding and forage

Bedding and hay are the two biggest controllable dust sources in most barns.

• Choose low-dust bedding. Straw quality varies, and even clean straw contains spores that irritate airways. Wood shavings, cardboard, or paper bedding have been shown to greatly reduce dust in the stall (Kentucky Equine Research).
• Steam or soak hay. Steaming hay reduces respirable irritants commonly found in forage — including bacteria, mold, and dust — by up to 99% (Haygain). Soaking is a practical alternative when steaming is not available.
• Feed at the right height. Feeding hay off the ground or at chest level keeps the horse's breathing zone away from the floor where particles concentrate.
• Store forage away from stalls. Hay and straw stored in or above stalls shed dust and spores directly into the air horses breathe.

Fix ventilation before you buy equipment

Ventilation is the single most effective long-term control. Without adequate air exchange, dust and ammonia accumulate no matter how clean you keep the stalls.

• Target 25 cubic feet of air per minute (cfm) per 1,000 pounds of horse as a minimum winter ventilation rate (University of Minnesota Extension).
• Aim for 4 to 8 air changes per hour to reduce mold spore contamination (Riding Magazine).
• Use continuously running sidewall exhaust fans rather than relying on opening doors and windows, which is inconsistent and often closed at night.
• Keep inlets open. Research on Norwegian stables found that half had lower calculated air exchange rates than recommended, largely because managers closed doors and inlets manually at night (Journal of Equine Veterinary Science).
• Watch humidity. Very dry air dries the nasal mucosa and allows dust and pathogens deeper into the airway; very moist air reduces the coat's insulation and causes condensation (Ontario Ministry of Agriculture).

Daily management checklist

Small habits make a measurable difference. Use this list as a weekly audit.

1. Remove wet bedding and manure at least once daily; more often in hot weather.
2. Sweep or damp-mop aisles instead of dry sweeping, which lifts fine particles.
3. Dampen feed or use pelleted feed to reduce particles.
4. Keep stall fronts and fans free of settled dust.
5. Check that fans are actually running and inlets are not blocked.
6. Watch horses for coughing, nasal discharge, or increased respiratory effort — persistent signs mean the air quality needs attention.
7. Have your veterinarian assess any horse with recurring respiratory signs early.

What good air quality looks like

You do not need a laboratory to judge barn air. Stand in the stall for a few minutes. If you smell ammonia, if dust is visible in a beam of light, or if you cough, the air is not good enough for a horse that spends most of the day inside. Fixing bedding, forage, and airflow in that order usually solves the problem before you spend money on air purifiers or supplements.

How the Featured Expert Can Help

Randi Thompson is an equine industry expert witness and consultant with over 45 years of experience. She founded the Equine Safety and Success Network (ESSN) and the Equine Safety and Success Guide (ESSG), which focus on safety standards, risk management, and operational protocols for equine facilities. If you need guidance on barn air quality standards or want to document your protocols, visit randithompsonlive.com.

Quiz: Test your dust control knowledge

Which ventilation rate is the recommended minimum winter rate per 1,000 pounds of horse?

• 25 cfm
• 5 cfm
• 100 cfm

Answer: 25 cfm per 1,000 pounds of horse is the minimum winter ventilation rate recommended by University of Minnesota Extension.