Improve Horse Barn Ventilation to Reduce Inhaled Dust

Even small amounts of inhaled dust may cause airway inflammation in horses. In fact, long-term exposure to low levels of dust can be just as dangerous as brief exposure to an extremely dusty environment. This was the conclusion of a study conducted by researchers at Michigan State University.

Endoscopic examinations were made every other month through late summer and fall to determine the amount of mucus in the trachea of 107 racehorses. Mucus secretion increases in response to irritation and inflammation and therefore is an indicator that horses have inhaled dust, mold, and other airborne irritants. The horses were kept in three stables and trained by different trainers. The barns were of various designs that influenced ventilation and exchange of air.

The researchers measured the dust concentration in every horse’s stall three times each day. Particles of dust, mold, and pollen were generally most prevalent in stalls where windows were small and ventilation was poor. Areas with low air movement, such as in the center of a barn, had high levels of dust. Dust was also prevalent in places where air was constantly in motion but was not replaced by fresh air. This included roads, tack rooms, in stalls near doors, and other areas of frequent travel by horses, people, or vehicles.

Similar levels of inflammation were found in the lungs of horses in stalls with constant low levels of dust and areas with periodic higher dust levels. Horses housed in barns with excellent ventilation (exchanging indoor and outdoor air, not simply stirring up the air inside the barn) have the best chance to avoid airway inflammation from inhaled dust. Ventilation can usually be improved by keeping barn doors and windows open and using fans to promote air exchange.