Q: My 16-year-old gelding developed heaves after I moved him to a new barn. I’ve stopped riding him in the indoor arena and have seen some improvement, but I’m wondering if there is anything else I can try. He is kept in the stall half the day and turned out the other half—either during daylight hours or overnight, depending on the season. The bedding is a thin layer of shavings over mats, and the hay is a timothy mix that smells fresh.Name withheld by request

A: “Heaves” is the common term for recurrent airway obstruction (RAO), a respiratory disease characterized by inflammation and obstruction of the airways. Clinical signs may include cough, mucous discharge from the nose, exercise intolerance, weight loss, and significant effort upon exhalation, which over time may result in the characteristic “heave line” visible on the abdomen. Chronic exposure to airborne dust has been identified as an important risk factor for RAO.

Fortunately, when exposure to dust is minimized, it is possible for many horses with heaves to remain free of clinical signs. The general recommendation is to maintain them on grass pasture 100 percent of the time. This is not always possible or practical, however, so when horses with heaves must be stabled, it is important to manage their environment so as to reduce (eliminate) exposure to airborne dust as much as possible.

You’ve done a great job so far in minimizing your horse’s exposure to dust. Although the following is far from a complete list, you might consider adding a few more tactics for managing a horse with heaves:

  • Keep a daily journal. By recording details such as season, weather conditions, turnout schedules and stable events like new shipments of hay, you may be able to pinpoint conditions that trigger your horse’s heaves.
  • Improve ventilation. Keep stable doors and windows open as much as possible. If your horse’s stall does not have an open window, consider moving him to one close to a large doorway. If you use fans to improve ventilation, place them up and off the floor so they do not blow dust from the ground into the stalls/aisles.
  • Move horses outside when mucking and cleaning. Stall cleaning, raking/sweeping of aisles, removing cobwebs, throwing hay/straw down from lofts, leaving tractors or four-wheelers running in the aisles and similar activities generate high concentrations of particulates. Even after the initial “clouds” of dust disappear, very small particles, those that reach deep into the lungs, stay suspended for quite a while. If you must do these types of chores while the horses are inside, consider using water to help control dust levels.
  • Switch to a “complete feed.” If this isn’t practical and you must feed hay, wet (don’t soak) it thoroughly—so that the water drains through—prior to putting it in the stall. Also, divide hay into multiple small feedings over the course of the day. This may reduce the horse’s tendency to “dive in,” grab and shake the hay, which produces high concentrations of dust around the nostrils. Placing the hay either on the floor or as low as possible helps mucus to drain from the air passages. And, of course, do not throw hay up and over stall walls.
  • Minimize arena dust. With a garden hose and rotary sprinkler to wet the surface, you can greatly reduce dust in indoor and outdoor arenas. Commercial dust suppressants remain effective longer than water and may be more practical during the winter months.

It is virtually impossible to eliminate dust from your horse’s environment,
but you can make a big difference by focusing on what triggers your horse’s signs and then implementing just a few environmental control strategies that make sense in your situation.

Melissa Millerick-May, PhD
Michigan State University
East Lansing, Michigan