In the December 2005 issue of Horse & Rider magazine we talked about steps you can take to manage your horse's health and environment if he's been diagnosed with heaves. An acquired chronic allergic response that eventually diminishes your horse's ability to breathe, heaves can inhibit your horse's ability to perform. Your senior horse may be at risk, especially if he's been regularly exposed to dust, smoke and/or pollution over the course of his life.
So what are the warning signs? You'll typically observe a gradual progression of respiratory distress, usually without evidence or ongoing infection (no fever, and none of the other horses in the barn is sick). It may take weeks or years for the symptoms to interfere with your horse's ability to function. Here's a look at the typical progression.
1. Your horse shows signs of being easily winded.
2. A dry cough shows up later, and eventually becomes "juicier."
3. A thick nasal discharge may then appear, as evidenced by mucus on stall walls and/or in the feed bucket.
4. As the condition progresses, your horse's "air hunger" begins to preoccupy him. He's reluctant to do anything that might interfere with satisfying it, or that might make him feel more winded.
5. Breathing out becomes even more difficult than breathing in.
6. His abdominal muscles become overdeveloped from helping to aid his breathing efforts, forming a curved indention--called a heave line--along the side of his body.
For most horses, symptoms lessen or disappear in the pasture, but return with a vengeance in a stall.
If you suspect heaves in your horse, your veterinarian can perform a respiratory challenge test. In that test, a single dose of caffeine-related medication is administered. It'll cause dramatic but short-lived improvement if--and only if--heaves is a problem. Your vet will recommend a course of treatment or medications, but lung damage will continue unless you cut down on the allergens that are choking him.