If a horse is confined in a barn during winter, he is at risk for respiratory problems. Heaves is the most common respiratory ailment in horses that are confined indoors or fed dusty hay. Heaves is characterized by chronic cough, lack of stamina, labored breathing, weight loss, lack of response to antibiotics, and sometimes a watery discharge from the nostrils. It is most common in adult horses since prolonged exposure to respiratory irritants brings on the reaction. The breathing difficulty is due to inflammation and swelling that narrows the air passages.

The main symptom, from which the term heaves is derived, is a forced effort to exhale, sometimes described as double xpiration. Air is drawn in easily, but the horse has trouble pushing it out. Forcing it out requires two movements of the abdominal wall (double expiratory lift). The horse has to tense his abdominal muscles to force the air out, giving an exaggerated lift of the flank. Many horses develop an enlarged ridge of muscle along the lower edge of the abdomen from overworking these muscles.

Decreased speed and stamina may be the only symptoms of early heaves, but as the problem progresses the horse has more trouble breathing, eventually developing a large chest and potbelly because diaphragm muscles enlarge. If he has to breathe deeply, as when exercising, he coughs. The coughing spells are also brought on when eating dusty hay.

Whenever a susceptible horse is in an enclosed barn where there is dust or mold spores, his airways become hyper-reactive. The airway walls thicken (reducing their diameter), they produce excess mucus, which tends to block them, and the muscles in the airway walls contract, further constricting the airways.

Even if a horse with heaves is turned out into a non-dusty environment it may take weeks for the inflammation to disappear. If put back into the barn, even for a short time, he will relapse. A horse with this problem must be protected from dust as much as possible and fed dust-free hay or pelleted feed. Pasture is best. A horse with a respiratory problem should not be kept indoors.

Once a horse develops heaves, the only solution is a dust-free environment. For winter, an open three-sided shed with no bedding and a diet of dust-free pellets or water-soaked hay can often keep the horse from relapsing. Even a few minutes of dust in an indoor stall can start a chain of events that will cause several days of breathing difficulty.

Each time the horse experiences an episode of difficult breathing he becomes a little worse. Even if a horse is kept outdoors, he may relapse if brought into the barn for just one night or even just for grooming or saddling.

If you must use hay for a dust-sensitive horse, soak each flake first in a tub of water to moisten it completely, then drain it well before giving it to the horse. If grain is fed, give it as a mash or with molasses added to reduce dustiness. None of these efforts, however, will help if the horse is indoors and other horses in the barn have dusty straw bedding. There will be dust particles floating in the air.

About the Author

Heather Smith Thomas

Heather Smith Thomas ranches with her husband near Salmon, Idaho, raising cattle and a few horses. She has a B.A. in English and history from University of Puget Sound (1966). She has raised and trained horses for 50 years, and has been writing freelance articles and books nearly that long, publishing 20 books and more than 9,000 articles for horse and livestock publications. Some of her books include Understanding Equine Hoof Care, The Horse Conformation Handbook, Care and Management of Horses, Storey's Guide to Raising Horses and Storey's Guide to Training Horses. Besides having her own blog, www.heathersmiththomas.blogspot.com, she writes a biweekly blog at http://insidestorey.blogspot.com that comes out on Tuesdays.

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