Horse Disease Focus - Heaves
What Is Heaves?
Heaves is a chronic respiratory disease that affects horses. It is also called recurrent airway obstruction and COPD (It is somewhat similar to human COPD, but has different causes).
The disease predominantly affects stalled horses. It usually first shows up at around the age of eight. However, some pasture kept horses in the southern US may get a form of heaves in the summer. There also appears to be a genetic element to the disease, explaining why not all stalled horses are afflicted with it.
The symptoms of heaves generally show up at about the age of eight. Initially, the horse will cough when worked and show exercise intolerance. If the disease progresses, the animal may cough and have difficulty breathing even at rest.
Horses with advanced heaves often develop a 'heave line' that runs from the point of the hip to the lower edge of the ribs. This is caused by over-development of the muscles that operate the diaphragm from constant breathing difficulty. However, extremely fit working horses often also have a line, but it is shallower and does not come quite so high at the back...this is caused by the horse developing its core strength and tends to be most obvious on endurance horses and high level dressage mounts. The presence of an abdominal line on a horse is, therefore, not diagnostic of heaves unless the horse is otherwise in poor condition or unfit and demonstrating respiratory distress.
Horses with untreated heaves often end up under weight because they find it harder to eat and are focusing on breathing.
Heaves is not a curable condition. If a horse has heaves, it will have heaves for the rest of its life.
However, horses with heaves can be managed and have a happy, long and useful life. The primary treatment for heaves is to remove the horse from the heaves-inducing environment. In almost all cases, this means turnout.
A horse with heaves should be turned out twenty-four hours a day, seven days a week and should be brought in only when needed for work. If it is absolutely necessary to stall the horse, then the stable needs to be very well ventilated and dust mitigation techniques should be used. Dust mitigation is a good idea for all horses (especially as stable dust can also be an allergen for humans and barn pets). Arena footing should be kept slightly moist, tractors should not be left idling in barn aisles (this is also a fire risk), and leaf blowers should never be used inside.
Horses with heaves should never be fed dry hay. Instead, their hay should be soaked for at least thirty minutes in room temperature water before feeding. Low dust hay pellets can also be fed. When the horse does have to be indoors, it should be kept in a stall with rubber matting and absolutely not bedded on straw.
In some cases, the vet may prescribe either bronchodilators or corticosteroids. However, these are a less effective treatment than lifestyle changes and are generally only used for the short term treatment of a horse with advanced heaves, in order to bring the condition under control quickly. Corticosteroids, in particular, should not be used for long periods as they have been associated with laminitis, and should never be given to a horse with Cushing's disease.
Some experiments have been done with desensitization (such as is done in human allergy treatment) for heaves, but proper controlled trials have yet to be done.
The best treatment for heaves is to turn the horse out, and all horses benefit from as much turnout as logistics allow. A pastured horse is much less likely to develop heaves in the first place.
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