May
27
Written by:
Surgi-Care Center for Horses
5/27/2011 4:28 PM
Heaves, also known as chronic obstructive pulmonary disease or COPD, is an inflammatory condition of the lungs. It is a common respiratory disease that develops in older horses (greater than 7 years old). It is characterized by bronchospasm, excess mucus production, and changes in the bronchiolar walls (airways in the lungs). Heaves is thought to be a hypersensitivity reaction to molds and dusty hay. In the northern United States, it is typically a problem of horses that are stabled, whereas in the south, it is more commonly a problem of horses that are out in pasture. Heaves is similar to another disease, known as inflammatory airway disease, or IAD. This disease is usually milder than heaves, but can have similar clinical symptoms. It is more common in young horses, whereas heaves is more common in older horses.
The clinical signs associated with heaves typically worsen over time. Initially, in the early stages of the disease, the horse may show mild exercise intolerance with an occasional cough at the onset of exercise or when eating. As the disease progresses, the frequency and severity of the cough worsens. In severe cases of heaves, the horse will have an increased respiratory rate, increased respiratory effort, flaring nostrils, and a “heave line” may develop. A “heave line” is an imaginary line along the sides of the thorax from overexertion and thus an over-development of the respiratory muscles due to increased effort of breathing.
The diagnosis of heaves is established by history and physical examination, lung radiographs, and transtracheal aspirate or bronchoalveolar lavage. The transtracheal aspirate and bronchoalveolar lavage are both tests in which a sample of the fluid from the airways is obtained. This test provides the definitive diagnosis of heaves.
Treatment for heaves ranges from changing environmental factors to drug therapy. Environmental changes involve decreasing exposure to dust. Unless pasture exacerbates the condition, the horse should be kept outside as muc h as possible. When stabling, it is best to avoid fine/dusty shavings for the stall bedding. Instead, try bedding the stall with straw, wood chips, or peanut kernels. Also, a complete pelleted feed would be ideal to replace the dust and allergens in hay. If you do not want to eliminate hay from the diet, it is best to soak the hay for at least 2 hours prior to feeding. Finally, consider wetting the barn aisle prior to sweeping to reduce dust formation in the air.
Medical therapy includes coricosteroid s (dexamethasone, triamcinolone, etc) and bronchodilators (clenbuterol, albuterol, etc). Both, corticosteriods and bronchodilators, can be administered systemic (orally, in the vein, or in the muscle) or can be inhaled. Medications can be inhaled by using an Aeromask. This is a mask that is placed over the muzzle (nostrils and mouth). The desired medication can be attached to the mask and can be pumped into the mask. The horse then inhales the medication when he/she breathes. This is very similar to asthmatic people that use an inhaler.
Some owners elect to try and eliminate environmental factors initially, and if that alone does not resolve clinical signs, they try medical management. Other owners elect to try both environmental and medical treatments simultaneously. Different factors such as the severity of the disease, length of time the disease has been going on, client compliance with treatment, established environmental conditions, and financial limitations all factor into the optimal treatment option for an affected horse. It is best to have your horse evaluated by your veterinarian if you suspect your horse has heaves. If heaves is diagnosed, work with your veterinarian to establish the most effective treatment plan.
Contact
Surgi-Care Center for Horses at 813-643-7177 or
email lkuebelbeck@surgi-carecenter.com with
any questions regarding this topic.