News Release Distributed 08/14/15

BATON ROUGE, La. – Horse owners need to watch out for signs of respiratory diseases that occur during the summer, said LSU AgCenter equine specialist Neely Walker.

Recurrent airway obstruction, formerly known as chronic obstructive pulmonary disease (COPD) or heaves, is a chronic, non-infectious condition that results from an allergic reaction to inhaled particles such as mold or dust from feed or bedding. A similar respiratory disease called summer pasture-associated obstructive pulmonary disease is caused by inhaling summer allergens, such as pollens, Walker said.

When a horse inhales allergens, a reaction may occur and constrict airways in the lungs. The lung tissue becomes inflamed and thickened, and excess mucus production occurs, Walker said.

“As the disease progresses, it becomes more difficult for the horse to exhale, leaving the lungs overinflated,” Walker said. “If this condition is left untreated, irreversible damage may occur to the lung, resulting in permanent loss of lung function.”

Recurrent airway obstruction usually occurs in horses 6 years old or older and those that are stalled for long periods of time, which increases exposure to allergens.

Symptoms include coughing, exercise intolerance, increased respiratory rate, nasal discharge, wheezing, weight loss and flaring of the nostrils. Owners may also notice a “heave line,” Walker said, if abdominal muscles are enlarged from the horse heaving, or pushing out the last bit of air when they exhale.

“There is no permanent cure for this disease, but complete or near complete recovery from the clinical symptoms can be achieved with appropriate environment management and medical treatment,” Walker said.

Horses that are sensitive to items such as bedding in their stall should be moved to a pasture with fresh grass, she said. If pasture allergens are the problem, the horse should be placed in a stall with low-dust bedding such as peat moss, shredded paper or cardboard.

Feeding a “dust-free” diet can also help, Walker said. Owners can soak hay in water prior to feeding or offer a pelletized feed such as a complete feed, hay pellet, hay cube or fermented hay.

Medical treatments may be necessary to alleviate the difficulty in breathing. Traditionally, anti-inflammatory medicines such as corticosteroids and bronchodilators are given orally or injected, although aerosolized treatments are now available, Walker said.

“Contact a veterinarian immediately if you suspect your horse has recurrent airway obstruction or summer pasture-associated obstructive pulmonary disease,” she said.

Olivia McClure