Diagnosing Mild Equine Asthma. Veterinarians and engineers at the Purdue University College of Veterinary Medicine have developed a tool help diagnose mild forms of horse asthma. Behind lameness, respiratory issues are the second-leading cause of poor performance in sport horses but often, symptoms are subtle and difficult to spot, particularly when they are non-infectious and only affect the horse during high intensity exercise.
Purdue is one of only three University large animal hospitals in the United States that have a cutting edge sports medicine and respiratory testing program. They use a high-speed treadmill to test equine athletes that show decreased performance. By reproducing the strenuous exercise horses do in real training and measuring things like heart rate and blood oxygen level as they run, the high-speed treadmill allows veterinarians to detect whether the problem is a breathing problem, a heart problem or a muscle problem.
Nevertheless, detecting subtle cases of horse asthma has, until now been problematic. Horse asthma is a diagnosis that encompasses two forms of non-infectious respiratory disease; inflammatory airway disease or IAD (a non-infectious inflammation of the respiratory tract which can be mild and undetectable at rest), and recurrent airway obstruction (a more severe condition), also known as RAO or heaves.
The innovation developed by Purdue’s research team is a variation of the most common test performed for asthma in humans, ‘forced exhalation’. The test requires the patient to be trained to take in the deepest breath possible and blow out as hard as possible, so doctors can measure how quickly they can blow out, and until now it has been impossible to replicate in horses.
Led by Purdue’s Equine Sports Medicine Center Director Dr. Laurent Couëtil, the research team at Purdue have managed to develop a variation of the human exhalation test that can be performed on horses.
Horses are partially sedated while they are standing. An apparatus attaches to two different tanks; one tank with positive pressure connects to the horse’s airways to inflate his lungs. Next, a tank with negative pressure (like a vacuum) forces the expiration in the horse.
The automated system produces measurements that can diagnose the horse’s respiratory condition more accurately. Once identified, Couëtil says asthma is relatively easy to treat in horses with medication, special devices similar to human inhalers and reducing dust from forages and the horse’s housing and environment.
Couëtil says, in its current form, the technology requires equipment that’s too large for portability. The test is also “quite involved” and requires specialized expertise. His lab is working to create a more simplified—and smaller—system that could be commercialized for veterinarians to diagnose asthma in the field.
With a study showing 80% of horses with respiratory issues had mild forms of asthma, it’s likely this technology will eventually help many horses, from elite racing athletes to others like Love Bug who is featured in the promotional video, a dressage pony that is already benefiting from the new diagnostic tools available at Purdue Large Animal Hospital.