Horses with equine asthma can present with a wide variety of clinical signs depending on the severity of the disease. Owners and veterinarians can typically recognize severe asthma easily based on increased respiratory rate and rhythm at rest, plus a cough. Horses with mild asthma, however, might simply have poor performance. And horses with moderate asthma generally present with a cough and potentially other clinical signs suggestive of respiratory tract obstruction due to bronchospasm (a temporary constriction of the airways into the lungs caused by muscle contraction) and lower airway inflammation.

Overall, veterinarians might be underestimating the number of horses suffering from asthma. An economical and relatively easy-to-perform stallside test could help them better identify and manage these horses.

“Currently, diagnosing asthma involves performing a complete physical examination in conjunction with a bronchoalveolar lavage (BAL), more commonly referred to as a lung wash,” says Jean-Pierre Lavoie, DMV, Dipl. ACVIM, a professor and the director of the Equine Asthma Research Laboratory at the University of Montreal, in Canada. “In some areas, however, a BAL cannot readily be performed due to logistics, economics, or other reasons.”

The Question: Could Biomarkers Provide an Alternative?

Instead of a BAL, Lavoie and colleagues suggested veterinarians could use biomarkers circulating in the blood to identify the presence of mild or moderate asthma. Biomarkers are measurable substances in an organism whose presence is indicative of some disease, infection, or environmental exposure