While there's no definitive cure for recurrent airway obstruction (RAO, commonly known as heaves), veterinarians are well-versed in managing the condition. Many will add a corticosteroid—either systemic or inhaled—to an affected horse's therapeutic regimen, but which type is the better choice?

Imogen Johns, BVSc, Dipl. ACVIM, MRCVS, a senior lecturer in equine medicine at the Royal Veterinary College, in Hertfordshire, U.K., sought to answer that question at the 2014 British Equine Veterinary Association Congress, held Sept. 10-13 in Birmingham, U.K.

Recurrent airway obstruction is an inflammatory lower airway disease similar to asthma in humans. Affected horses' airways are so obstructed by inflammation, mucus, and bronchial muscle contraction (bronchospasm) that the animal has difficulty breathing—even at rest. The condition is often caused by inhaled particles or irritants that end up in the horse's lungs, triggering airway inflammation