In study that could have been dubbed "Who's smarter than a veterinarian?" Michigan State University researchers concluded that when it comes to assessing chronic respiratory disease changes in horses, the answer is … owners.

"Owners are astute observers of their horses and are able to accurately differentiate the improvement in respiratory signs in horses treated with dexamethasone from the lack of improvement in placebo-treated horses," said Ed Robinson, MRCVS, PhD, Matilda R. Wilson Professor of Large Animal Clinical Sciences, who led the research team.

Inflammatory airway disease (IAD) and recurrent airway obstruction (RAO, heaves) are noninfectious conditions characterized by airway inflammation and obstruction, excess mucus accumulation, and alterations in airway structure of affected horses (i.e., remodeling). Corticosteroids such as dexamethasone and bronchodilators like clenbuterol are the most commonly used drugs to relieve airway obstruction in affected horses.

"The best way to assess the efficacy of these drugs is by lung function tests," explained Robinson, but he notes these test are technically challenging and do not detect small changes in obstruction severity. Robinson noted another challenge for veterinary assessment: While owners often assess their horses daily, practitioners examine clients' horses infrequently and might not see these horses at their worst (e.g., after exercise)