Equine veterinarians and dealers will appreciate this extensive article as a resource when servicing horses and owners experiencing RAO (recurrent airway obstruction). Reps calling on equine vets and dealers may wish to share this article with customers as a resource for websites and for specific customers with chronic problems.
Source: Equus, December 2015, page 42. (direct link unavailable)
Once a horse has developed heaves, he will always be more susceptible to flare-ups when he encounters even small amounts of the substances that affect him.