[header] How to treat allergies in horses [title] Don't feed your horse moldy hay. [step] Recurrent airway obstruction (rao), or " heaves, " is a respiratory condition in horses that can cause coughing and other issues. The condition is caused by irritating spores that can develop in moldy hay.
If you see hay that has the slightest bit of mold, get rid of it immediately. [substeps] Store your hay in a place that is protected from the elements, but not directly in or above your horse's stall, since this can expose the animal to allergens.