KISS AND TELL
As you finish brushing your horse’s face, take a moment to give him a quick kiss on the nose. In addition to expressing your affection, this gesture serves the practical purpose of enabling you to sniff his breath.
A normal horse’s breath will have no detectable odor, aside from a whiff of sweet feed or maybe wild onions if he’s recently grazed in spring pasture. Any unpleasant odor is reason for concern. Dental and sinus infections have a distinct “rotting” smell, as do some advanced tumors.
If you smell anything foul near your horse’s nostrils, call your veterinarian. A complete dental exam and, possibly, an endoscopic investigation, will likely uncover the source of the problem.