Q: My 3-year-old grits his teeth and grinds his jaw whenever he is presented with a new task and he’s unsure or becoming stressed. His sire and three siblings did the same thing. What could be the cause of his teeth grinding? —Sherry Rosser Carroll, via Facebook

A: I know many people believe that if a horse is gritting/grinding his teeth, he’s in pain or in distress. For example, colicking horses will often grind their teeth; horses coming out of anesthesia post-surgery might sometimes grind their teeth; and horses with gastric ulcers might teeth grind.

However, I’ve known several horses that would grind their teeth when they were concentrating on a task that was newly learned or seemed difficult for them. For example, one dressage horse I knew would teeth grind when working on his flying lead changes, but the rest of his body language didn’t seem to indicate distress. As he became more skilled at that maneuver, the teeth grinding became less frequent.

Certainly it is always good to check for a medical reason behind teeth grinding (e.g., dental issues, gastric ulcers). But if the horse has been given a clean bill of health, I would just be careful not to overface this horse in his training. Ideally, it would be best to work on training this horse when he has not quite reached the arousal state of teeth grinding. Two reference articles you might find helpful include: