How do bits affect a horse’s mouth? Gordon J. Baker BVSc, PHD, MRCVS, Diplomate American College of Veterinary Surgeons says, “There is a lot of fairly wide misunderstanding about where the bit is placed in the horse’s mouth and if it engages on the horse’s teeth. I don’t believe the teeth are tremendously involved in where the bit is.”
He notes that bits can cause mouth trauma if they’re in the wrong position or some discomfort if the teeth have points. “But when a bit is positioned correctly, it does not come in contact with the teeth. The bit engages the corners of the mouth. It’s not against the teeth at all.”
Hilary M. Clayton, BVMs, PhD, Endowed Professor, McPhail Dressage Chair in Equine Sports Medicine, Michigan State University, conducted a study on the position of English bits in horses’ mouth using fluoroscopy in real time. “Properly positioned English bits put pressure on the tongue and bars, perhaps also the palate depending on the type of bit and conformation of the horse’s mouth,” she found.
“Some horses have rather sharp bars, in which case there is more pressure, and even a fat bit can be uncomfortable if the rider takes more than a light contact. Other horses have a big tongue that completely fills the oral cavity. These horses have difficulty accommodating a fat mouthpiece.
“If the bit is too wide or too low, it is easier for the horse to elevate the bit between its teeth (there is more play in it). Horses seem less comfortable with a bit that hangs down on the tongue than a bit that is supported higher in the mouth. I like to see a wrinkle at the corner of the mouth with an English bit.”
Western bits ride further away from the commissure of the lip, where the upper and lower lip meet, says Raymond Q. Hyde, DVM, owner/president of the American School of Equine Dentistry.
“Western bits often ride so there is no wrinkle in the corner of the mouth. These horses are often ridden under a loose rein and so have less bit contact. But Western bits often have a curb action. If these horses have wolf teeth in the lower bars, they get a pinching affect by this bit.”
