The bit is a tool of communication, not of punishment. That, says Dwight Bennett, DVM, PhD, professor emeritus at Colorado State University, is the most important thing any horse owner can understand about bits. If a bit is causing pain or discomfort, communication breaks down and your horse’s performance, as well as his mouth, suffers.

“Fifty percent of a rider’s communication with the horse is done through the bit and reins,” says Alixe Etherington of John Dewsbury Bits in Tweedale, England. For clear communication to take place between a horse and rider, the bit must sit correctly and comfortably in the horse’s mouth, and a pair of soft, understanding hands must hold the reins.

The signs of bit pain in the competition horse can surface as a missed lead, a dropped shoulder, or a second of resistance during transitions, says Teri Olson, licensed veterinary technician and equine dental lab instructor at Washington State University in Pullman. Bit pain also can emerge as a headshaking, mouth-gaping, tongue-lolling refusal to perform, adds barrel race bit designer Carol Goostree of Verden, Okla.

Whether subtle or blatant, your horse’s defiance might baffle and frustrate you and your trainer. You could even misinterpret your horse’s behavior as stubbornness, lameness, or a training problem when, in fact, the problem lies in his mouth.

Bits, depending on the kind of bit and style of bridle, can work on seven points of the horse’s mouth, face, and head–the tongue, corners of the mouth, bars, teeth, palate, chin curb, and poll. English riders tend to keep more contact with the horse’s mouth, and Western riders typically use curbed or leverage bits in their more advanced horses. But, English or Western, snaffle or curb, bit pain and its causes are universal to all horses.

The Rider’s Hands

The Problem–The biggest problem causing bit pain doesn’t necessarily have to do with the type of bit used or the specific horse. The problem, whether through lack of experience, frustration, or deliberate abuse, is often in the rider’s hands.

“Any bit can be severe in the wrong hands,” Goostree says.

Novice riders often seek balance through their arms and off the bit, causing soreness in corners of the horse’s mouth and creating calluses, which deaden response. Angry riders sometimes pull forcefully on the reins, which can cause acute injuries such as lacerations, swelling, and bruising on the horse’s palate, bars, and tongue. The result is a horse that either avoids or fights the bit and loses focus on his job.

The Solution–“You have to have a good seat before you have good hands,” says Bennett. “The good rider stays off the horse’s mouth and rides with his or her seat and legs.”

The best way to develop an independent seat is through lessons and time spent in the saddle. Riding on the longe line can also help a novice gain experience and balance on the horse’s back without sacrificing the horse’s mouth.

Riders who use the bit as punishment need to rethink their methods and understand the pain they’re inflicting on their mounts, as well as the possible permanent damage abuse can inflict on a horse’s mouth.

Past Damage

The Problem–Past abuse to the horse’s mouth causes him to resent the bit and his rider, and even proper use of the bit can cause pain by aggravating existing injuries. Goostree warns that once the horse’s mouth is damaged, it might be damaged forever.

The horse’s tongue is the most sensitive part of his mouth and the most likely place to sustain injury from a poorly fit or misused bit. “You’d be surprised by how many horses have visible damage in their mouths,” Bennett says.

Looking at an injured tongue, you can often see scar tissue and, Bennett says, sometimes even a deeply dented impression from side to side caused by the bit cutting through the sensitive tongue tissue.

The bars of the mouth, where the bit sits in the inter-dental space, can also sustain chronic injury from the misuse of the horse’s mouth. “Some people seem to think if they can make the bars of the mouth sore, the horse will respond better,” Bennett observes. “That’s backwards thinking. The best example is a teething baby (human) with sore gums who wants to bite down on something hard. A horse with sore bars will tend to lean into the bit rather than stay off it. In some cases a horse with develop a mandibular periostitis, where the bone underneath the bars becomes inflamed and quite painful.”

The Solution–Some cases of mandibular periostitis require surgical intervention. Milder cases require rest to reverse the symptoms of injury.

While damage is often permanent, a patient rider with sensitive hands can sometimes rehabilitate a “ruined” mouth. And, says Bennett, a horse with a damaged mouth can often find relief in bitless bridles, such as bosals or hackamores. He warns that these bitless tools can also cause pain for a horse if used by inexperienced or hard hands.

The Wrong Bit

The Problem–You’ve ruled out all exterior causes of pain, but your horse still isn’t comfortable with the bit. He either doesn’t respond at all or fights the signals you send through the reins. You’re trying to communicate with your horse, but the bit just seems to be in the way.

Another mistake riders make is using a more severe bit to get a response from the horse. “One of the real misconceptions I’ve observed is that riders sometimes think that if a horse isn’t ‘respecting’ the bit, they need to go to a more severe bit,” Bennett says.

Typically, more severe bits are meant for more highly trained horses and riders, not the other way around, Bennett says.

The Solution–Find the bit that works for you and the horse. “So many times when people buy a barrel horse, they’ll say, ‘I want the bit that goes with him,’ ” Goostree adds. “Sometimes it works and sometimes it doesn’t, because the previous rider’s hands are totally different. You have to find a bit that works for you and for the horse.”

On the same note, just because a bit has worked for you on past horses doesn’t mean it is right for a new horse.

“I want a bit that’s as comfortable for the horse as I can get it while still getting him to respond,” Goostree says. She also warns against using too mild of a bit, which can cause confusion for the horse or possibly allow the horse to ignore important signals from the rider.

Goostree points out that many riders seek miracle cures in bits marketed to fix horses’ behavioral problems. “And sometimes the bit does fix their problem,” she says. “But often, riders just need to go back to some basic training.”

Bit Fit

The Problem–Your horse’s bit doesn’t fit his mouth or jaw. The bit is either too wide or too narrow against the outer corners of the lips, or too fat or too thin inside the horse’s mouth. A poorly fitted bit can cause a horse to loll his tongue, which in turn can obstruct airflow or inhibit swallowing during exercise. An ill-fitted bit can also rub and cause irritation to your horse’s mouth corners, bars, or tongue.

Another bit fit problem is caused by an incorrectly adjusted bridle, which can pull a bit too tight in the mouth, causing pinching and tension, or drop the bit too low, where it can bump against the canine teeth or buds.

The Solution–“Every horse’s mouth is different,” Goostree says. “It’s shaped differently and the size of the tongue is different.” She adds that a rider must fit the bit to the horse, not the other way around.

“Everyone should go out and take a look at their horse’s mouth,” Bennett says. By inspecting your own horse, you can see what his specific anatomy looks like.

Horses’ tongues vary in shape and size, so look to see if his tongue fills his mouth or presses against his teeth. Also, check to see if his tongue is thick, which will cause a fat bit to ride higher in the mouth and possibly press toward the horse’s hard palate.

A study by the University of Hanover, in conjunction with German bit company Herm Sprenger, found that average palate height is dramatically different from horse to horse. The study found that the palate lowers significantly in an individual with age, but there’s no consistency of palate height between animals. So, as your horse ages, make sure your bit continues to fit him.

If the bridle adjustment is the problem behind your bit fit, readjust it. A bit should be about a half-inch wider than the corners of your horse’s mouth. A snaffle should rest with a wrinkle in your horse’s mouth corners, and a curb or leverage bit should hang lower in the mouth, but without hitting any teeth.

Also with a leverage bit, make sure the curb strap is adjusted correctly. “People always want to set a curb strap by how many fingers you can put between it and the chin, and that really doesn’t make any sense,” Bennett says. “What you want to do is decide how much you want the bit to rotate and set the curb accordingly.”

The more “signal” a leverage bit has, the more you have to pull the reins for it to engage. The more you tighten the curb strap, the more you take the signal out of the bit. Along the same lines, a bit with straight shanks will give very little signal and engages quickly. “Most training is based on pressure and release, so riding the horse with a swept shank, or the so-called grazing bit, will release more quickly and reward the horse for his response,” says Bennett.

Bit Quality and Care

The Problem–You compared two seemingly similar bits, one $10 and the other $100. After examining the bits, which share the same design, you opt for the least expensive one. But Etherington warns, “You get what you pay for.”

The inexpensive bit, while it looks the same as its more expensive counterpart, usually isn’t made with the same care or as high-quality alloys. Also, the inexpensive bits usually aren’t packaged and shipped by the manufacturer as carefully as more expensive ones and can become damaged before they hit the retail shelves, Etherington explains.

Poor manufacturing and damage often mean an imperfect bit with chips, rough edges, and sharp seams. Or maybe you’ve used the same bit for the past decade, and it’s seen better days. Over time, the bit has developed sharp edges and grooves from daily use. Either way, a bit with sharp edges or deep groves can cause irritation and sores in a horse’s mouth, Etherington says.

The Solution–Splurge on a high-quality bit from a reputable manufacturer, and before you buy the bit, look at it closely and run your fingers along it looking for any rough seams or edges.

After you buy a high-quality bit, inspect it regularly, just as you should all of your tack. Look for any wear or damage to the bit that might, in turn, damage your horse’s mouth. As soon as your bit starts to deteriorate, replace it with another new, high-quality bit.

Dental Demands

The Problem–Points on your horse’s teeth create irritation and discomfort on the inside of his cheeks. “Most people don’t realize that even a 2-year-old colt can have points on its teeth that can be corrected,” Olson says. “If you go to put a bit in that colt’s mouth with points, then the horse is going to start associating the bit with pain. The very front premolars are triangular and come to a point in the front. So, when you take that triangular portion and press soft tissue against it, it can be painful. Then you put a bit in the mouth and start manipulating the bit; it can cause pain.”

The Solution–Rule out any tooth-related bitting issues by getting a full dental exam for your horse by a qualified veterinarian or your veterinarian’s associated dental technician. Dental problems for your horse, including hooks, ramps, steps, waves, and sharp points, can stand between the correct bit and a perfect performance, so regular dental care is an essential part of any performance horse’s program.

Also, your veterinarian might need to surgically remove your horse’s wolf teeth if they bump or pinch against the snaffle bit, which is carried higher in the mouth than a leverage bit.

Olson recommends routine yearly or twice-yearly dental examinations to prevent health and bitting problems. “Don’t wait until the horse is old and dropping feed to get his teeth checked,” she says.

In fact, dental care is at least as important, or possibly more important, for young, growing horses. “It would be great if we could get in all horses’ mouths when they’re babies,” Olson says. She recommends having a foal’s mouth checked around six months to look for any developmental problems, which equine orthodontics or surgery by a veterinarian can possibly correct.

Take-Home Message

Bits are a well-intended means of communication and control of horses, but problems with the rider, the horse, or the equipment can cause pain and even permanent problems for the horse. Correcting any bitting problems early on, from a rider’s hard hands to the horse’s teeth, can help reduce pain caused by bits and leave the lines of communication open between horse and rider.