Bits: Protect Your Horse's Mouth
- Oct 1, 1998
The bit should rest comfortably in the horse's mouth, whether the reins are slack or taut.
A simple metal shape--and a complex tool of communication between horse and rider. Inside the horse's mouth, the bit's motion sends messages to the horse. The message can be as subtle as a twinge, obvious only to the horse. Or, a harsher sensation can result in the animal's gaping mouth and visible pain.
The bit is a control device, a piece of equipment accepted as essential. Riders think about putting a bit on a horse, while a more humane approach focuses on inviting the horse to respond to the bit.
To the horse, the metal appliance is a foreign object inserted in a small space in his mouth. The bit's movement stimulates a response in the horse's body: immobile, forward, backward, left, or right. The design affects action, and the art of bitting matches the horse with the most comfortable bit.
Effective Yet Humane
The mouthpiece of the bit rests on the horse's tongue. Through training, the horse learns to respond to sensations in his mouth. A feeling that begins on the tongue results in how the horse places his feet.
The bit in a bridle helps you direct the horse's orientation, speed, and attitude. A bit's action influences the horse through pressure, on the bones of the jaw (mandibles) and the tissues of tongue, cheeks, and lips. The horse has a strong jaw and pliable mouth. To evade bit pressure, he can try to move his jaw in a circle, or reposition his strong, muscular tongue and mobile lips.
Most bits act primarily on the tongue. R. Clay Stubbs, DVM, Johnson City, Texas, noted, "If you put pressure on the tongue, the horse's response is to move the tongue. The most critical location for pain in the performance horse is at the very base of the tongue, primarily over the third molars. When the horse flexes at the poll, there's no way that he can keep his tongue from moving against those back teeth." Stubbs, who focuses on relieving oral pain through equine dentistry, noted that this area is about 12 inches from the front of the horse's mouth.
A restricted tongue affects more than the horse's mouth. Joyce Harman, DVM, Washington, Va., explained how the tongue is attached to the hyoid bones, lying between the mandibles. "The hyoid apparatus is like a little sling of bones starting up near the temporomandibular joint (TMJ). Like half of a rectangle, it goes straight down the mandible, across the bottom, and up the other side. Imagine a sling to keep the tongue from falling out the bottom of the throat. Muscles attach the tongue to those bones, and muscles from those bones go up to the TMJ and down to the sternum." Harman noted that a bit that restrains the tongue's freedom can "lock up" the TMJ.
An abnormal bite can cause soreness of the TMJ. Stubbs explained, "The TMJ is a hinged joint, flat like a hinge, and a loose hinge. The TMJ can become inflamed and sore, like any other joint in the body. "If you have a sore TMJ, you have another source of pain."
When a bit interferes with the horse's normal use of the tongue, it inhibits the horse's freedom to swallow. Like a human, the horse draws up his tongue to the palate to swallow. The bit's pressing into the tongue restricts the tongue's movement.
Horses vary in the number of times they swallow while being ridden, and the amount of saliva produced. "The horse is an eater of dry matter," explained Harman. "He has to produce a lot of saliva to make dry hay wet in order to swallow it."
The bit influences other pressure points on the horse's head. A bit with an extremely high port, such as a cathedral bit, can touch the hard palate. The lever action of a curb bit applies pressure on the poll, as the bridle's crownpiece presses down toward the mouth.
Your pulling the reins can cause the horse pain. Stubbs noted that horses tolerate mouth pain differently, and this difference hinders interpretation of the extent of pressure or injury. He said, "Horses are somewhat less sensitive to mouth pain than humans are. The tongue is not as sensitive as ours, or the species would not have survived.
"But with some horses, you reach a point where the pain is enough that the horse pushes against the painful stimuli. It's like he gets so mad that he pushes against what's hurting."
Whatever the bit, your hands intensify or reduce pressure and pain. If used roughly, even the "mildest" design can injure a horse's tongue, lips, or bars (the tissue over the mandible, in the space between molars and incisors).
Stubbs said, "Most bits are made so they don't put pressure on the horse until you start pulling on them. You could put almost anything in the horse's mouth if you didn't pull on it."
Riders and trainers can choose among hundreds of models of bits across the disciplines. Many search for a bit that will cure all training problems. That "magic" bit doesn't exist.
A bit's design affects how it shifts its angle within the horse's mouth. The bit's mouthpiece moves up or down, forward or back, or left or right, to apply and release pressure (Some curb bits with long, swept-back shanks will apply a slight pressure continuously, even when reins lie slack.)
Bits fall into three major categories--snaffle, curb, or a combination. The snaffle is usually a jointed bit, with two cannons meeting at the joint. When the rider pulls the reins, the joint presses into the tongue to produce a "nutcracker" action on the jawbones. The bit also applies pressure on the corners of the mouth and the lips.
Snaffle mouthpieces range from the mild straight bar type to the rougher, twisted wire models. Popular styles are the loose-ring, D-ring, eggbutt, and full cheeked. With a double or full bridle, the snaffle (or bradoon) has smaller rings, so both curb and snaffle can operate independently.
Another version, the gag bit, adds pressure on the poll. Special bridle cheeks slide through the bit rings to create a pulley effect.
The curb bit acts with leverage. Its mouthpiece is attached to cheeks (also called shanks) for a double bridle, or curved cheeks for a Western or Walking Horse bridle. As you adjust the reins to feel contact with the horse's mouth, the bit shanks move toward the horse's chest in a 45-degree angle. The lever presses on the tongue and bars, as the curb chain acts as a fulcrum on the jawbones.
The length of cheek above and below the mouthpiece determines the curb's severity. A curb's ratio, or the comparison between the two lengths, calculates its action. A 6:1 ratio means the cheek below the mouthpiece is six inches, with one inch above.
Most curbs have a port, a slight arch in the middle of the mouthpiece. A straight mouthpiece can be more severe, especially with a long shank.
In either snaffle or curb, a thinner mouthpiece tends to increase severity. A thicker diameter can spread pressure over a larger area.
Styles like the Pelham and Kimberwick combine the curb and snaffle actions. Many trainers claim that these hybrids don't succeed in a clear communication, but some horses go best in one of these models.
The Pelham has four bit rings. Reins attached to the curb shank affect the bars; the snaffle reins press against bars, tongue, and lips. The Kimberwick resembles a D-ring snaffle, except it has a ported curb mouthpiece and a low ratio of leverage. Both types use curb chains.
Accessories enhance the bit's function. A curb chain is a standard accessory for curb, Pelham, and Kimberwick bits. Some horses go better with a leather strap, or a leather or rubber cover over the chain. A leather lip strap, added to a curb or Pelham with a straight shank, prevents the horse from lipping the shank.
Choosing the right bit design depends on your needs and specific goals. If you plan to show in a specific discipline, confirm that the bit meets current association rules and the unwritten rules of show ring fashion. Ideally, you consider the horse, and how the bit will communicate with comfort.
Comfort, Not Resistance
Horses vary in their tolerance of a bit. Stubbs explained, "There's a tremendous difference from horse to horse, depending on what mouth problems they have and what's painful to them. I have observed that some performance horses can tolerate a tremendous amount of pain when they're under the influence of adrenaline. When they're in training at home and in a familiar place, that's probably different."
Bits cause resistance, and you have observed how horses try to avoid pain. To evade the pressure of a snaffle bit, a horse might open his mouth and cross his jaws. He might attempt to grab the bit in the premolars, so your response could be to add a restricting noseband that prevents him from opening his mouth very wide.
Other ways horses express mouth pain are flapping the lower lip, tilting the head, and raising the tongue over the bit. Such instances are seen in the show ring, even at the level of the Olympic Games.
To improve the horse's comfort, bit makers offer new, horse-friendly designs. Harman named the bit used by Linda Tellington-Jones: "You see play in the joints. The bit has sidepieces on a joint, so there is a little give to the bit. The more play you have in a bit, the more the horse can pick up your subtle signals."
Harman also praised bits designed by Myler's, Inc. of Marshfield, Mo. Ron and Dale Myler have developed models of Western bits for three stages of training, in a progression toward total freedom of the tongue. The bits have curved mouthpieces that rotate independently, so you can isolate your signal to the left or right.
The youngster starts in a two-jointed snaffle, where three pieces lie flat across the tongue to produce a softer tongue pressure than a single joint. Dale Myler said, "We train more off the horse's tongue rather than the bars, in the first two stages, to keep the bars in shape for a finished bit. The bit collapses in the corners of the bars and takes the horse's tongue away."
The second stage bit puts an even pressure across bars and tongue, and controls the amount of tongue over the bars. The horse has freedom to swallow, and the bit has no pinching action. A mouthpiece like a mullen barrel or mullen hinge allows you to ride on a slack rein. You give the horse the opportunity to carry himself--you can make a correction, then again pitch the reins to the horse.
Of the bit for a finished horse, Myler said, "You take a horse as soft as he will allow you to." The horse has progressed to the easiest bit in models that include a ported barrel.
The progression from firmer to softer bit allows you to signal positively and avoid resistance. Myler advised to listen to the horse. "When he resists, he tries to tell you something. Many people will make a mistake, of once they get resistance in a snaffle, they go to a twisted wire snaffle. Then when they get resistance in the twisted wire, they go to a double twisted wire. They punish the horse for being better broke, so they get into face fights."
Whether snaffle or curb, the ported mouthpiece seems more acceptable to the horse. A straight bar curb presses down on the tongue, directly to the bars.
Stubbs noted, "The ported bit has tongue relief. The horse can move the tongue and change the shape of the tongue. He can slide his tongue under the port."
Horsemen have perpetuated the belief that a high port injures the horse, yet bit makers explain that most ports rest over the tongue without touching the hard palate. Harman cited the ported curb design for helping horses relax and move more comfortably. "I first learned that the curb is often a milder bit, and now I know why. How many horses go from a snaffle to a full bridle, and now you can ride them? Those bits have at least a small port, and the bar of the curb protects the tongue from the driving down of the snaffle. You distribute pressure around to protect the tongue."
Equine dentists have performed the "bit seat," on the first upper jaw teeth for many years. Stubbs believes that sculpting the bit seat is even more important on the lower jaw. "When a horse is flexed at the poll, most of the bit pressure goes to the lower jaw. The tongue is pulled backward away from the upper teeth. At the same time, the bit pressure can push the cheeks into those upper jaw teething the area where these teeth are the sharpest and most damaging. The upper teeth cause more cheek problems, because the upper jaw is much wider than the lower."
The result is sore cheeks, especially at the corners of the mouth. Lesions indicate that the bit exerts too much pressure.
Stubbs described the pressure of the jointed bit as making the tongue into a triangular shape, with the potential of exerting severe force on the lower jawbones. He said, "The jointed bit bends in the middle and wraps around the lower jawbone. When the horse's nose is pointed toward the ground and you pull back on both reins, much of that pressure goes to the lower jawbones."
His approach to dentistry is first to make the horse comfortable in the mouth. "If the horse fights the bit from the pain it causes, the teeth can be causing the pain. If the teeth are fixed, you've got a better horse."
He specifically aims to remove points on the third molars, both upper and lower, while smoothing every tooth in the horse's mouth. When the horse moves the jaw, the masseter muscles push the cheeks against those upper back molars. The tongue moves and rubs against the inside of the lower teeth.
About wolf teeth (first premolars), Stubbs explained, "When the horse holds his head down with nose tucked, the bit pulls away from the wolf teeth. The tissues never touch the wolf teeth because of the bit." He believes the wolf teeth should be removed, but he has questioned the wisdom about needing to remove the wolf teeth, saying that little scientific work has been done on dentistry and the bit. In his view, the main reason for removing wolf teeth is to allow the dentist to smooth and sculpt the first large upper jaw tooth.
Matching Bit To Horse
A variety of factors influence a bit's acceptance by the horse. First, the bit must fit--mouthpiece and the bit's heft should match the width, depth, and angle of the horse's mouth. The typical tongue is about an inch thick, with some tongues thinner or thicker.
Bits' widths measure from four to 5 1/2 inches. The bit should hang evenly in the horse's mouth, without rubbing the horse's lips or cheeks. A curb fits snugly against the corners of the mouth. A snaffle should create one wrinkle at each corner.
A quality bit has a smooth finish on all edges and joints. Generally, a hand-buffed and polished bit indicates craftsmanship. Both sides of a bit must match in size and angles.
Today most bits are made of stainless steel, fabricated in North America, Germany, England, or Korea. What matters to the horse is the material in the mouthpiece-metal, or metal covered with rubber or a tough nylon.
A horse could resist a bad-tasting bit, although even the experts aren't sure what horses prefer. Materials do vary in taste, and bit makers offer mouthpieces of "sweet iron," or even ones saturated with special flavors. Copper is a popular option, as it tends to increase the horse's salivation.
Stubbs noted that with less salivation, the horse is more likely to suffer from mouth pain. He added that a horse with a sore tongue might drink less water, as water washes away the saliva and the tongue hurts more. In the summer, a sore-tongued horse can dehydrate and possibly colic due to not drinking enough water.
A bit's heft and weight affect its balance. The bit should rest comfortably in the horse's mouth, whether the reins are slack or taut with gentle contact. With an unjointed bit, some experts recommend to hold it in the palm of the hand to observe how it naturally hangs.
You also can test a curb's balance this way: hold the mouthpiece on the tips of your forefinger and little finger, to simulate the bars of the horse's mouth. Swing the bit back and forth--look for a well-balanced bit to swing for a long time before returning to its original position.
A bit with joints has to find balance through how the horse carries the device. How the horse balances the bit in his mouth can change with pressure of headstall and reins.
A bit can "talk" or listen gently, according to your hands. Myler said, "Bitting is not a science--it's to find the mouthpiece that the horse can relax into the hands that are holding onto it. If a horse is relaxed, watch your hands. If you lift your hands, your horse will follow your hands."
About the Author
Award-winning writer Charlene Strickland lives in Bosque Farms, N.M. She has published 8 books and over 600 magazine articles, and is a member of the International Alliance of Equestrian Journalists.
POLL: University Equine Hospitals