The oft-overlooked tongue is “a very sensitive organ that experiences heat, pressure, pain and taste,” says veterinarian Dr. Chad Hewlett, the founder and owner of Energy Equine Veterinary Services in Airdrie, Alberta, which specializes in equine sports medicine, treating top-tier horses in both English and Western disciplines. “The equine tongue is made up of twelve different muscles,” he explains. “These muscles are mucosa-covered on the sides and underneath. They are slippery to allow debris to move without getting stuck as they lay against the teeth.”
On the tongue’s dorsal (top) surface are protuberances called papillae. They provide traction to help move food across the mouth and eventually down the esophagus. The lingual frenulum is a membrane that attaches the tongue to the jaw on the lower side. The hyoid apparatus, bones at the back of the jaw, suspend both the tongue and the larynx from the skull. The front section of the tongue is loose and highly mobile.
When relaxed, the tongue lies flat at the bottom of the mouth cavity, resting gently against the roof of the mouth, or hard palate. “The tongue should lay in the center on the lower mandible teeth with the ability to retract and protrude,” says Dr. Hewlett.
The tongue’s primary job is to help the horse eat. Prehension – the act of grasping and moving of feed into the mouth – is the first element of the digestive process. Prehension in the horse involves a combination of lips, incisor (front) teeth and tongue.
“The end [of the tongue] is able to work to decide what the horse wants in its mouth,” says Dr. Hewlett. Then comes mastication or chewing. “Once food is in the mouth, a horse eats in a circular fashion. The papillae help the food stick to the tongue so the horse can press it against the roof of the mouth. This in turn allows the food to be moved over to the teeth where the grinding takes place. The tongue is very involved in this grinding action. The more grinding, the more saliva, which helps with digestion in the stomach.”
When food is thoroughly chopped and/or crushed, a bolus (ball) is formed. A thick area of the tongue starting at the region of the first cheek teeth, called the lingus, pushes the bolus back through a rhythmic muscle action which, in turn, places it in the esophagus for swallowing.
The tongue is also responsible for cleaning the teeth by grabbing leftover food and allowing saliva to wash over their surface.
Equine Tongue Troubles
Tongues are surprisingly susceptible to injuries such as bruising, ulcers, lacerations and punctures, especially the front, mobile section. A rich blood supply, combined with oozing saliva, can sometimes make injuries a gory situation, but more often than not you won’t ever know your horse has a problem. Most injuries are highly treatable and offer a good prognosis.
“Bitting injuries are far and away the most common,” notes Dr. Hewlett. “The tongue is cut or lacerated when extreme pressure or scissoring action occurs.” Poorly-fitting and harsh bits are of course a concern, but even gentle, well-adjusted bits in the hands of a rough rider, or accidents such as a horse stepping on his reins and pulling back forcefully, can cause issues.
Blunt-force trauma from a fall, running into an object, or a kick to the face can cause a horse to bite or hurt his tongue. Foreign objects such as wire, pieces of metal, grass awns (barbed seedheads) and wood splinters can become lodged in the tongue and sharp dental points, edges and caps (baby/deciduous teeth) can also result in painful tongue sores and ulcers. Less dramatically, like humans, horses occasionally nip their own tongue by accident. Regular oral examinations will identify and correct problems before they become major issues.
These symptoms could indicate a horse is experiencing tongue pain or discomfort:
- Dropping feed/hay
- Not eating
- Hyper-salivation
- Bad breath
- Bleeding from the mouth
- Swelling in tongue and/or cheeks
- Standing with head outstretched
- Resistance to the bit or to handling of the head
- Tongue hanging from mouth
- Discolouration (a healthy tongue should be pink and moist)
Certain underlying diseases and infections can trigger tongue-related symptoms. Weakness or paralysis and/or inability to retract the tongue can be the result of a neurologic condition or botulism. Vesicular stomatitis causes lesions on the tongue and other areas of the mouth. And one of the symptoms of a bacterial infection called Actinobacillosis, sometimes known as wooden tongue, may, as the name suggests, lead to a hard tongue, sometimes with sores and swelling.
A veterinarian will diagnose a tongue injury based on clinical signs and an oral examination. Radiographs or ultrasound may also be required. Treatment or resolution of the initial cause of the injury is key. Minor issues will generally heal on their own due to the tongue’s extensive blood supply and saliva flow within the mouth. Anti-inflammatories and antibiotics may be prescribed. Occasionally, surgical removal of foreign objects or suturing is required. Horses are often able to cope with the loss of large chunks of their tongue, using their lips and teeth to help them eat.
While an injury is healing, offer watered-down feeds. If hay stems are causing a problem, try watering down flakes or offer soaked hay cubes or pellets for the interim. Avoid riding with a bit until the injury heals.
Wagging Horse Tongues
In show horses, a tongue that likes to do its own thing can be a quandry for riders. Lolling to the side, sticking out front, flapping – these actions may just be habits, but they can also be the result of stress, ill-fitting tack, and/or physical issues. Regardless, judges usually consider wayward tongues an evasion of the bit and will reflect that in your dressage or hunter score.
Ex-racehorse’s tongues are notorious for not staying put. This is likely due to the prevalence of tongue ties in racing. These straps loop around the tongue and lower jaw to prevent the tongue from getting over the bit and limit the possibility of airway obstruction during heavy exercise. If used incorrectly, they can cause sores, bruising and sometimes permanent numbness, which may result in tongue play long after the horse is retired from the track. Patience and trial-and-error in finding the right bit and other equipment, plus determining ways to maintain the horse’s focus during work, can help the situation over the long term.
Horse Bit Fit Problems
Speaking of bits, the tongue is an important, and often forgotten, element of a correct fit. When a horse is comfortable in the mouth, the tongue muscles relax and the bit is cushioned by and slightly indented into the tongue, relieving pressure on the hard palate. Every horse’s oral conformation is different; therefore finding the correct size and type of mouthpiece for the individual will determine his comfort and happiness at work. For example, horses with thick, meaty tongues (those that bulge from the spaces between the teeth), would probably prefer a thinner bit, perhaps with a gentle port or double-jointed versus a mullen-mouth or a single-jointed snaffle with its nutcracker effect. This allows the bit to ride lower in the mouth, freeing the tongue and promoting normal swallowing and breathing, which contributes to relaxation in both mind and movement.
In fact, resistance through the tongue affects the horse’s entire way of going. The hyoid bones which attach to the back of the tongue and jaw are also connected to a group of muscles extending to the sternum, the shoulders, and the top of the forelegs. From here, the muscles continue to connect to the breastbone, pectoral, and abdominal muscles all the way to the pelvis. A horse carrying the bit comfortably, without tension, will be relaxed from the tip of his tongue all the way to his tail.
