The tongue has an excellent blood supply and will bleed profusely in the event of injury. Unless the lingual artery is cut, however, which can lead to major haemorrhage, blood is often swallowed and signs are missed.
Frequently a horse may appear to carry on as normal and even quite severe injuries may go undetected.
The bit is by far the most common cause of tongue injury, perhaps through harsh rein action or because the horse is tied by or tangled in the reins and pulls back.
He may accidentally bite his tongue if he falls or suffers a blow or kick that causes him to close his teeth onto it.
He may also suffer lacerations from a sharp object while browsing, or a superficial (but often very sore) cut if his tongue rubs against a sharp tooth. This can cause chronic ulceration and pain, particularly if the bit is holding the tongue down against the sharp edge.
Foreign bodies such as thorns, twigs and the awns of some wild grasses can become lodged in the tongue and cause sores and abscesses. Younger horses and foals in particular tend to be “mouthy”, nibbling and chewing on things they shouldn’t. Check hay for foreign objects and clear away any debris at the yard, especially around feeders, to help prevent injury.
Holding a horse’s tongue can help immobilise his head and keep his mouth open for an examination. If he pulls away, however, he may bite his tongue. There’s also the risk that the pulling force will potentially cause damage to nerves or other structures.
The risk is lessened if the handler holds the halter along with the tongue, as the handler will go with the horse if he pulls. With the availability of reliable oral and injectable sedatives, however, a gag is a more satisfactory means of carrying out an examination, and safer for both horse and handler.
A cut tongue can be difficult to suture (stitch) and the wound often breaks down. The tongue can’t be immobilised by bandaging, like a foot or a limb, so constant movement combined with bathing in saliva can break open the suture knots.
Fortunately, because of its fantastic blood supply, most wounds to the tongue heal well. It is almost always worthwhile attempting a surgical repair, even if this is difficult because of the long, narrow mouth.
Pain may affect the horse’s ability to eat, so consider altering his diet while the wound heals. Choose foods that are easy to chew and swallow, perhaps wetting his hay and feed or switching to hay cubes or softer forage.
It is also a good idea to avoid using a bit during recovery. Even a wound that heals well can leave a prominent scar that affects how a horse responds to a bit, especially if the injury is in the bit path.
A tongue injury can cause neural damage, which may have long-lasting repercussions, perhaps making the horse head-shy and/or influencing his reaction to the bit.
Horses usually cope well even if a portion of the tongue is lost, eating and working normally, provided the missing part is in front of the frenulum (an area that comprises approximately 20% of the organ).
However, as the tongue holds the bit in place and prevents it from moving around in the mouth, losing a large part of the tongue may affect the horse’s performance in a certain discipline. Such an injury could be career-ending for a dressage horse, but not for a horse that performs in a bitless bridle.
How the tongue works
The horse’s tongue is made up of more than a dozen different muscles and is a highly specialised working tool.
● The mobile front section works together with the teeth and lips to select and pick up feed or nip off blades of grass.
● Horses are terrific nibblers and adept at eating only the choicest bits of food, as anyone who has ever found a medication or supplement left neatly in the bucket after the rest of the feed has been cleaned up will know.
● The frenulum, where the tongue starts to attach to the underlying tissue, plays a vital role in chewing and swallowing.
● Specialised protuberances called papillae, which cover the entire upper surface of the tongue, help guide food into position before it is pressed up against the ridged roof of the mouth.
● This serves to force the food onto the chewing surfaces of the teeth, where it is ground and passed across the tongue again, and towards the rear of the oral cavity in a spiral motion.
● Lastly, the now thoroughly pulped food encounters a thickened area of the tongue called the lingus, which pushes it back for swallowing.
● Despite being covered by a thick membrane (mucosa), the tongue is an extremely sensitive organ and detects pain, heat, pressure and taste.
● It also plays an important part in keeping the teeth clean, as the horse moves it around to dislodge remnants of food.
Ref: Horse & Hound; 16 April 2015