Oral lesions in equines

WE have looked at how a bit and bridle can impact your horse’s performance, but what about your horse’s oral health? Every horse is different and, as most bridles are sold as pony, cob or full sized, it is increasingly difficult to find a bridle to fit correctly and comfortably, which can result in oral lesions.

The most common site for oral lesions or ulcers are the inside of the cheeks and the corners of the lips. Lesions of the soft tissue inside the cheeks occur when the loose cheek tissue rubs against or is accidentally bitten by the horse’s molar teeth. As the upper molars develop sharp enamel points on their outer edges, these are liable to rub against the cheek and cause ulceration, especially with ill-fitting tack.

Having a tight noseband can compress the cheeks, increasing the likelihood that the teeth will injure the soft tissue. The type of noseband and the position can impact the severity of the lesions.

A cavesson noseband, the upper strap of the crossed noseband or the Micklem bridle encircles the head directly over the premolars (first three cheek teeth). When these straps are tightened, the cheeks are pressed firmly against the teeth, which adds to the likelihood of abrasions. Generally, a drop noseband, a flash or the lower strap of a Micklem or grackle bridle, fit in front of the premolar teeth and lessen the squeeze on the cheeks against these teeth.

The traditional guidelines on fitting a bridle are that a recommendation of a two-finger space is left between the bridle and the horse’s face. This is to allow the horse to comfortably open and close its mouth, promoting relaxation through the jaw. When a noseband is over-tightened, horses do not get relief from the pressure, causing tension and tightness.

The areas of highest pressure under the noseband are the edges of the nasal bones and under the jaw, where the noseband crosses the mandible. High pressure can also be applied to these areas when using bitless bridles.

In a study of Icelandic horses, lesions around the corners of the lips were associated specifically with the use of a loose ring snaffle bit, especially if the mouthpiece was either too wide or too narrow for the size of the horse’s mouth. In another recent study of Danish sport horses, who were examined during competitions, revealed that 9% of horses had oral lesions or nips on the inside corner of the lips.

The best way to reduce the risk of oral lesions in horses is to firstly ensure they are having regular dental care. A good dental professional can help a horse owner to understand the conformation of the horse’s mouth and help ensure the horse is on the correct dental schedule to allow preventive measures of very sharp enamel points. Also taking care that tack and equipment, especially the bit and noseband, are correctly fitted and adjusted.