Dental problems can affect any horse at any age

Equine digestion takes place not only in the stomach and intestinal tract, it already begins in the mouth, where the horse chews its feed. Feeds like meadow grass and hay are broken up by the lips, incisors and tongue. The cheek teeth grind the food; particularly roughage, on which horses depend for their nutrition. On one hand chewing mechanically breaks down feed so that it can be swallowed. On the other, it stimulates salivation. The saliva softens the feed and ensures that the pH level in the stomach is buffered. The satisfaction of chewing is also important for the equine psyche. Chewing keeps the horse busy, which is why sufficient roughage should always be available. If this is not the case, the horse will get bored, which leads to stable vices like cribbing and weaving.

A horse that suffers from problems with chewing or dental problems will no longer be able to consume sufficient feed. This leads to subsequent digestive problems and feed not being sufficiently digested. The feed mash cannot be sufficiently saturated by digestive juices if it still in large pieces, and will then not be completely digested.

But how can you tell if a horse has dental problems?

Typical signs include a change of behaviour during eating, refusing certain foods, weight loss, halitosis, excess salivation, headshaking, problems being ridden with a snaffle or curb bit, and discharge from the nose or mouth. If one or more of these symptoms occur, it is urgent that a veterinary surgeon thoroughly examine the horse’s mouth and provide treatment.

The causes of dental problems and issues with chewing are manifold, including congenital anomalies like overbite (parrot mouth) or underbite (sow mouth) and can have a considerable effect on a horse’s nutritional intake and digestion. Such irregularities must be corrected through veterinary dental procedures so that the horse will be able to eat and chew food normally. An abnormal number of teeth can also cause bite problems. Both too many and too few teeth will lead to issues with chewing food and therefore require attention.

Foals and young horse will still have their primary (milk) teeth. Permanent teeth begin to come in when the horse is about one year old; this process lasts until about the fifth year, when the primary teeth are fully replaced by permanent teeth. Eating issues may arise during this time, for example esophageal obstruction (choke). This should be considered when selecting feed, which should be moistened with water if necessary. Choke can be caused not only by dental problems but also from the horse having a tendency to eat too quickly. It is therefore recommended that the feed be moistened with water or oil.

It is also possible for professionals to determine the age of a horse through examination of its teeth. A young horse’s age can be reliably determined from its teeth until it is about six years old. After this, determination of age is somewhat more difficult, so that often a range is given rather than an exact age.

EOTRH (equine odontoclastic tooth resorption and hypercementosis) has been much discussed in recent years; this condition is found primarily in horses aged 15 and older. This disease typically involves the breakdown of the tooth and the formation of cementum near the roots. These changes mainly affect the incisors and anterior cheek teeth. The cause of this disease appears to be increased mechanical stress on the periodontium and the associated inflammatory processes caused by penetrating bacteria. An affected horse will often have an unpleasant odour coming from the mouth, and recessed and bulging gums. Since EOTRH can be very painful for the horse, it must receive veterinary treatment which may include the removal of the affected teeth.

A particular characteristic of equine teeth is their reserves for dental abrasion. A medium-sized horse’s teeth will have reserves of about six centimetres on average. The selenodont cheek teeth are regularly worn down from chewing food. However, uneven wear from long feeding breaks and little roughage consumption can cause the cheek teeth to form ‘hooks’. These formations are recognizable by a so-called bilateral scissor bite if present on the outside in the upper jaw and on the inside of the cheek teeth in the lower jaw. Such hook formations can lead to painful injuries to mucous membranes and interference with the eating and breaking down of solid foods. To avoid such problems, it is recommended that the horse’s teeth be examined regularly once a year and given corrective treatment, if necessary.

However, the incisors can also be excessively worn down, for example by behavioural problems such as cribbing and wood-chewing. But the incisors can be considerably worn down even when a grazing muzzle with hard plastic inserts is worn. The incisors of horses that wear such grazing muzzles should therefore be checked regularly. It is also important, including for the horse’s psychological well-being, that such grazing muzzles are only worn for a few hours at a time.

However there are other dental diseases seen in horses. Dental caries, for example, can occur in horses as well as in humans. This is mostly caused by sticky feeds that are high in starch and sugar. If the caries spreads, it may infect the roots of the teeth. Other reasons for root inflammation include a trauma or tooth fracture and associated inflammation, or a pathogen infection of the surrounding tissue. One can recognise affected horses primarily through problems with eating. Pusty discharge from one nostril may also occur if the pathogens migrate from the root of the tooth into the paranasal sinus and cause sinusitis there.

An inevitable age-related tooth abrasion in older horses stems from the depletion of tooth reserves. The result is that the affected horse will no longer be able to sufficiently break up its hay with its cheek teeth. Typical signs include weight loss, quidding and fibrous faeces. If oats are fed to the horse in the form of whole oat grains, these will often be found undigested in its excrement. The affected horses must be fed a suitable hay substitute such as Pre Alpin® Wiesencobs, Pre Alpin® Wiesenflakes or Pre Alpin® Senior in sufficient quantities to compensate for the lack of roughage, as otherwise they will quite literally starve. However, even with concentrated feeds it is important that the grain is hydrothermally processed and easily digestible.  This may include crush oats, oat flakes, barley flakes or maize flakes. Alternatively you can also feed your horse soaked Luzernecobs, Maiscobs or in combination, as Kraftpaket. Senior horses can also be fed AlpenGrün Mash on a daily basis as a cereal-free alternative. More energy can be supplied through the addition of oils (e.g. linseed oil).

However, horses with teeth and chewing problems will also require changes to their keeping and management in order to allow for stress-free eating. Because when horses are kept together in groups, it’s frequently the old and sick horses that are pushed away from feeding stations by their younger counterparts.
Dr. med. vet. Katharina Boes
November 2016 ©AGROBS GmbH
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(* The references refer to the technical content of the text and not to the product recommendations.)