What is EOTRH and How Does it Affect Horses

What is EOTRH and How Does it Affect Horses

Health & Safety

Getting your horse's teeth checked at least twice a year is essential and this needs to be done by a qualified equine dentist. If a horse has any pain in their mouths it can lead to all sorts of health issues and even prevent them from wanting to eat or drink, not to mention the fact that placing a bit in their mouths might sit on a painful tooth causing even more discomfort.

Horse's often develop sharp points on their cheek teeth (molars) and when this happens affected teeth need to be filed down. However, their front teeth which are the incisors and canines, can be the cause of dental pain too which is something a dentist needs to check out when they give your horse's mouth the once over.

Equine odontoclastic tooth resorption and hypercementosis or EOTRH is a relatively newly identified dental condition and it is extremely painful for a horse to have to cope with, but it is not a new disease.

Only Recently Identified

The reason why the condition has only recently come to light is because horse's tend to live that much longer these days due to better nutrition and veterinary medicine. As such vets and dentists are looking more closely at horse's mouths. EOTRH is a disease that affects the older horse and it's when both the tissue and the bone around an incisor and canine root is reabsorbed into their bodies.

When a horse suffers from the condition, they lose a lot of the gum found between each tooth whether it's an incisor or a canine. Food then starts to build up in these gaps which is the perfect environment for an infection to take hold. The result is that teeth become loose as the periodontal ligament and the alveolar bone around each affected tooth is destroyed.

As the condition progresses, the inflammation worsens causing a lot of pain and discomfort to the horse. Not only this, but as things deteriorate around an affected tooth, the weaker areas are more prone to fractures causing even more pain which in turn affects horses in many ways which are as follows:

  • A reluctance to eat or drink any water due to the pain
  • A change in attitude and behaviour again due to the fact they are in pain
  • A reluctance to have a bit placed in their mouths
  • A reluctance to have their teeth examined

As yet, vets are not sure why the condition rears its ugly head in the older horse although some studies have shown that it could be age-related. As horses get older they experience changes in their mouths. Other reasons could include the fact a horse does not chew their food enough or they may have received some sort of trauma to their mouths which triggers the start of the condition.

When a horse lowers their head to graze, their incisors are bathed in saliva which is a natural process that helps move both the food and bacteria around in their mouths. If a horse does not chew enough when they are out at grass, it tends to stay in their mouths too long and therefore begins to stagnate which could cause EOTRH to develop. However, other studies have suggested that chewing food puts a lot of strain on a horse's canines and incisors which as a result can cause the condition to develop in the older horse. Lastly, some research suggests that bacteria found in a horse's mouth might be responsible for the condition developing.

What Horses are More at Risk?

EOTRH tends to affect horses over the age of fifteen with Thoroughbreds and Warmbloods being at the top of the list with Arabs being closely behind. Studies have shown that stallions could be more prone to the condition than geldings or mares.

Horses that are allowed out onto limited pasture are also at greater risk due to the fact they don't have to chew their hard feed as much as they would if they were on a alfalfa based diet. Any horse with a history of an endocrine condition like Cushing's disease or equine metabolic syndrome are more susceptible to developing the condition too. The reason being that horses with more insulin and glucose circulating around their bodies might be responsible for EOTRH developing.

Signs to Watch Out For

It can take years for the condition to develop which makes it difficult to pick up on any early signs. However, if you notice that your horse has difficulty or shows a reluctance to bite on a hard treat like a carrot or even an apple, it could be a sign of EOTRH. A horse will attempt to use their lips rather than their teeth to grasp the treat.

Horses with the condition may also spend more time mouthing at their water buckets rather than drinking from them. They may also show resistance to the bit and hyper-salivate much more than usual. Weight loss is another sign that a horse might not be eating enough due to the fact it is too painful for them to chew on grass or any hay they are being fed. Lastly, a horse with the condition might show a real reluctance to have their teeth examined.

Can Anything be Done

Sadly, not a lot can be done for a horse once the condition has taken hold. However, regular dental check-ups are essential because a qualified dentist would be able to identify there is a problem and may recommend you do the following things:

  • To flush your horse's mouth out on a daily basis to get rid of any feed material left between their teeth
  • To use an antibiotic treatment as a way to reduce the amount of bacteria that builds up in your horse's mouth which in turn limits the risk of a local infection taking hold

With this said, if the condition is in its advanced stages, the dentist would recommend removing affected teeth which relieves the pain and discomfort a horse is feeling. This could also help prevent the condition from affecting other teeth. The thing to bear in mind, is that horses cope very well when incisors or canines have to be removed.


Although EOTRH has only recently been identified as a real problem for the older horse to have to cope with, a lot of research is taking place into the condition which means more is known about it and how it develops as time goes by. If you have any concerns about your horse, you should discuss your worries with a vet and have your horse's mouth examined by a qualified equine dentist sooner rather than later so that your horse is made more comfortable as quickly as possible.



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