EOTRH in Horses: Signs, Diagnosis, and Treatment

By Dr Duncan Houston

EOTRH is one of the most painful dental diseases seen in older horses, but it is also one of the easiest to miss in the early stages. A horse may still eat, still come to the fence, and still look “mostly normal,” while quietly avoiding anything that makes the front teeth hurt.

That is why owners often first notice small changes: refusing carrots, dropping feed, salivating more than usual, resisting the bit, grazing less effectively, or losing weight without an obvious reason.

The important point is this: EOTRH is not just an old-horse cosmetic tooth problem. It is a progressive dental disease that can cause real chronic pain. Early recognition, dental radiographs, and the right treatment plan can make a major difference to comfort and quality of life.

Quick Answer

EOTRH, short for equine odontoclastic tooth resorption and hypercementosis, is a progressive dental disease that mainly affects the incisors and canine teeth of older horses. It causes destruction of tooth structure, abnormal cementum buildup around the roots, inflammation, infection, and pain. Dental radiographs are essential because the most serious disease is often hidden below the gumline. In advanced or painful cases, extraction of the affected teeth is usually the only treatment that gives lasting relief. (Center for Equine Health)

What Is EOTRH in Horses?

EOTRH stands for equine odontoclastic tooth resorption and hypercementosis.

That sounds like a mouthful because it is. In plain terms, it means two damaging processes are happening around the teeth:

Tooth resorption: the body starts breaking down parts of the tooth structure.

Hypercementosis: abnormal cementum, a hard tooth-supporting material, builds up around the tooth root.

Together, these changes can make the tooth roots thickened, distorted, unstable, infected, and painful. UC Davis describes EOTRH as a progressive condition in middle-aged and older equines that predominantly affects the incisors, although canine teeth and occasionally premolars can also be involved. (Center for Equine Health)

The incisors are the front teeth horses use to bite grass, take treats, and grasp some feed. This is why EOTRH can interfere with grazing, even when the cheek teeth at the back of the mouth are still able to grind food.

In practice, one of the biggest problems with EOTRH is that the visible part of the tooth may not show the full extent of disease. A horse can have significant root changes, infection, and pain below the gumline before the incisors look obviously abnormal from the outside.

Why Does EOTRH Happen?

The exact cause of EOTRH is still not fully understood. Current evidence suggests it is likely multifactorial rather than caused by one single problem.

Possible contributing factors include:

• Age-related dental changes

• Mechanical stress on the incisors

• Periodontal disease

• Bacteria or other microorganisms in the mouth

• Reduced grazing or altered feeding patterns

• Concurrent health conditions such as PPID

• Genetics

• Previous trauma or excessive dental procedures

UC Davis notes that a definitive cause has not been determined and lists several possible contributing factors, including microorganisms, environmental influences, limited grazing, periodontal disease, concurrent health issues, feed type, trauma, and genetics. (Center for Equine Health)

The practical takeaway is simple: this is not usually something an owner has “caused.” It is a progressive disease seen mainly in older horses, and the focus should be on recognizing pain, confirming the diagnosis, and managing the horse properly.

Which Horses Are Most at Risk?

EOTRH is mainly a disease of older horses.

It is most commonly seen in horses over 15 years of age, although mild cases can be seen younger. UC Davis notes that Thoroughbreds and Warmbloods over 15 make up about half of reported cases, but horses of any breed and sex can be affected. Cases have been reported in horses as young as 10. (Center for Equine Health)

Virginia Tech also describes EOTRH as primarily affecting horses over 15 years old, with Thoroughbreds and Warmbloods more commonly represented, although other breeds can be affected. (VetMed EMC)

Higher-risk horses include:

• Senior horses over 15

• Horses with previous dental disease

• Horses with periodontal disease around the incisors

• Horses with difficulty grazing

• Horses with unexplained weight loss

• Horses with PPID or other age-related health conditions

• Horses that resist biting, bridling, or mouth handling

The mistake I see most often is assuming that a senior horse is losing weight because they are “just old.” Age may be part of the picture, but pain, poor chewing, PPID, dental disease, parasites, arthritis, and herd stress all need to be considered.

Why EOTRH Is Often Missed Early

EOTRH develops gradually. Horses are also very good at adapting to chronic discomfort.

A horse with early EOTRH may not stop eating completely. Instead, they may change how they eat. They may become slower, pickier, or more reluctant to bite into firm objects. Because this happens over months or years, owners may not notice until the disease is advanced.

Early signs can be subtle:

• Refusing carrots, apples, or hard treats

• Taking treats carefully instead of biting firmly

• Pulling away when the incisors are touched

• Mild gum redness

• Slight gum recession

• Small amounts of feed packed between the incisors

• Mild bad breath

• Reduced grazing efficiency

• Slight change in attitude when bridled

UC Davis notes that horses may not show clinical signs in the early stages, and that owners may not recognize the disease until it becomes painful because the onset is gradual. (Center for Equine Health)

This is why incisor checks matter. A routine float that focuses only on the cheek teeth can miss an important front-of-mouth problem.

Signs of EOTRH in Horses

EOTRH signs can range from subtle to severe. The most useful signs are often changes in how the horse bites, grazes, accepts the bit, or reacts to mouth handling.

Common signs include:

• Reluctance to bite carrots, apples, or treats

• Dropping feed

• Quidding or dropping partially chewed material

• Increased salivation

• Bad breath

• Difficulty grazing

• Reduced appetite

• Weight loss

• Head shaking

• Resistance to the bit

• Reluctance to be bridled

• Head shyness

• Irritability or dullness

• Bleeding around the gumline

• Gum swelling

• Gum recession

• Loose incisors

• Fractured incisors

• Draining tracts or small pimple-like lesions above the teeth

• Tooth discoloration

• Bulbous swelling around the tooth roots

UC Davis lists difficulty chewing, bad breath, drooling, head shaking, quidding, weight loss, tooth fractures, painful swollen gums, ulcerations, draining tracts, and bulbous changes around affected teeth as possible signs of EOTRH. (Center for Equine Health)

Merck Veterinary Manual describes severe EOTRH signs as gum recession, incisor gingivitis, draining tracts, tooth crown fractures, and discomfort when the incisors are manipulated. (Merck Veterinary Manual)

A useful owner checkpoint:

If your older horse suddenly refuses hard treats, resists having the mouth handled, or struggles to graze, do not assume they are being fussy. Treat it as possible dental pain until proven otherwise.

What Does EOTRH Pain Look Like?

EOTRH pain is often underestimated because horses do not always show pain dramatically.

Some horses keep eating because they are hungry, not because they are comfortable. Others avoid specific actions that hurt, such as biting down with the front teeth. That is why a horse may eat soaked feed but refuse carrots, or nibble hay but avoid grazing.

Signs that suggest incisor pain include:

• Pulling away when the front teeth are touched

• Refusing to bite treats

• Holding feed awkwardly in the lips

• Eating more slowly

• Taking longer to finish meals

• Resisting the bit or noseband

• Head tossing when ridden

• Sudden change in temperament

• Standing at pasture without actually grazing well

The real concern is not just the presence of abnormal teeth. It is whether the horse is painful, losing weight, developing infection, or struggling to eat enough.

How Serious Is EOTRH?

EOTRH is progressive, but not every horse is at the same stage when it is diagnosed. A severity framework helps owners understand what level of response is needed.

Severity level	What it may look like	What it may mean	What to do
Mild	Slight gum redness, mild tooth discoloration, still eating well, no weight loss	Early or suspected EOTRH, or another mild incisor problem	Book a veterinary dental exam. Ask whether radiographs are appropriate. Monitor eating and grazing closely
Moderate	Refusing carrots, dropping feed, mild quidding, gum recession, bad breath, reduced grazing	Painful incisor disease, periodontal disease, early infection, progressing EOTRH	Arrange a veterinary dental exam soon. Radiographs are strongly recommended
Severe	Loose or fractured incisors, draining tracts, swollen painful gums, weight loss, obvious discomfort	Advanced EOTRH, infection, tooth instability, significant pain	Prompt veterinary dental assessment and radiographs. Extraction may be needed
Urgent	Sudden inability to eat, severe facial swelling, fever, heavy bleeding, choke signs, colic signs, severe depression	Serious dental infection, trauma, choke, systemic illness, or another urgent condition	Seek urgent veterinary care

The key decision point is this:

Mild cosmetic changes can wait for a scheduled dental visit. Pain, weight loss, loose teeth, swelling, draining tracts, or inability to eat should not wait.

When Is EOTRH an Emergency?

EOTRH itself is usually a chronic condition, but complications can become urgent.

Call a vet promptly if your horse has:

• Sudden inability to eat or drink

• Rapid weight loss

• Severe mouth pain

• Loose, fractured, or bleeding incisors

• Facial swelling

• Fever

• Foul smell from the mouth

• Pus or draining tracts around the teeth

• Severe one-sided nasal discharge

• Signs of choke

• Signs of colic

• Marked dullness or distress

Choke signs include coughing, repeated swallowing, drooling, stretching the neck, feed or saliva coming from the nostrils, and anxiety around eating. A horse with poor dentition or painful incisors may be at higher risk if feed is not chewed properly.

Do not syringe water, oil, or feed into a choking horse. Remove feed, keep the horse calm, and call your vet.

How Is EOTRH Diagnosed?

A proper EOTRH diagnosis requires more than looking at the front teeth.

Your vet will usually combine:

• The horse’s age and history

• Changes in eating, grazing, weight, and behaviour

• Oral examination

• Incisor and gum inspection

• Assessment for loose, fractured, infected, or painful teeth

• Dental radiographs

• Sometimes CT imaging in complex cases

Dental radiographs are especially important because EOTRH affects the roots and surrounding bone. The visible crown of the tooth may not show how much disease is present below the gumline.

UC Davis states that EOTRH is diagnosed using a combination of veterinary dental examination, patient history, and radiographs. Radiographic changes can be graded by severity. (Center for Equine Health)

Merck Veterinary Manual is even more direct: diagnosis and disease staging depend on radiographic evaluation. (Merck Veterinary Manual)

In practice, radiographs help answer the questions that matter most:

• Which teeth are affected?

• How severe is the resorption?

• Is there hypercementosis around the roots?

• Is there bone loss?

• Are there abscesses or draining tracts?

• Are teeth loose or structurally weakened?

• Should treatment be conservative, staged, or surgical?

• If extraction is needed, how many teeth should be removed?

Without radiographs, treatment planning is partly guesswork.

Why a Normal-Looking Tooth Can Still Be Diseased

One of the frustrating things about EOTRH is that the disease often starts or progresses below the gumline.

An incisor may look only mildly abnormal from the outside, while radiographs show root resorption, widened periodontal spaces, bulbous cementum buildup, or bone changes. This is why “he still has all his front teeth” does not mean “his incisors are healthy.”

The reverse can also be true. Some visible gum changes may be periodontal disease, trauma, or age-related wear rather than advanced EOTRH. That is another reason radiographs are so valuable.

The clinical rule is simple:

If the horse is older and the incisors look abnormal or painful, radiographs are not an optional luxury. They are often the thing that makes the diagnosis clear.

What Else Can Look Like EOTRH?

Not every painful incisor problem is EOTRH. A good veterinary dental exam should also consider other causes.

Possible differentials include:

• Periodontal disease

• Tooth root abscess

• Incisor fracture

• Trauma to the mouth or jaw

• Feed packing between teeth

• Gingivitis

• Oral foreign material

• Malocclusion or abnormal bite forces

• Tooth mobility from age-related support loss

• Oral tumours

• Sinus or facial infection

• Other causes of weight loss, including PPID, parasites, poor forage, chronic pain, liver disease, kidney disease, or systemic illness

UC Davis notes that EOTRH can occur with or separately from periodontal disease and certain oral infections, which can complicate diagnosis. (Center for Equine Health)

This matters because the best treatment depends on what is actually causing the pain. A horse with mild feed packing may not need the same plan as a horse with severe EOTRH and draining tracts.

Can EOTRH Be Treated Without Extraction?

In mild cases, conservative management may help comfort for a time, but it does not cure the disease.

Conservative care may include:

• Removing feed trapped between teeth

• Gentle cleaning of the incisor area

• Managing secondary infection

• Pain relief under veterinary direction

• Dietary modification

• Softer feed

• Regular monitoring

• Repeat dental exams and radiographs

UC Davis notes that mild cases may involve removing feed accumulation, topical medications, antibiotics, pain management, and dietary changes, but also states that there is currently no way to slow disease progression. (Center for Equine Health)

That last point is important.

Conservative care can sometimes buy time. It can reduce infection or make the horse more comfortable temporarily. But if the teeth are painful, unstable, infected, fractured, or severely affected on radiographs, conservative care is unlikely to be enough long term.

When Is Extraction Needed?

Extraction is usually considered when affected teeth are painful, loose, infected, fractured, severely resorbed, or associated with draining tracts and significant radiographic disease.

Merck Veterinary Manual states that incisor extraction is indicated if the patient appears to be suffering from pain induced by EOTRH. (Merck Veterinary Manual)

Extraction may be recommended when there is:

• Persistent incisor pain

• Loose incisors

• Tooth fracture

• Draining tracts

• Abscessation

• Severe gum recession

• Marked hypercementosis

• Advanced resorption on radiographs

• Weight loss linked to mouth pain

• Poor quality of life

• Failure of conservative management

Some horses need only selected teeth removed. Others need multiple incisors or all incisors removed. The decision should be based on radiographs, clinical signs, comfort, infection, and the horse’s overall health.

The hardest part for many owners is accepting that removing teeth can be kinder than leaving them in. But a diseased tooth that looks “present” is not necessarily functional. If it is painful, infected, or unstable, keeping it may prolong suffering.

Can a Horse Eat Without Incisors?

Yes. Many horses do very well without incisors.

The incisors are used mainly for biting and cropping grass. The cheek teeth at the back of the mouth do the grinding. If the cheek teeth are functional, many horses can still chew hay, soaked feed, and forage alternatives well after incisor extraction.

UC Davis notes that many horses improve in quality of life after surgery, and that depending on which teeth are removed, some horses do not require major dietary changes because they chew with their cheek teeth. Many learn to graze using their lips and tongue. (Center for Equine Health)

Virginia Tech also notes that horses typically respond well to complete incisor extractions, with appetite often returning quickly after surgery. (VetMed EMC)

Some horses may need:

• Softer feed during healing

• Soaked hay cubes or pellets

• Chopped forage

• Senior feed

• More careful winter feeding

• Weight monitoring

• Help maintaining intake if grazing is limited

But many owners report a brighter horse after painful incisors are removed. Appetite improves. Mood improves. Weight can return. The horse often seems more comfortable because the chronic pain source is gone.

What Happens After EOTRH Extraction?

After extraction, your vet will give a specific aftercare plan based on how many teeth were removed and how the surgery went.

Aftercare may include:

• Pain relief

• Antibiotics if indicated

• Soft soaked feed

• Avoiding hard treats during healing

• Monitoring for bleeding

• Monitoring for swelling

• Checking for discharge or infection

• Keeping feed areas clean

• Follow-up dental checks

• Repeat radiographs if needed

Some horses may have the tongue protrude slightly after multiple incisor extractions. This can look unusual, but it is often a cosmetic issue rather than a welfare issue if the horse is comfortable, eating, and maintaining weight. UC Davis notes tongue protrusion can occur depending on the number and location of teeth removed. (Center for Equine Health)

The recovery goal is simple:

The horse should become more comfortable, eat more willingly, and maintain or regain condition.

If appetite does not improve, weight continues to fall, or there is swelling, discharge, fever, or persistent pain, the horse needs reassessment.

What Should You Do If You Suspect EOTRH?

If your older horse is showing signs of incisor pain, act in stages.

1. Watch the horse eat

Look closely at how the horse handles different foods.

Check whether they:

• Bite grass normally

• Refuse carrots or apples

• Drop feed

• Chew slowly

• Pull away when biting

• Leave hay behind

• Prefer soaked feed

• Quid forage

• Salivate more than usual

Do not just check whether the feed bin is empty. Watch the mechanics of eating.

2. Look at the incisors and gums

From a safe position, look for:

• Gum redness

• Gum swelling

• Gum recession

• Bleeding

• Loose teeth

• Fractured teeth

• Discoloured teeth

• Bulbous swelling near the roots

• Feed packed between teeth

• Small draining tracts

• Bad smell

Do not force the mouth open or put yourself at risk. A painful horse can react suddenly.

3. Book a veterinary dental exam

Ask specifically for the incisors and canines to be assessed, not just the cheek teeth.

A complete exam may require sedation, a speculum, and dental radiographs.

The AAEP states that horses should have a dental exam at least once yearly, and horses over 10 may need more frequent visits, often every 6 months, especially if dental issues are present.

4. Ask whether radiographs are needed

For suspected EOTRH, radiographs are usually central to diagnosis and treatment planning.

Radiographs are especially important if there is:

• Gum recession

• Tooth mobility

• Fracture

• Draining tracts

• Pain when incisors are touched

• Bad breath

• Weight loss

• Difficulty grazing

• Multiple abnormal incisors

5. Adjust feeding while waiting

If your horse is struggling to bite or chew, make feed easier and safer.

Consider:

• Soaked feed

• Soaked hay cubes

• Soaked hay pellets

• Chopped forage

• Senior feed

• Smaller meals

• Separate feeding away from herd competition

Avoid hard treats if biting is painful.

Common Mistakes Owners Make With EOTRH

Waiting for the horse to stop eating

Many horses with EOTRH continue eating despite pain. Do not wait for complete refusal of food before investigating.

Assuming incisor disease is not serious

Front teeth matter. Painful incisors can affect grazing, feed intake, behaviour, and quality of life.

Floating the mouth but not checking the incisors properly

Routine dental work is important, but EOTRH often needs radiographs and targeted incisor assessment.

Using pain relief instead of getting a diagnosis

Pain relief may temporarily improve comfort, but it does not fix diseased roots, fractures, infection, or advanced EOTRH.

Delaying extraction because the teeth “look too important”

Painful diseased teeth are not useful teeth. Many horses are happier once severely affected incisors are removed.

Assuming weight loss is just old age

Senior horses lose weight for reasons. Dental disease is common, but PPID, poor forage, parasites, chronic pain, and systemic illness also need to be considered.

Can EOTRH Be Prevented?

There is no proven way to prevent EOTRH completely.

UC Davis states that there are currently no definitive approaches to prevention, although ongoing monitoring in older horses and periodic radiographs may be useful. (Center for Equine Health)

That does not mean owners are powerless. The best approach is early detection and regular dental monitoring.

Practical prevention and monitoring steps include:

• Schedule regular dental exams, at least yearly for adult horses

• Consider 6-month checks for older horses or horses with dental disease

• Ask for incisor assessment in senior horses

• Use radiographs when EOTRH is suspected

• Track body weight and body condition

• Watch grazing behaviour

• Monitor changes in bridling or bit acceptance

• Avoid ignoring bad breath, gum recession, or feed packing

• Keep a log of quidding, appetite changes, and weight trends

• Review PPID risk in older horses with your vet

• Feed a diet the horse can physically manage

The aim is not to stop every dental change from happening. The aim is to catch painful disease before the horse loses significant condition or quality of life.

What Is the Outlook for Horses With EOTRH?

The outlook depends on disease severity, how quickly it is recognized, whether the horse has other health conditions, and whether painful teeth are treated appropriately.

For horses with mild disease, careful monitoring and supportive care may maintain comfort for a period.

For horses with advanced painful disease, extraction often gives the best chance of meaningful relief.

UC Davis describes the prognosis after surgery as generally good, with many horses experiencing improved quality of life. (Center for Equine Health)

The most reassuring point for owners is this:

A horse does not need perfect incisors to have a good life. A horse needs a comfortable mouth, enough nutrition, and a feeding plan that matches what the mouth can do.

Frequently Asked Questions

Is EOTRH painful for horses?

Yes. EOTRH can be very painful, especially when teeth are loose, fractured, infected, or severely affected below the gumline. Some horses hide the pain well, so subtle signs like refusing carrots or resisting mouth handling should be taken seriously.

What age do horses get EOTRH?

EOTRH is most common in horses over 15, but it can occur earlier. UC Davis notes that mild cases have been reported in horses as young as 10. (Center for Equine Health)

Do all horses with EOTRH need their incisors removed?

No. Mild cases may be monitored and managed conservatively for a time. However, painful, infected, loose, fractured, or severely affected teeth often need extraction to give lasting relief.

Can EOTRH be diagnosed without x-rays?

A vet may suspect EOTRH from the history and oral exam, but dental radiographs are essential for confirming the diagnosis, staging severity, and planning treatment.

Can a horse graze after incisor extraction?

Many horses can graze after incisor extraction by using their lips and tongue. Some need extra dietary support, especially if pasture is limited or cheek teeth are also diseased.

Is EOTRH contagious?

EOTRH is not considered a simple contagious disease that spreads from horse to horse. The cause is unclear and likely involves multiple factors, including age, dental stress, periodontal disease, microorganisms, health status, and genetics.

What should I feed a horse with painful incisors?

While waiting for veterinary assessment, softer feeds are usually easier. Options may include soaked senior feed, soaked hay cubes, soaked hay pellets, chopped forage, or other safe forage replacements. Avoid hard treats if biting is painful.

Final Thoughts

EOTRH is easy to underestimate because it often starts quietly. A senior horse may still eat, still behave reasonably well, and still appear settled, while gradually avoiding the things that make the incisors hurt.

The signs that matter most are changes in biting, grazing, mouth handling, appetite, weight, gum health, and comfort around the bit. If an older horse refuses carrots, drops feed, develops bad breath, shows gum recession, or starts losing weight, the incisors deserve proper attention.

Radiographs are central because EOTRH is often worse below the gumline than it appears from the outside. Conservative care may help mild cases temporarily, but painful advanced disease often needs extraction. That can feel like a big decision, but many horses become brighter, more comfortable, and better able to maintain condition once painful teeth are removed.

A horse can live well without diseased front teeth. What they cannot do well with is chronic dental pain that goes unrecognized.

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If you are unsure whether your horse’s incisor changes are mild, painful, or urgent, ASK A VET™ can help you think through the signs, prepare for a dental exam, and decide whether radiographs or prompt veterinary care are needed.