How To Tell A Horse’s Age

Some horses have birth certificates or registration papers, making it easy to tell how old they are as it is a simple matter of arithmetic. Other horses have no papers and are sold from home to home. No one keeps track of the horse’s age, people forget details, and suddenly it becomes a matter of guessing how old the horse is.

Some people regard aging a horse as a dark art, shrouded in mystery and only possible for those gifted in some supernatural way. There is quite a bit of science behind determining a horse’s age, and it is a skill that can be learned. However, it will never be a precise science as there are always individual variations based on genetic differences and conditions in which the horse has been kept.

Horses are primarily aged by examining their teeth. The teeth grow in, and certain markers on the teeth occur at specific ages. The general body shape and sometimes graying can also indicate age, although this is less reliable. There is individual variation based on genetics and the environment.    

As horses are primarily aged by examining their teeth, it is essential to have an understanding of horse dentition. This article will give you details on when teeth erupt in foals, the changes between temporary and permanent dentition, and changes that teeth undergo. In addition, body shape and changes in marking will be discussed as they can also give clues to a horse’s age.

Veterinary Records

Firstly, why do we want to know the age of our horses? The age of the horse can give you an indication of the amount of schooling and handling the horse has had that you might potentially buy. Another reason is there are physical bone changes that occur in aging horses – for example, arthritis, sidebone, and ringbone. A horse that is 17 years old is much more likely to have these bony changes than a horse under 10 years old. This information can tell you, as the potential owner or owner, to know the capabilities and competitive life of the horse.

The most accurate and obvious way to tell a horse’s age is by looking at their history and veterinarian records, such as their registration papers or passports. The breeder or previous owner can also provide you with the age or estimated age of the horse. In the case of rescue or adopted horses, other methods to know the horse’s age is needed.

Thoroughbred horses and other purebred horses may have upper lip tattoos for identification purposes. The information of this horse and the number on the inside of their upper lip will be registered on the racehorse database, where you can search for their date of birth and breeding.

Other registered purebreds will often have branding – freeze or hot branding –  on their hind quarter or just above their elbow. This brand can give you the stud or owner information. You can then find the owner or stud and, through them, find out the age of the horse.

Lastly, if you have no background on a horse, you can scan their neck for a microchip. A vet will have a microchip scanner and can then give you the microchip number. The microchips registration number can be searched on the database, and you can find all the information you will need on the horse.

Dental Patterns

The teeth of a horse are designed to cut grass and grind the grass down to small pieces that can be easily swallowed. Horse’s teeth never stop growing, this continual growth means that the horse relies on naturally wearing down the teeth by the grinding action when they chew grass, or an equine dentist is used to float the horse’s teeth and ensure that the griding surface is even.

Stabled horses appear younger than they are as these horses usually receive dental care and chew concentrates and cut grass. Wild or range horses that live out may appear older by their dental anatomy due to the more natural wear on their teeth.

The horse has multiple pairs of teeth. A horse has 12 incisors in the front of the mouth and used to cut the grass. Behind the incisors, the canines can be found in stallions and geldings. The canines are used by wild horses for fighting and defending themselves. At the back of the mouth, the horse has 24 molars used to grind down their feed and grass before they swallow.

Step 1: The color of the teeth

            In a young horse – from birth to 2.5 years old – they still have their milk teeth, which are white. After around 2.5 years, their permanent teeth start to erupt, and these teeth are a more cream to yellow color. As the horse ages more and becomes senior – 20 years – their teeth go brown.

Step 2: Look at the chewing surface

            The incisors of a horse and its overall shape can give you an indication of its age as well. Milk teeth are oval and flat, adult incisors are more circular, and senior horses have triangle incisors. The temporary or milk incisors erupt at certain stages after birth as well. These incisors erupt at 8 days, 8 weeks, and 8 months old.

The 4 incisors in the middle of the mouth erupt at around 3 years old. The next two pairs on each side of those middle incisors erupt at 4 years old, and the last two pairs erupt at 5 years old.

Step 3 – Look for the wearing of the cups, stars ad Galvayne’s groove

As a horse ages, the teeth still grow continually, and they are also continually worn down. The shape and appearance of the chewing surface of the teeth also change. As seen in the picture I have attached, you can see how the angle and the appearance of the surfaces will change.

A dental cup or infundibulum is a deep indenture in the center of the tooth. Cups are used to determine age in horses as the size, presence, and shape of the cup will give you an estimated age for the horse. The cups disappear at different ages of the horses’ lives. Both the upper and lower canines need to be examined for cups to accurately age a horse. The lower canines smooth out – the cups disappear – before the upper canines. Here is the process:

Stars are dark brown round spots that are present toward the front of the tooth as the tooth wears down over time. Dental stars are present from around 8 to 10 years old.

The Galvayne’s groove can be used to guestimate older horse’s age. Galvayne’s groove is a groove that appears on the corner incisors that start at the gums’ margin around 10 years old. As the tooth grows, the groove lengthens down the tooth.

When the groove is halfway down the tooth, the horse is around 15 years old. When the groove has reached the bottom of the tooth, the horse is around 20 years old. From there, the groove will recede and disappear over time. At 25 years old, the groove is halfway down the tooth and almost gone. By 30 years old, the groove will be gone completely.

Step 4 – Look at the angle at which the teeth meet

A colt or filly’s teeth will meet at a vertical line. From 5 years old, the teeth will start to slant, and the angle at which the teeth meet will decrease over time. From 20 years and older, the angle will become very acute. The incisors will start to slant forward and outward.

Due to the slanting, the corner incisors (the outermost incisors) do not touch and wear evenly. This causes hooks or sharp points to form. These hooks can be found on a horse from 7 years and older. Thus regular dental care is needed to minimize this from happening. The hook or notch can disappear and will likely reappear at the ages 12 to 15 old.

Is Aging A Horse By Teeth Accurate?

There is a lot of individual difference in tooth changes in horses. This is governed by genetics and environmental conditions as well as the care the horse has received. For example, a horse left to forage in cold winter months may eat bark or other rough fibrous material to survive. This will result in teeth that are much more worn down than a horse that is fed good quality hay which is not harsh on the teeth.

Certain breeds such as draughts are known to wear down their teeth more quickly than other breeds such as Arab horses. This factor is probably related to the massive weight and power in the draught breed jaw. There are also breed differences in the hardness of the teeth.

Some people are better at aging horses by their teeth than others, which often comes down to experience and exposure. Therefore, it would be useful for you to begin examining the teeth of horses of known age so that you can get exposure to the changes that occur in a horse’s mouth.

Foal Teeth

Foals are usually born without teeth, although a few may be born with their central incisors. The incisors are the middle teeth in the mouth. Foals grow their first four incisors within the first eight days of life. There will be two incisors on the bottom and two on the top. The intermediate or middle (or lateral) incisors are usually seen between six to eight weeks. At six to eight months, the final incisors known as the corner incisors will be present.

Premolars develop at about two weeks of age. There will be twelve premolars—three on each side of the mandibular (lower jaw) and maxilla (top jaw). By eight months, the foal will twenty-four teeth in total. They will be:

1. Six lower incisors
2. Six upper incisors
3. Six lower premolars
4. Six upper premolars.

Based on the eruption of the teeth, you can now get some idea of the age of a foal. These are deciduous, or milk teeth and are wider than they are tall. They have shallow roots and will ultimately be replaced by permanent teeth. 

All the teeth are concave and have small cup-shaped depressions that are also called infundibula. The depressions wear away as the foal chews grass. By one year of age, the first incisors have become smooth, and their cups have disappeared.

The middle and corner incisors will still have their cups. The first premolars will be replaced by permanent teeth at six to nine months. The first permanent molars will make their appearance between nine to fifteen months. 

Foal Body Shape

Foals can be distinguished from small adult horses or ponies based on their body shape. Foals have long legs and small bodies. These proportions differentiate them from their adult counterparts. In addition, foals generally have fluffy, thick coats. These coats usually persist until the foal is about three to six months depending on the season and horse breed.  

Two-Year-Old Horses

The permanent central or middle incisors replace the temporary teeth at approximately two to two and a half years. The corner incisors will show some wear. The horse between two and three years will have mixed permanent and temporary dentition.

Temporary or milk teeth are smaller, have a clearly defined neck, and are usually lighter in color than permanent teeth. The second and third premolars will be replaced by permanent teeth at around two years and eight months to two years and ten months. The second permanent molar will develop between two and a half years to three years.  

Two-year-old horses have lost the long-legged foal look, and their legs look more proportionate to their body size. In fast-growing breeds such as Thoroughbreds, Arabs, and ponies, the two-year-old horse will be almost at its full size. Slow-growing breeds such as draught horses will still have a lot more height to attain.

Two-year-old horses may be at nearly full height, but they will still be slender and have limited muscle development. They will often exhibit juvenile behavior. Two-year-old horses still play a lot with herd members and may lack confidence in new situations.   

Horses do not always grow in the fore and back legs at the same time. You may see a young horse that is described as “bum-high.” This term refers to the fact that the horse’s hind legs have grown longer, and the forelegs did not keep pace. This is normal, and the front legs will grow and level the horse out again.

Some horses may grow quicker in the forelegs, but it is more unusual and gives a rather odd appearance to the horse. Whenever you see an unlevel horse from back to front, you can confidently be sure that it is a young horse.

Three To Four-Year-Old Horses

Horses grow their permanent lateral or middle incisors at three and a half to four years. Their third molar and fourth premolar deciduous teeth are pushed out by their permanent replacements between three and a half to four years of age. Hot-blooded horses that grow fast are beginning to look much more like adults.

Many of them may be ready to start light work and be backed at three and a half to four years. Cold-blooded breeds such a Clydesdales, Shires, Percherons, other draughts, and slow-growing breeds will still look like youngsters compared to adults of their breed.

Five-Year-Old Horses

The five-year-old horse should have all their permanent dentition or attain it during the first six months after they have turned five years old. The permanent teeth are larger and darker, or more yellow, than the milk or temporary teeth.

The permanent incisors are rectangular, being longer than they are wide. The upper and lower incisors in a five-year-old horse touch each other with a roughly 180° angle between them. This angle will change as the horse grows older.

Stallions, geldings, and some mares grow canine teeth. However, not all horses grow canine teeth, and sometimes they occur on only one side. Canines are a small column-shaped tooth that grows between the incisors and the premolars. It is generally seen at around six years of age, although in some horses, it may be seen as early as four years and in others as late as eight years.

This tooth is sometimes called a ‘wolf tooth” in certain countries (Australia and South Africa). This can be confusing as other countries refer to wolf teeth as the first premolar, which erupts at five to six months of age (Britain and the United States of America).

This tooth is often removed as it can interfere with the placement and seating of the bit in the horse’s mouth. It is possible that the tooth remains in the gum and does not erupt but causes pain when the bit touches that area of the gum.  

The five-year-old horse generally looks like an adult horse of its breed. It has developed a muscular top line, and in stallions, a crest will begin to show. At five years of age, horses start to act like mature horses, and they are ready for serious work. The exception is draught horses that continue to grow and often still look like babies at five years old.

Six-Year-Old Horses

The corner incisors begin to show some slight wear when viewed from the side. The infundibula or cups of the central lower incisors are worn away. The lower intermediate or lateral incisors show limited evidence of cups. The mandibular corner incisors still clearly show the infundibula or cups. The angle of occlusion ( where the upper jaw meets the lower jaw) is still approximately 180°.  

Seven To Nine Year Old Horses

The cups on the mandibular intermediate incisors disappear at seven years, and the cups on the lower corner incisors disappear at eight years. At seven years, there is often a hook that develops on the corner incisor. This hook develops because the rear side of the mandibular and maxillary corner incisors do not meet.

This occurs because the teeth are growing longer, and the angle of occlusion is changing. The hook usually disappears at around nine years of age. Horses younger than nine years have rectangular grinding surfaces on the incisors. Draught breed horses will look like adult horses at seven years of age and have completed their growth.

Ten-Year-Old And Older Horses

The grinding surface of the incisors becomes rounded in shape. The corner incisor will begin to show evidence of Galvayne’s Groove. It is initially seen at the gum line in the center of the tooth’s outer surface and moves down the tooth as the horse ages.

By twenty years of age, the groove extends the entire length of the incisor. After twenty, Galvayne’s groove begins to disappear from the top of the tooth nearest the gum line. By thirty years of age, Galvayne’s groove is no longer in evidence.

The cups in the intermediate incisor can no longer be seen at ten and eleven years. By twelve years, the cups in the corner incisors have also been ground away, and the horse is sometimes referred to as a “smooth-mouthed horse.” Another hook will develop on the corner incisor at eleven years of age.

At around ten years of age, the incisors begin to show brown or yellow marks in the center, which are secondary dentine deposits in the pulp cavity. (In some horses, this can be seen as early as eight years). These marks change shape and eventually become oval at around thirteen years and may be known as dental stars.

At fifteen years, the dental stars become more rounded.

Finally, at fifteen to eighteen years, the surface of occlusion on the incisors becomes more triangular-shaped. 

As horses age, the incisors grow longer. The grinding surface where the upper and lower jaws meet changes in its angle, becoming less than 180°. The older the horse, the longer the teeth will be and the smaller the angle. The exact angles and length of the teeth cannot be given due to individual differences.

Physical Changes in Aging Horses

Besides using their teeth and looking at a horse’s veterinary records, horses also age physically and show signs of maturing and aging. Here are some ways you can guess a horse’s age based on its appearance:

• Their mature height and weight
  • Depending on its breed, a horse will show 90% of its final height and 75% of its final weight at around 18 months old. Some breeds, like warmbloods, only mature at the age of 5 – 7 years old. Familiarising yourself with signs of maturity in young horses can help you know which horses are still young versus mature (5 years old older)
• From the age of 18, horses will show signs of aging through grey hairs, losing muscle tone, and have sunken areas right above their eyes. However, the hollows above their eyes can be sunken due to neglect and improper diet.
• Younger horses look out of proportion and have long legs, and maybe croup high. This can give you an indication that the horse is still young and will still grow.
• Horses in their prime 8 to 12 years old will look healthy, happy, mature, and have overall good muscle tone and fat.

Body And Coat Changes In Elderly Horses

It is difficult to accurately tell the age of horses after eleven or twelve years. There are, however, certain body changes that can be seen in geriatric horses. As with humans, some horses can look very good into their old age (twenty to thirty years), and some start to show signs of aging in their late teen years. The body of an old horse usually loses muscle definition, and the muscles may atrophy along the topline (muscles around the spine). In very old horses, the back can become swayed.

The horse may move stiffly if there is arthritis present in joints. This will be worse on cold winter mornings. Horses with arthritis will have difficulty lifting their feet for cleaning and farrier work.  Greying or white hairs may be seen in the face and body of horses that had previously solid color coats. Geriatric horses may lose weight because they cannot chew grass properly. Their digestive tracts become compromised, and they are not able to absorb nutrients effectively.

When is a Horse Considered Old?

Horses can live up to the age of 40 when looked after well and when stabled. Some horses, like us humans, tend to show signs of old age a little bit more than others. Competitive horses that are kept in shape and are exercised daily show fewer signs of aging physically and may not look their age. There are many top competition horses that are still going at the age of 18 and older.

A lot of horse buyers do tend to look at the age of the horse as a deciding factor. Some buyers do not buy horses older than 8 years old as these horses are more likely to have physiological changes such as arthritis, especially if they have competed from a young age. This is why horse riders also tend to start competing horses as early as possible, to get the greatest number of years from that horse in the competition ring.

The wear and tear on a competitive horse must be kept in mind when competing, selling, or buying horses. Some horses do not have a lot of wear and tear, which could be due to good genetics, proper management, and good conformation. However, other horses can show signs of wear and tear from a younger age due to incorrect or undesirable conformation, improper care, and management, hard riding, concussion on the joints, or simply genetics.

Horses used in riding schools or as happy hackers seem to go on for a long time. Usually, because riding schools take very good care of their horses as they are their income, happy hackers do not have a lot of wear and tear because they mostly do outrides and trail rides. These horses are still ridden well into their 20s and even 30s. A horse in its golden years has a lot of knowledge and skills to teach beginner riders the ropes. They make great schoolmasters, which are very valuable to the equine industry.

In my experience, a horse is never “too old.” I have had horses that were going strong at the age of 25 to 35; they taught many young riders how to ride. Some horses are just always young at heart. Horses enjoy working and being loved, and they will show that to you with the proper care and management. Joint supplements and good feeding are imperative to keep an old horse comfortable and in shape.

Here is a handy video to help you age a horse

How Old is My Horse in Human Years?

Have you ever wondered how old your horse is in human years? As many of us know, dogs age considerably quicker, and one year in dog years is the equivalent to 7 human years. But, what about a horse? The calculation of this is not as simple, though—young horse ages faster in human years than an older horse.

Here is a table to make it easier:

Conclusion

It is possible to tell the age of horses from their teeth, body shape, coat color, and behavior. It takes a lot of exposure to horses to become skilled at determining a horse’s age. Even then, some horses’ appearances can be deceptive. There are individual variations based on genetics, environment, and the care the horse receives. If you wish to become skilled in this area, it is good to get as much exposure and experience as possible.

Look at all the horses you meet critically. If they have a known birth date, compare your findings to see if you are accurate in the age-related features you notice. We hope that you now have some idea on how to go about choosing the right horse or aging your current horse.

Sources

https://extension.missouri.edu/publications/g2842

https://www.wikihow.com/Tell-a-Horse%27s-Age-by-Its-Teeth

https://www.equinespot.com/horse-teeth.html

https://horseyhooves.com/horse-years-human-years-chart/

http://www.ckequinehospital.com/page/175/Equine-Dentistry

https://www.uaex.edu/publications/pdf/FSA3123_2020.pdf

https://evds.net.au/tips-and-info/wolf-teeth

http://www.vivo.colostate.edu/hbooks/pathphys/digestion/pregastric/aginghorses.html