Determining how to age a horse by their teeth is an old art. People have been visualizing the eruption and wearing of teeth to determine the age of a horse for a long time. It is due to the characteristic of equine teeth which follow a certain pattern from eruption to their wear and tear throughout the life of the horse.

Until recently when horse authorities started keeping the record of the horse aging, veteran horsemen took pride in their abilities to determine the age of the horse by his teeth. However, determining the age of horses by their teeth is not accurate science. As the horse gets older, it becomes difficult to guess the accurate age of horse.

 Let’s have a look inside the horse’s mouth. 

Teeth of horse

A mature horse has usually 36 teeth in his mouth. Like in humans, initially deciduous teeth (Baby teeth) erupt which are then gradually replaced by permanent teeth. Deciduous teeth are more cylindrical and whiter in color as compared to permanent teeth, more yellow in color and square in shape.

Different types of teeth in a horse’s mouth are named as:

Incisors: Front 06 pairs of teeth in the upper and lower jaw are called pincers, or incisors. These teeth are used for age determination. Two pairs in the center are called central incisors, teeth besides the central are called intermediate and the last pair on each side is comprised of corner incisors.

Canines: Male horses usually have 04 canine teeth behind their corner incisors. In mares, canines are usually underdeveloped or may not be present.

Wolf Teeth: First premolars are rudimentary and called wolf teeth. They are usually removed due to their interference with the bit of performance horses.

Molars: Horses have 08 pairs of premolars and 06 pairs of molar teeth. They don’t help in age determination because they can’t be easily viewed.

Aging a horse by it’s teeth: Determining Age of Horse by Teeth Examination

The age of a horse is determined by a variety of changes that occur in the shape, surface, and angle of teeth as the horse ages.

Things that are considered for guessing the age of a horse are a sequence of deciduous and permanent teeth eruption, appearance and disappearance of different structures on the chewing surface of teeth, their angle of incidence and the list goes on. Here I will mention some distinct demarcation of horse’s teeth concerning age determination.

Birth to 05 years of age

A foal is born with two pairs of incisors or they erupt within two weeks after birth. A thumb rule for the eruption of deciduous central, intermediate and corner incisors is 08days, 08weeks, and 08months respectively. All pairs of deciduous premolars also erupt during the first month of foal life.  

At the age of one year, central and intermediate incisors start wearing and the surface of the corners start touching each other.

A two-year mouth has all deciduous teeth and can be confused with an older horse. So, distinguishing deciduous teeth from permanent teeth is very important. Corner incisors will be in full wear with the flat surfaces of the centrals and intermediates.

In three-year-old mouth central pairs of temporary incisors are replaced by permanent teeth. Deciduous intermediates have deep cups and the lower corners are showing little enamel.

A four-year horse usually has permanent central and intermediate teeth with deciduous corners. Permanent incisors are in wear and deciduous incisors are ready to shed. Canines have also appeared. Aging a horse by it’s teeth is a very useful way to accurately identify the age of any horse.

At five years, all the deciduous teeth are replaced by permanent teeth, and the horse is called full mouth. Cups appeared on both upper and lower central and intermediate. Corners show very little wear.

06 years to 10 years of age

As the incisor teeth wear, there appear different structures on the table of teeth. After the eruption of permanent incisors, the enamel of the crown wears to produce cups from central to corner incisors gradually. From 06 to 10 years of age, the disappearance of cups occurs.  

Up until the 08th year, cups disappeared from intermediate and central incisors while cups of corner take more years to be disappeared completely.

After 08 years, there starts the wearing of infundibulum which gives rise to stars in lower incisors. Star appears as a sharp line in the central incisors first and then in intermediates and corners. A 09 and 10-year mouth has more oval teeth with increased steepness in the angle of incidence.

11 years to 15 years of age

An 11-year mouth still has remnants of cups in the central and intermediate incisors. The cups may appear clearer in the upper incisors. Stars become more centralized in the incisors with the appearance of a white spots in between the stars.

A 12 years old horse has no difference except the length and angularity of the teeth increases. It can be differentiated by the presence of a cup in the upper corners. After the disappearance of cups in all teeth, a horse is called a smooth mouth. And it becomes very difficult to determine the age after this.

In the 15th year, all the cups have gone disappeared and lower incisors appear smaller than the upper incisors and stars taking a centralized position on the teeth table.

16 years and over

The teeth of a horse older than 15 years of age have no colors on the teeth table except dental star. The angle of incidence increases and teeth become triangular to biangular from front to back. In older horses, the age estimation becomes difficult as compared to horses less than 10 years of age.  

Galvayne’s Groove

It is a dark brownish groove that appears on the surface of corner incisors. Galvayne’s groove starts appearing at the age of 11 and extends downward to the ½ of the corner incisor until the age of 15. Groove covers the entire length of the incisor till the age of 20 and then starts disappearing from the upper end.

At the age of 25 Galvayne’s groove disappears up to the half of the upper corner incisor and disappears completely in a 30 years old horse.

Aging a horse by it’s teeth: Bottom line

Wearing of teeth provides an easy way to determine the age of a horse, however, it is not a foolproof method. Several factors like genetics, feed, and management influence the wearing pattern of the teeth. The stabled horse appears younger as compared to grazing horses, because grass-feeding cause rapid wearing. Although, in the absence of an aging record, this method can provide several clues to determine the approximate age of the horse.

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