Do you know my age??
Horses' teeth are often used to estimate the animal's age,
hence the sayings "long in the tooth" and "Don't look a gift
horse in the mouth".
The Importance of Determining
the Age of Horses
Uses:
 Validate advertised age when buying
 Confirming age when racing or showing
 Feeding for proper nutrition at various life
stages
Aging by Teeth
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Not foolproof
An art that requires skill and
experience
Very old method of aging horses
Error increases with horse’s age
Becomes an educated guess after
horse is older than 14 years
Stabled horses tend to appear
younger (less tooth wear)
Pastured horses tend to appear
older (more tooth wear)
Bishoping- altering teeth to hide age
Equine Tooth Structure
Maxilla
Wolf Tooth
(when present)
Canines
Incisors
Mandible
Molars
Premolars
Horses have 24 temporary teeth and up to 42 permanent teeth
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Deciduous
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Permanents
Dentition
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Hypsodonts
Two times
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Incisors 3/3
Canines 1/1
Premolars 3 or 4/3
Molars 3/3
Male total of 40 or 42; female total 36 to 40
Young horse has 24 deciduous teeth
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Milk teeth
12 incisors
12 molars
Estimating age using tooth eruption
There are 24 deciduous teeth (“caps”).
These come out in pairs, and are pushed
out later by the permanent teeth.
 The “caps” are usually present at birth or
by 1 to 2 weeks of age.
 Rule of 3 eights: I1- 8 days, I2- 8 weeks,
and I3- 8 months
-charts may show these as Di1, Di2, Di3
 The number of permanent teeth may vary,
depending on if the horse has wolf teeth or
canines.
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Permanent Incisors will erupt
I1- at 2 ½ years
I2- at 3 ½ years
I3- at 4 ½ years
Horses will have a “full” mouth at 5 years of
age
Estimating age using tooth
eruption cont…..
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Between zero to four wolf teeth, which are
vestigial premolars and not canines as the
name may suggest. About 13-32% of all
horses also are born with wolf teeth, with
most of those having only one or two.
They are equally common in male and
female horses and much more likely to be
on the upper jaw
Most mares have 36, and most male
horses have 42.
Cups, stars and spots:
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The cup is the center of the
infundibulum. Wear of the occlusal
surface causes the cup to get
smaller and eventually disappear
from all lower incisors at about 6-8
years of age leaving the enamel
spot in its place. The enamel spot
is the deepest part of the
infundibulum. The dental star
corresponds with the pulp cavity
and appears at 8 years of age in
the first incisor. It appears as a line
and then changes to a large, round
spot as the occlusal surface is
worn further.
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The anatomic relationships between incisor anatomy and the
cups and stars seen on the occlusal surface as they wear are
depicted in the images and diagrams immediately above. The
image on the right is shows an incisor of a young horse cut
longitudinally while still in the jaw.
Equine Tooth Structure
Central Incisors
(also pincers or nippers)
Intermediate
Incisors
Corner Incisors
Age is determined using the 12 front teeth (incisors)
Mouthing a Horse for Age
In Real Life: Hold the tongue out and to the side with your hand. This
restraint provides an unobstructed view and is not painful to the
horse.
Tooth Emergence
Temporary Teeth (Baby Teeth)
Temporary pincers: Birth - 10 days
Temporary intermediates: 4 – 6 weeks
Temporary corners: 6– 10 months
Tooth Emergence
Permanent Teeth
6 years old
Canine teeth
appear: 4-5
years
Permanent
corners: 4
½ years
Permanent pincers:
2 ½ years
Permanent
intermediates:
3 ½ years
Tooth Wear
As horses age, “caps” disappear from incisors
6 years old
15 years old
As horses age, teeth become more triangular-shaped
Wolf tooth
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A typically small
maxillary wolf tooth
(premolar [PM] 1) is
present just rostral
to PM2.
Galvayne’s Groove
A mark on the upper corner incisors that appears and
disappears in a predictable pattern as horses age
Usually appears around the
age of 10 years.
Galvayne’s Groove
A mark on the upper corner incisors that appears and
disappears in a predictable pattern as horses age
Groove is usually half way
down at age 15
Galvayne’s Groove
A mark on the upper corner incisors that appears and
disappears in a predictable pattern as horses age
By age 20 the groove usually
extends the full length of the
tooth
Galvayne’s Groove
A mark on the upper corner incisors that appears and
disappears in a predictable pattern as horses age
Groove begins to recede
around age 21
Galvayne’s Groove
A mark on the upper corner incisors that appears and
disappears in a predictable pattern as horses age
Groove is halfway gone by age
25 and disappears completely
around age 30.
7 year notch
 Disappears at 8 years,
returns at 11
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Length with age
“long in the tooth”
I1
I2
I3
Baby erupt
8 days
8 weeks
8 months
Permanents erupt
2 1/2
3 1/2
4½
Cups gone
6 years
7 years
8 years
Dental Star
8years
9 years
10 years
Galvayne’s
groove
10-30 years
Seven year notch
7years, and 11
years
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Shape of teeth
Round 9-11 years
Triangular 14-17 years
Biangular 18-21 years
Aging Using Teeth
Determine the most likely age for the following horse
1. 7 years
2. 14 years
3. 21 years
4. 28 years
Wear – No
Cups
Aging Using Teeth
Determine the most likely age for the following horse
1. 1 year
2. 8 years
3. 17 years
Oval Shaped
Teeth
No Canines
4. 26 years
Aging Using Teeth
Which horse is older?
A
B
Common ages for tooth eruption
(page 248 LACP)
Type of tooth
Number
Deciduous
Permanent
Incisor
First (central)
birth to 8 days
2.5 yrs
Incisor
Second (intermediate)
4.5-6 weeks
3.5-4 yrs
Incisor
Third (corner)
6-9 months
4.5-5 yrs
Absent
3.5-5 yrs, some around
6 yrs (if ever)
Canine
Premolar
First (wolf)
Absent
6 months to 3 years (if ever)
Premolar
Second
birth to 2 weeks
2-3 yrs
Premolar
Third
birth to 2 weeks
2.5-3 yrs
Premolar
Fourth
birth to 2 weeks
3-4 yrs
Molar
First
Absent
9-12 months
Molar
Second
Absent
2 yrs
Molar
Third
Absent
3-4 yrs
Dental Care
Routine dental exams
-young foals, yearlings, 18months to 2 years
(first bitted), and every 6 months to annually
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Floating teeth- rasping sharp edges off the
cheek teeth (premolars and molars)
Abnormalities
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Overshot/Undershot jaw
Lack/Excessive incisor wear
Offset bite
Curvatures or slantsHooksWave mouth- teeth in arcade become different heights
Missing teeth- allows opposite tooth to overgrow
Sheared Molars- enamel overgrowth
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Signs of a problem:
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Abnormal bitting or head carriage
Headshaking
Quidding or dropping food
Excessive salivation
Weight loss, general poor health
Swelling or discharge in mandible maxilla or nasal discharge
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A.A.E.P 1996. The official Guide for Determining the Age of the Horse.
American Association of Equine Practitioners. Golden, Colorado.
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Blackwell. 2009. Equine Manual for Veterinary Technicians. Blackwell
Publishing. Ames, Iowa
Equine Dental Care
Why is it important for my horse to have
regular dental examinations?
An oral examination should be an essential
part of an annual physical examination by a
veterinarian.
Regular examinations also help identify dental
problems while they are still in the early stage,
which decreases the chances that the dental
problem can lead to other serious health
issues for the horse.
How often should a horse receive a dental exam?
At the minimum, all horses should receive a
yearly dental exam.
Horses aged 2 to 5 years may require more
frequent dental exams than older horses, as there
is an extraordinary amount of dental maturation
during this period.
Senior horses (20 years old or older) are at
increased risk for developing periodontal disease
and face the additional challenges of advancing
age.
Twice-a-year examinations are often required to
keep their teeth functioning properly into their
third and fourth decades of life.
How will I know if my horse has a dental
problem?
Horses with dental problems may show obvious
signs such as pain or irritation, or they may
show no noticeable signs at all.
By the time the average owner notices a
problem, such as loss of feed from the mouth
while eating, fighting the bit or foul odor from the
mouth or nostrils, the abnormalities inside the
mouth are likely to be severe.
How many teeth does a horse have?
A typical adult male horse has 42 permanent teeth,
while a typical mare may have 36 teeth, because
mares are less likely to have canine (bridle) teeth.
A horse’s permanent teeth are about four inches long.
Do horses have “baby” teeth?
Like humans, horses have two sets of teeth in
their lifetimes.
The baby teeth, called deciduous teeth, are
temporary.
The first deciduous incisors may erupt before
the foal is born.
The last deciduous teeth come in when the
horse is about eight months of age.
These “baby” teeth will begin to be replaced by
adult teeth around the age of 2 ½, and by age
5-6, most horses have all of their permanent
teeth.
What does it mean to “float” a horse’s teeth?
Routine maintenance of a horse’s
mouth has been historically referred
to as “floating.”
Floating removes the sharp enamel
points.
Occlusal equilibration is the term now
used to describe smoothing enamel
points, correcting malocclusion (faulty
meeting of the upper and lower teeth),
balancing the dental arcades and
correcting other dental problems.
What is the difference between traditional
floating and power floating?
Traditionally, horses have had their sharp
enamel points and dental crown
elongations reduced with hand-held rasps
(floats).
These manual dental instruments have
improved in quality over the past 20 years
but still require a reasonable amount of
manual dexterity, physical strength and
"elbow grease.”
High quality dental tools powered by
electricity or compressed air have become
readily available and affordable over the
past 10 years. These instruments reduce
the physical effort that is required, and with
expertise and caution, allow for more
complete and efficient dental care.
Will my horse need to be sedated during
a dental exam?
Some horses find the process of
having their mouth opened and
instruments placed in the oral
cavity to be stressful.
For a complete oral examination
and good quality corrective care,
most horses benefit from a mild
sedative to relieve any stress or
unnecessary movement on the
patient's part.
When the horse is sedated, it
allows us to do a better job in a
safer way
What are wolf teeth?
Wolf teeth are the remnants of the first
premolars that have now become obsolete
with the evolution of the horse.
The most common first premolars seen in the
horse are the uppers and they are shaped
similar to small canine teeth.
This is why they are often described as wolf
teeth. These sharp teeth, if present, are in the
area of the mouth where the bit fits.
Wolf teeth may cause the horse some
discomfort when pressure is placed on the
bit. Therefore, these teeth are usually
removed in young riding horses.
What is cribbing and how does it affect
dental care?
Cribbing is a stereotypic behavior, or vice, that
some horses develop.
The horse exhibits cribbing by grabbing onto an
inanimate object (fence posts, buckets, stall walls,
etc.) with its incisor teeth, pulling the object and
often making a sucking sound.
Because these horses spend the majority of their
time during the day preoccupied with this behavior
rather than grazing or eating, they quite often have
dental wear problems.
The upper incisor teeth (front teeth) are often worn
excessively from hours of abnormal attrition. These
horses are referred to as "stump suckers.”
How do diet, pasture management and
stabling impact dental wear?
Mother Nature designed horses to be pasture grazing animals.
Horses in the wild normally spend 16 hours a day with their
heads down, grazing grass.
For a horse to properly process 20-30 pounds of wet-grass
forage a day, it uses a wide, crushing chewing pattern.
This allows the incisor teeth and cheek teeth to wear at a
normal and even rate.
Under artificial conditions, horses are fed an abnormal diet
(grain and hay) for shorter intervals during the day, with an
abnormal head posture (feed tub or hay rack).
All of these conditions alter the chewing pattern and adversely
affect the way teeth are worn over time.
Do donkeys and mules require different
dental care than do horses?
All equine species have the
same type dentition.
We see the same types of
pathology and wear patterns in
donkeys, mules, zebras and
horses.
Under current domestication
practices, all require regular
dental care.
Clean and Sanitary
All dental instruments, the
speculum (device that
holds the horse’s mouth
open), buckets, etc are all
cleaned and washed with
an antimicrobial
disinfectant (Nolvasan)
between each and every
horse. No exceptions!
Equipped to do the job
Equine dentist should be
well equipped with good
instrumentation, both
motorized and nonmotorized.
Examination noting pathology and
record keeping
A complete examination with the
use of surgical grade lighting, a
dental mirror, and other
appropriate instruments should
be done.
A record indicating all teeth in
your horse’s mouth, noting
location and significance of all
abnormalities, what work needs
to be done, and time of follow
up examinations should also be
included.
Diagnostic Imaging
Dentist should have
access to diagnostic
imaging equipment such
as x-rays, preferably
digital x-rays.
This allows us to uncover
and manage a host of
equine dental
abnormalities.
Sources
James M. Casey, D.V.M., M.S.
www.equinehorsevet.com