Deciduous
Teeth in Horses
by Larry Kimberlin, D.V.M.
A very big issue for every horse under five years of age is the eruption
of the baby or deciduous teeth and the formation of a full set of
permanent teeth. This is also one of the ways that the age of a young
horse can be determined.
The
first five years are very busy years in the horse’s mouth. There
can be up to forty four teeth that erupt and grow into occlusion.
This includes twelve incisors, four canine teeth, fourteen premolars
and twelve molars. There are so many teeth coming and going, it is
hard to tell what is what without a scorecard!
The
foal is usually born without incisors (the front teeth that are seen
when you lift up the lip). Horses have twelve incisors – three
upper pair and three lower pair. The first incisors usually break
through the skin in about one week. These are the central incisors.
The next pair – the middle incisors – erupt at about eight
weeks and the last pair – called the lateral incisors –
come in at about eight months. By one year of age all the incisors
are in. The deciduous incisors are much smaller than the permanent
incisors that will take their place.
The
permanent incisors are a good way to age a young horse. The permanent
incisors come in at 2 1/2 years, 3 ½ years and 4 ½ years
respectively. This photo illustrates a 4 year old horse with permanent
central and middle incisors and deciduous lateral incisors (arrows
point to deciduous teeth).
The
young horse is born with twelve deciduous premolar cheek teeth. These
teeth are also replaced by the permanent premolars in a similar fashion
to the incisors. These teeth come in at about 2 years, 2 ½
years and 3 years. These times are approximate and can vary by 2-4
months ( depending on the breed) -but are pretty consistent . This
picture illustrates the permanent premolars coming in below the deciduous.
When
permanent teeth come in they push the deciduous tooth out of the way
– disrupting its blood supply and causing it to loosen and “shed”.
The baby teeth sometimes do not shed as they should and remain attached
to the permanent tooth. These are called caps and cause pain and chewing
problems due to the uneven surface similar to having a popcorn kernel
caught in your teeth.
The
timely shedding and eruption of the permanent teeth is very important
to the long term health of the mouth. If deciduous teeth do not shed
at the proper time the permanent teeth that are to replace them will
become impacted and come in crooked. This will cause bite problems
and discomfort for the horse.
By
knowing when the permanent and baby teeth come in you can tell the
age of a young horse within a few months. Whenever an owner complains
of chewing problems or bitting problems in a horse under five years
of age the first thing we look for are retained caps. The picture
below shows a skull with a view of caps and the permanent teeth coming
in underneath.
It
is very important to have your horse’s teeth checked yearly
during these formative years. If there are problems with retained
deciduous teeth or impaction you may need to have them checked two
to three times a year.
Just
as in human dentistry it is much better to correct tooth problems
when they are forming than to correct them later. It is better to
get braces in junior high than in college!
We
don’t have space to cover all there is to know about aging and
orthodontics in this article, but this will give our readers the basics
of how the dentition works and hopefully stimulate interest in having
the young horse checked by a qualified dentist to promote health and
prevent problems.
If
you have questions you can contact your dentist or contact
me.
Contact
Us
