Of all the domesticated animals, horses seem to be most prone to development of dental abnormalities for a number of reasons.
Their teeth start to protrude through the gums at or soon after birth (the deciduous or milk teeth), and up to 24 of these deciduous teeth will erupt during the first year of life. All of these teeth are replaced during the time up to 5 years of age.
It is easy to see that there are plenty of opportunities for things to go wrong during dental development if there is not regular care and attention paid to the mouth and its associated structures in the growing horse. Horse owners should ensure that their horses have oral and dental examinations, coupled with complete clinical examinations on a regular basis.
These examinations should begin early, and continue for the remainder of the horse’s life. In most situations, dental examinations are best carried out with the horse under sedation. There should be a complete visual and manual inspection of every tooth and the surrounding structures.
All abnormalities and treatments should be noted in a written clinical record for future reference.
Birth to 12 months of age
At or soon after birth, foals will have a total of 16 teeth present – four incisors or front teeth, and 12 premolars or back teeth.
At four to six weeks, four more incisors will erupt through the gum, and at approximately six to nine months the last set of deciduous incisors will erupt. Around the same time, wolf teeth will erupt if the horse is to have them. Wolf teeth are small teeth that are situated in front of the upper cheek teeth. These teeth are vestigial, that is, they serve no purpose and may interfere with bitting of the horse.
It is advisable to remove wolf teeth while the horse is still young as these teeth will eventually fuse with the bones of the skull making extraction far more difficult as the horse gets older. Twelve months is an ideal time to check for and extract wolf teeth.
Dental problems can be congenital, that is present at birth. Examples include brachygnathism or parrot mouth (overbite) and prognathism or sow mouth (underbite). These conditions can sometimes be treated, but to do so they must be diagnosed very early on. For this reason foals should be examined soon after birth.
Twelve months is an ideal time to begin routine dental examinations and treatment as the soft cheek teeth will be wearing each other leading to formation of sharp points. Sharp points on the upper cheek teeth can lacerate the inside of the cheeks, and on the lower teeth can lacerate the sides of the tongue. This causes pain for the horse due to ulceration of the cheeks and tongue. Changes in the way the horse eats due to this pain can affect weight gains, and change the wear patterns of teeth leading to dental abnormalities.
At twelve months of age the first of the permanent cheek teeth erupts so it is a good time to ensure that normal eruption is occurring and to identify any other problems. Dental abnormalities can reduce weight gain by up to 30% which can have long lasting effects on a horse during this critical development period.
From 1 year to 6 years
This is the age that horses will shed their 24 deciduous first set of teeth and up to 44 permanent teeth will erupt through the gums. Common problems during this period are formation of sharp enamel points and deciduous or baby teeth that fail to shed correctly (retained caps).
Early development of more serious cheek teeth changes and malocclusions such as: hooks and ramps (overgrowths of the first or last cheek teeth) waves (uneven grinding surfaces of the cheek teeth arcades) impaction or overcrowding of teeth preventing normal eruption.
These can be identified and treated through examinations every six months. It is also important during this time to ensure all horses have a thorough oral examination and any necessary treatments before beginning their education and breaking in. Failure to do so can lead to the development of behavioural changes associated with oral pain and the negative experiences can have lifelong consequences for both horse and handler.
Article courtesy of VetZone and Equine Veterinarians Australia