Why do horse’s teeth need rasping?

Horses have survived perfectly well for a long time without human intervention so it is sensible to question why it is necessary to perform equine dentistry at all. The answer lies not so much with the horse but with the circumstances in which they now exist.

Horses have evolved to graze on tough grasses for up to 18 hours a day. Their teeth continue to erupt throughout their whole life and they are worn down when they eat. The side to side chewing movement of the jaw results in the upper and lower teeth grinding against each other and this action will wear down the teeth. The greater the lateral movement, the better the teeth will be worn down.

Domestication has brought with it altered feeding patterns and many horses now spend less time grazing and instead are fed hay or haylage alongside energy dense concentrates meaning their teeth are not always worn down as nature intended. 

There are three determining factors that influence whether a horse’s teeth are worn down correctly:

1. The length of time spent chewing: If the horse does not chew for long enough, then the teeth may not be worn down enough.
2. The type of feed being chewed.
   1. When the horse is fed a diet consisting mainly of roughage (grass/hay/haylage) the jaw makes wider movements and the grinding forces are spread evenly over the surface of the teeth. 
   1. When concentrates (grains/nuts) are being chewed much smaller jaw movements are made and the teeth don’t wear evenly.
3. The size and shape match of the teeth and jaw
   1. The cheek teeth of the upper jaw are set wider than those of the lower jaw and with the altered pattern of chewing in domesticated horses, the teeth develop sharp points on the inner edges of the lower cheek teeth (where they cause trauma and ulceration to the tongue) and the outer edges of the upper cheek teeth (where they cause trauma and ulceration to the inside of the cheeks).
   1. Breeding can also influence size and shape of the head, mouth and teeth.

If a horse’s teeth don’t wear evenly it can cause sharp edges and hooks to develop which then rub and catch against the cheeks and tongue. It is these sharp edges that are smoothed when your horse has its teeth regularly ‘rasped’ or ‘floated’. Rasping removes the sharp enamel edges and prevents ulcers and pain caused when the bridle and nosebands push the cheeks against them.

A horse who does not receive regular dentistry is more likely to develop deep ulcers on their tongue and cheeks, sharp hooks, dental overgrowths, wave mouth, step mouth, fractured teeth, gum disease and tooth decay. The teeth are more likely to expire (run out) if abnormalities of wear are allowed to progress unchecked, and therefore may reduce the horse’s lifespan.

Dental problems and oral pain can and do result in poor performance and/or behavioural issues and must be ruled out as a cause of negative behaviours alongside saddle fit, rider crookedness, lameness evaluation, gastrointestinal investigation, etc