Dental Problems in the Older Horse

Caring for our older horse includes many facets of horse husbandry. We are all familiar with feeding hay and haylage to our horses. We are even more familiar with the multiple droppings we collect from the paddock and stable every day.

But did you know the teeth are the only part of a horse’s digestive tract responsible for processing the long-stem forage we feed them into the short pieces of fibre found in droppings?

Functional, pain-free teeth are vital to a horse’s health and well-being, especially the holder horse. In this article, we will look at the challenges facing the ageing horse. We will review how to spot signs of dental disease in any age of horse.

Common Older Horse Dental Problems

The dentition of the horse is referred to as ‘hypsodont.’ Horse teeth are perfectly suited to grazing tough, fibrous, and often gritty grasses and hay. In the younger adult horse, each cheek tooth has a long reserve crown that extends deep into the bones of the skull and lower jaw. It far exceeds the exposed crown visible within the mouth.

As opposing teeth grind together to chew forage, the surface of each tooth is steadily worn away. It is replaced as the reserve crown continues to erupt. Between 20 and 30 years of age, the reserve crown finally runs out. Then the teeth begin to loosen or are shed.

Horses also have tough enamel ridges on the surfaces of their cheek teeth . Those effectively break down long-stem forage into smaller pieces as the teeth grind together. This not only makes the forage easier to swallow but also improves digestion by increasing the surface area of the food. This allows enzymes and gut bacteria to release nutrients.

As horses age, they gradually become ‘smooth mouthed.’ This refers to the loss of the enamel ridges as the cheek teeth come toward the end of their life span. When only a few teeth are affected, most horses continue to chew forage effectively. When multiple teeth are involved, dietary changes might be necessary.

Changes in Teeth

In the younger adult horse, each cheek tooth is almost square in cross section. It can sit tightly against the neighboring teeth like books on a shelf. As the teeth erupt, the reserve crown becomes more circular in cross section, leading to the formation of ‘gaps’ between the cheek teeth. These are referred to as ‘diastema’ (pl diastemata).

A diastema can harbor stale feed, particularly fibrous material. This can lead to infection, gum recession, periodontal disease, and tooth loss.

As in humans, periodontal disease can be immensely painful and might make the horse reluctant to eat forage/hard feed or drink chilled water. Trapped fibrous material can also ulcerate the cheeks and tongue causing further discomfort.

Horses, like humans, can also suffer from dental decay known as ‘caries,’ where bacterial infection causes erosion of the teeth. In some cases, this erosion becomes advanced and can result in fracture of the tooth.

Foreign bodies such as sticks, thorns, or metal objects can be accidentally consumed from the hay or whilst at pasture. This could cause trauma if they become lodged in the mouth.

Dental Checkups

In a healthy horse, the lower jaw moves relative to the upper jaw in a circular motion to help grind forage effectively. In any age of horse, this motion helps prevent the formation of sharp enamel points on the edges of the cheek teeth. If those are left untreated, they can lead to damage to the soft tissues of the cheeks and tongue.

Any form of dental pain will change how a horse chews, exacerbating the formation of sharp points and potentially causing further discomfort.

It is not just the cheek teeth that need checking regularly. Equine odontoclastic tooth resorption and hypercementosis (EOTRH for short) is a disease we have become more aware of in recent years. EOTRH primarily affects the incisors and canine teeth of older horses and causes painful resorption of the tooth roots, inflammation, infection, and loss of teeth. However, in the early stages of the disease, EOTRH can be hard to detect until the pain is so advanced the horse struggles to bite into treats such as carrots or pull hay from a net.

Clinical Signs of Dental Problems

Although clinical signs are easy to recognise if present, dental disease is often well advanced before the horse shows anything to the owner. Or issues might only be discovered as an incidental finding during a routine examination.

Imagine my surprise the day I discovered a large stick wedged firmly across the hard palate of one aged pony that had no clinical signs whatsoever! The stick had been there long enough to cause deep ulcers in the palate and gums. Yet this stoic pony was not even drooling.

Rundown of Clinical Signs

Whilst this article has focused on the older horse, many of the dental problems discussed so far can happen to any age of horse, young or old! This is why annual dental examinations are highly recommended as part of any routine health care plan. For senior horses, six-month examinations might be advised.

Here is a rundown of clinical signs you should be on the lookout with your older horses that can indicate dental issues:

‘Quidding,’ where partially chewed forage/grass drops from the mouth. Observation is key here as field companions love to eat the ‘quids’ before you can find them!
Normal manure/droppings followed by watery faecal liquid, which often stains the hocks and hindlimbs
Long strands of fibre found in the droppings
Colic due to partially chewed forage impacting in the intestine
Oesophageal obstruction known as ‘choke’ caused by the horse attempting to swallow partially chewed forage
Halitosis (bad breath) due to stale food trapped between the teeth and infection
Abnormal chewing action, mouthing, or drooling, which might indicate dental pain, ulceration, or forage lodged between teeth
Swelling over the face or cheeks due to food pocketing or tooth root infection
Weight loss or lack of appetite
Reluctance to consume chilled water or feeds
Reluctance to bite into hard treats such as carrots and apples
Nasal discharge where other infectious causes have been ruled out.

Final Words

Most clinical signs of dental disease in older horses (or any horse!) are related to pain, a physical inability to effectively chew forage, or both. If you suspect a dental problem in your older horse, it is incredibly important to seek veterinary advice quickly to rule out sources of pain or discomfort.