Laminitis is a common, extremely painful condition that usually occurs in horses, ponies and donkeys. It can occur in other species but on a rarer basis. One in ten horses, ponies and donkeys may be affected every year and while it is a treatable condition, it is estimated that more than 7% of equine deaths are linked to laminitis.

Laminitis affects the sensitive tissues of the laminae which are found in the hoof. These laminae act like Velcro to bond the hoof wall to the pedal bone. The condition causes the laminae to weaken, stretch and become damaged which can result in the pedal bone rotating or sinking under the weight of the horse. In the worst case scenario, the pedal bone can penetrate the sole of the foot. Sadly in these cases the only option is to euthanise the animal and end its suffering.

The condition can occur in any of the hooves but is more commonly seen in one or both front hooves. Laminitis is most commonly associated with obesity, but it can arise in association with endocrine diseases such as Equine Cushings and Equine Metabolic Syndrom (EMS) and those associated with inflammation and stress or be caused by mechanical overload.

Where laminitis is associated with endocrine disorders and obesity, insulin appears to play an important role but the exact circumstances that trigger the laminitic episode are elusive. In cases associated with inflammation such as severe infection,
retained placenta or colic inflammatory responses are triggered throughout the body ultimately resulting in inflammation of the laminae and laminitis.

Where laminitis is associated with mechanical overload it is believed that insufficient circulation or blood supply to the lamellar tissue is associated with continuous or excessive weight bearing. This usually occurs when a horse has an injury or infection causing the horse to favour one leg over the other.

The key symptom of laminitis is lameness, most commonly affecting the two front feet, however, some horses get very mild laminitis that is not severe enough to cause visible lameness but does result in divergent hoof growth rings. When lameness is evident, it is often worse when the horse walks on hard ground or when it turns. Other signs include the horse leaning back onto its heels to take the weight off the painful toe area, shifting weight between feet when resting and increased digital pulses. A horse with laminitis will also demonstrate pain with the use of hoof testers at the point of the frog on its foot.

Overweight horses are much more susceptible to laminitis as obesity can also increase insulin levels in the horse’s blood. It is therefore really important to keep a horse or pony at a healthy weight and monitor any changes. Keepers of native ponies in particular need to ensure that the correct feed regime is followed to keep them healthy and one of the greatest dangers is over feeding. These are animals that evolved on moorland grazing, so rich pasture is not best suited to their systems, particularly if they are given additional feed.

Laminitis associated with infection or sepsis can be prevented by prompt treatment of the underlying disease and the use of ice to cool the feet in at risk equines. Again, prevention measures for endocrine disorder associated laminitis include appropriate treatment of the underlying endocrine disorder, plus reduction of consumption of non-structural carbohydrates found in pasture. Mechanical overload laminitis can be prevented by using frog or frog and sole supports in high risk animals prior to its occurrence.

Laminitis is a medical emergency and any horse or pony displaying symptoms should be seen by a vet so that they can receive treatment as soon as possible. A diagnosis is usually based on the symptoms being displayed, but x-rays may be taken if there is concern that the pedal pone has sunk or rotated or if the animal is not improving despite appropriate treatment. Vets can offer a range of pain-relieving treatments and there are various options for foot support. Box rest and dietary changes are often the most important elements of treatment.

It may take weeks to months for a horse to recover from laminitis. In one research study, 72% of animals were sound at the trot after 8 weeks and 60% were back in work. However, once an animal has had laminitis, it will be at an increased risk of getting it again. Where obesity is the underlying issue, owners must recognise the importance of keeping their animals at a healthy weight rather than risk ‘killing by kindness’ with over-feeding.