If there is one word that will strike fear in any horse owner, it is laminitis. It is an extremely common condition of horses and ponies which can be performance or even life limiting. So what is laminitis and why is it so serious? And can you exercise a horse who is prone to it?

What is laminitis?

Laminitis is the name given to inflammation of the laminae in horses feet. The laminae are velcro like structures that attach the pedal bone (last bone in the foot) to the hoof wall. The pedal bone is surrounded by the hoof capsule, to which it is attached. The deep digital flexor tendon attaches to the bottom of the pedal bone and runs up the back of the leg to facilitate lifting the foot. If the laminae become inflamed and damaged in a bout of laminitis, there is a serious risk that the pedal bone will deviate away from the hoof wall, aided by the pull of the flexor tendon and the weight of the horse.

In the worst-case scenario, the pedal bone can rotate and sink towards the sole of the foot (“founder”); with the risk that it may eventually penetrate through the sole. Any excessive forces, like those associated with exercise can increase the chances of pedal bone rotation in the inflamed foot.  

What causes it?

Laminitis does not have a single cause. The best known casues include endocrine disorders such as Equine cushing’s disease (or Pituitary Pars Intermedia dysfunction, PPID) or Equine Metabolic Syndrome (EMS). Other less common causes in the UK include retained placenta, grain overload or sepsis. A severe non-weight bearing lameness in one limb can also lead to laminitis in the contralateral limb. 

How do we treat it?

The treatment given depends somewhat on the underlying cause. In cases of endocrine disorders, treatment will include drug therapy for that disorder. However, the mainstay of treatment in all cases in the acute phase is box rest, foot support or farriery and anti-inflammatory medication. If you suspect laminitis, you should call your vet for advice and a visit. While you are waiting for the vet, it is advisable to confine the horse as much as possible. If stables are nearby, the horse should be stabled on a very deep bed, with shavings or bedding up to the door; this is so they always have a soft area to stand in. 

Because the laminae are so vulnerable to damage and weakening when inflamed, it is important that we minimise the stress placed on the hoof. We can do little to change the weight of the horse in the short term. So we must ensure that the horse does not move around excessively when the laminae are inflamed; usually indicated by lameness as well as heat in the feet or bounding digital pulses. It should be noted that box rest does not always have to mean a stable. A stable sized area can be created outdoors, which should not include grass, but can have bedding on it instead. This type of restricted zero grazing can be helpful in improving your horse’s mental wellbeing while on strict rest. 

So is exercise ever appropriate?

One of the leading factors associated with an increased risk of laminitis is insulin resistance (IR). Insulin resistance or dysregulation is the term given to the inability of the body to respond appropriately to insulin produced in response to a carbohydrate rich meal. Under normal conditions, the body produces insulin to allow the body to store excess glucose. In insulin resistance, the levels of glucose in the body remain high following a meal; which in turn stimulates the body to produce more insulin. IR animals are at risk not only of laminitis, but also hyperlipaemia, infertility or type 2 diabetes. Ponies with insulin resistance are known to develop Equine Metabolic Syndrome; this is where they tend to deposit fat along the crest of the neck or over the hindquarters and are at an increased risk of developing laminitis. 

Cases of Equine Metabolic syndrome or, in fact any overweight pony, should undergo dietary restriction, particularly in terms of total calorie intake and non-structural carbohydrate intake. It should be noted that not all horses with EMS are overweight and some animals can have both EMS and PPID; so it important that both conditions are considered in laminitis prone animals.

In addition to dietary management and any necessary drug therapy, exercise can be used to improve insulin sensitivity

A recent small study confirmed this by demonstrating that horses that were exercised regularly (25 minutes of walk and trot for 5 days a week), showed improved insulin sensitivity. It is now recommended that any horses who are overweight – or are suffering from EMS – undertake regular exercise to manage the condition. Improving insulin sensitivity will have a big impact on your horse’s overall health and wellbeing. In essence, it is very difficult to manage cases of EMS without exercise. 

Before starting on an exercise program, you should consult your vet and your farrier. They will be able to work together to ensure that your horse is ready to exercise; particularly after an episode of laminitis. They may, in some cases, take radiographs of the feet to determine the position of the pedal bone and to monitor shoeing to ensure that the foot is stable and well balanced. 

What type of exercise is appropriate for your horse?

Ridden exercise is probably easiest to achieve. But not all horses are suitable for ridden work; or in the case of small ponies, have a jockey light enough. There are many other ways that we can exercise our animals, lungeing, long reining or driving are all good ways of working. Other activities such as in hand agility can be helpful in getting moving. In addition to planned exercise, track systems, where resources such as food or water are placed at opposite ends of a fenced track in the field, will encourage ponies to increase the time they spend walking during the day. 

It is important to remember that laminitis can be a recurrent disease

If your pony has suffered from this, it is a good idea to test them for any underlying conditions such as PPID or EMS. Certain medications may help to control these conditions and reduce the risk of further episodes, particularly when used in combination with dietary management and exercise. If you have any concerns about your horse or are considering starting an exercise program, please consult your vet and your farrier who will be able to work together to advise you about your particular case. 

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