In our latest veterinary feature, Dr Sarah Davidson, BVMS MRCVS of the Sussex Equine Hospital at Ashington, discusses laminitis.
Laminitis is a painful condition that affects all types of horses at all times of the year but in the spring leading into summer vets certainly diagnose it more frequently and unfortunately, seem to see more severe cases.
This is not a coincidence, one of the potentiating factors of laminitis is lush, green grass, not even in large quantities in some cases. The condition involves inflammation of the laminae, these are structures within the hoof that attach the soft tissues within the foot to the hard, keratinous outer hoof wall. In severe cases, these structures separate and the pedal bone within the hoof capsule ‘sinks’ or ‘founders’ and can also rotate.
Horses that develop pedal bone rotation and sinking in an acute presentation of the disease have a poor prognosis for recovery and long-term survival.
There are three broad causes of laminitis, a horse or pony can suffer from one or more of these at any one time and unfortunately, once a horse or pony has had a laminitic episode they are at constant risk of another and careful management must be employed.
- Endocrine which encompasses both Equine metabolic syndrome (EMS), which is effectively a form of insulin resistance and Cushing’s disease or PPID, which is a disease that many older horses are diagnosed with. This is characterised by dysfunction of the pars pituitary intermedia, an important endocrine gland found in the brain
- Sepsis or infection resulting in the release of toxins into the body can also cause laminitis. Examples would include colitis, complications following colic surgery, retained placenta and also grain overload where abnormal colonies of bacteria in the gut produce toxins
- Overload due to
- Limb overload due to injury of the opposite limb
- Excessive exercise on hard ground
Recognising a horse with laminitis in some cases is very straight forward but in others the signs are subtle and the whole clinical picture must be carefully assessed. Most commonly vets see laminitis in the front feet although it can involve all four feet, one foot and occasionally just the back feet. Typical signs of laminitis include:
- An abnormal stance, rocking the weight back onto the heels to relieve pressure on the more painful toe region. Horses will often also be leaning back over the hind quarters to reduce overall load bearing on the front feet as they are commonly affected to a greater degree
- Reluctance to walk or very slow gait with a stilted and stiff appearance, it may also be noted that the heels are loaded first. Some horses may even lie down and refuse to stand
- Walking on a soft surface is likely to be much preferable. The softer ground fills around the frog and provides support to the internal structures
- Clinical signs are ‘bounding’ pulses on the back of the fetlock, a hoof capsule that is warm to the touch and snatching of the foot when tested at the toe region with hoof testers.
If you see any of the above symptoms and therefore suspect your horse is suffering from laminitis, you should contact your vet immediately for advice. They may well insist that you have a visit as soon as possible as early treatment will result in the most positive outcome. You may be given some ‘first aid’ advice over the phone, these things will include moving your horse from pasture to a stable with a deep shavings bed, administering pain relief in the form of phenylbutazone if you have any available and make sure well soaked hay and water are close by to minimise the need for your horse to move.
When the vet arrives they will perform a thorough clinical exam of the whole horse or pony and a take a detailed history, this will allow them to determine how best to manage your horse in the immediate, short and long term future. In the first instance, treatment will be aimed at making the horse more comfortable using drugs and padding the feet, if shoes can be removed without causing too much distress, your vet may also do this. Strict box rest is a must to minimise movement and therefore continued damage to the laminae, a feeding regime may also be instigated to tackle any underlying systemic disease.
The recovery period can be prolonged in horses that have had an acute, severe laminitic episode and requires a high level of dedication from the owner. Once your horse is comfortable, this may be a few weeks down the line, enlisting the help of a farrier is essential and if radiographs are possible, this is even better. This allows the feet to be trimmed accurately to minimise rotational force from the toe when walking and can also help to guide the farrier if there has been sinking or rotation.
Long term prognosis is very variable between horses and welfare should remain the top priority. Once the underlying cause is identified, every effort should be made using drugs and management changes to get it under control. Some horses may be lucky enough to only have one laminitic episode in their lifetime and others may only manage a few months between flare ups despite their owner’s best efforts, in these cases euthanasia should be strongly considered.
For more information regarding laminitis and Cushing’s disease, visit http://www.talkaboutlaminitis.co.uk/ and https://careaboutcushings.co.uk/ respectively. You can also discuss any questions, concerns or treatment options with your vet.