What is laminitis?
To understand what laminitis is and how it affects our equine patients, we must first understand the basic anatomy of a hoof capsule. The hoof capsule is the hard, keratinised tissue that extends from the ground to the coronet band (soft ring of tissue around the top of the hoof where the hair starts to grow). Within this hoof capsule lies the pedal bone (also known as the coffin bone). The coffin bone is suspended in the hoof capsule by a series of large and small, interlocked finger-like projections called laminae. These laminae are incredibly sensitive to pressure changes and blood flow alterations, and very intelligently grow and continue to interlock as the hoof capsule grows down from the coronet band to the ground.
Laminitis is the clinical syndrome described by equine health care professionals when there has been a disruption to the blood supply to the laminae, and as a result, the pedal bone is no longer held in the normal position within the hoof.
How does laminitis occur?
There are several different reasons the laminitis occurs, but these reasons can be broadly grouped into a few major categories
Toxic disease: severe systemic toxicity including colic, colitis, retained placentas in recently foaled mares, any illness with severe high fever
Metabolic disease: upsets to sugar and carbohydrate metabolism include grain overload / engorgement, over consumption of sweet green grass, insulin dysregulation disorders (Equine Metabolic Syndrome) or Cushing’s disease (Pituitary Pars Intermedia Disease)
Changes to normal weight bearing: supporting limb lameness following severe injury in one leg, excessive concussive forces or subpar foot care.
What signs can you look out for at home as an owner?
Acute laminitis:
– Shifting or shuffling lameness, reluctant or hesitant gait, unwilling to move
– Heat over the hoof capsule / hoof wall
– Increased or bounding digital pulses
– Increased time spent laying down
– A sawhorse stance – the front feet stretched forward, and the back feet stretched backwards
Chronic laminitis:
– Signs as above
– Stone bruising or bruised soles
– Irregular concentric rings on the feet (altered hoof growth)
– Recurrent hoof abscesses
– Dropped soles or ‘flat feet’
How do we diagnose laminitis?
The first step in diagnosing laminitis is to have a veterinarian attend your horse – they will conduct a full clinical examination and discussion with the owner on the patient’s history. The veterinarian will assess the conformation and appearance of the hoof and then apply hoof testers to the sole of the hoof to assess the response of the patient to different types of pressure applied. We also use this technique to assess for hoof abscesses. The vet will then assess the horse’s gait at a walk or trot (depending on the horse’s comfort) to evaluate where the lameness might be present. This also helps the vet to rule out other causes of lameness which may look similar to laminitis.
In most cases where the veterinarian is suspicious of laminitis, they will perform radiographs (x-rays) on the horse’s foot from several angles, usually under sedation. This allows us to assess how the pedal bone is positioned inside of the horse’s hoof capsule and what degree of damage might be present. The radiographs also provide the attending farrier with an invaluable amount of information on angles and measurements to be able to treat the patient’s hoof in the best way possible. In some cases where we are suspicious of metabolic disease, the veterinarian may discuss further blood testing to rule out EMS or PPID and other systemic causes of laminitis.
Which horses are at risk of developing laminitis?
The types of horses who are at risk changes depending on what type of laminitic process is occurring.
Toxic insults: Horses who are severely ill from another systemic process, mares who have any form of retained placental infection.
Metabolic disease: Overweight or ‘cresty’ horses, ponies, donkeys, geriatric horses with Cushing’s disease (PPID), heavy horse breeds (e.g. Clydesdales) and horses with pre-existing or chronic laminitis issues.
Changes to normal weight bearing: Horses with acute injuries e.g. broken leg, severe ongoing lameness, poor hoof conformation or trimming/hoof care
How do we treat laminitis?
Every case of laminitis will be slightly different, and therefore each case requires its own individual treatment plan. This plan should be developed in conjunction with a veterinarian who has experience in treating laminitis, as well as a qualified farrier who is able to alter the patient’s shoeing / trimming based on radiographs and veterinary recommendations.
One of the most important aspects of treatment revolves around pain relief (most commonly anti-inflammatories are administered routinely). We then need to focus on changing the growth of the hoof to reduce any further laminitic episodes.
Any underlying conditions need to be diagnosed and treated according (metabolic diseases).
My horse has been diagnosed as laminitic – what kind of prognosis am I looking at?
As mentioned above, every case of laminitis is different due to the range of different causes and conditions surrounding each patient. Therefore, it would be unwise to suggest that all cases of laminitis have the same prognosis.
As with most medical conditions, the earlier we achieve a diagnosis, the better the prognosis for almost all laminitic cases. Cases that are caught early with minimal rotation and no underlying disease have the best outcome with regular farrier attendance and ongoing care. The cases that are most worrying to us as veterinarians are the cases that are extremely acute (toxic insults, acute grain overloads), or chronic but severe cases (hoof wall separation is evident on clinical examination). The worst-case scenario is the horse loses all laminae attachments between the hoof wall and the pedal bone, and the horse ‘steps out’ of its hoof (or the hoof ‘falls’ off) leaving an exposed pedal bone. This is a critical emergency and in almost all cases ends in humane euthanasia for the patient.
What is your advice for laminitis in horses and ponies?
The best piece of advice that we at Stabler and Howlett can recommend is to ensure that your horse receives a full veterinary health check at least once per year. At this check, the veterinarian can assess your horse’s overall health and help to rule in or out any risk factors that may be showing early warning signs of laminitis. This also gives the veterinarian the chance to provide preventative health care (health care that reduces the chance of disease later in life) including vaccinations and dental care.
If you think that your horse may be uncomfortable or lame, don’t hesitate to call your local veterinarian for advice and request a consultation if you are concerned. This will allow immediate action for the best case scenario for your beloved four legged vegetarian.
