LAMINITIS IN HORSES


WHAT IS LAMINITIS


Laminitis, commonly called “Founder”, is inflammation of the laminae of the foot. The laminae are the folds of soft tissues that attach the coffin or pedal bone within the hoof to the hoof wall. The inflammation and damage of laminae causes extreme pain and leads to instability of the coffin bone within the hoof. In severe cases, this instability leads to complete failure and separation of the laminae resulting in the coffin bone rotating downwards within the hoof wall. This process causes severe damage to the sole and extreme unrelenting pain for the affected horse.


WHY IS THIS DISEASE SO BAD?


Laminitis is the most serious disease of the equine foot and causes changes in the anatomy that lead to long lasting and potentially crippling changes in function. It is actually the second biggest killer of horses after colic! Laminitis can be managed but not cured which is why prevention is so important.


WHAT CAUSES LAMINITIS?


There are many causes of laminitis and research is ongoing in regards to the exact mechanisms that cause laminae separation. Ironically, most causes of laminitis begin at locations and organs well away from the hooves.

  • Obesity (a common predisposing factor in ponies)
  • Over feeding grain or grain engorgement (when a horse gets into a feed shed or bin)
  • Retained placenta in mares after foaling
  • Septicaemic conditions (e.g. colic, enteritis)
  • Lameness which prevents weight bearing on one limb – the opposing limb can develop laminitis
  • Trauma from excess work in unshod horses or trauma to feet following hoof trimming
  • After an episode of laminitis, a horse is much more susceptible to a future episode

 

CLINICAL SIGNS


Laminitis can be both acute (sudden and severe onset) or chronic (inflammation has been present for some time).

Acute Laminitis

  • Forelimbs more frequently affected, all four feet can be involved though
  • Reluctant to move and spend more time lying down
  • ‘Sawhorse’ stance – animals rock their weight back off the more severely affected front feet
  • The horse may shift weight from one limb to the other
  • Hoof wall and coronary band are warm to touch
  • Pain on application of hoof testers if the animal allows the leg to be lifted
  • Palpable increase in pulses to the hoof

Chronic Laminitis

  • Lamanitis ‘rings’ on the surface of the affected hooves that correspond to previous episodes of laminitis
  • Hoof wall appear to be dish shaped with long toes
  • Bulge in the sole corresponding to the rotated coffin bone
  • Horse has restricted movement and will place more weight on its back legs

 

WHO IS MOST AT RISK?


Fat ponies are the most common breed that is predisposed to laminitis. Any horse however that suffers from any of the causes listed above is susceptible to developing the condition. As mentioned, any horse that has had laminitis in the past is more likely to have future episodes as they have fewer healthy laminae remaining to support the coffin bone.


DIAGNOSIS


If you suspect your horse has laminitis, it is important to seek veterinary attention immediately! Depending on the severity of the signs, your veterinarian may choose to do a number of different tests. One of these may be radiographs (x-rays) of your horse’s feet to determine to degree of rotation of the coffin bone within the hoof. This will provide your veterinarian with an accurate baseline measurement against which they can assess the horses’ response to treatment.


TREATMENT


Veterinary attention should be sought as soon as an animal is thought to have laminitis to allow prompt and aggressive treatment. Treatment will depend on each individual case however it may involve a combination of the following.

  • Diagnosing and treating the primary problem (e.g. mineral oil for grain overload) or blood testing for PPID/cushings or insult dysregulation
  • Anti inflammatories
  • Dietary changes – low sugar and low starch feeds such as dry hay, no access to green feed or grains
  • Bedding – move horse to a softer, more comfortable surfaces (i.e. sand stable)
  • Direct support – pads or styrofoam blocks placed over the sole to provide cushioning
  • Farrier – therapeutic shoeing to raise the heel and reduce pain

 

MANAGEMENT


Ongoing dietary management is very important to reduce the risk of another lamanitis episode. Feed hay only until you have sought veterinary attention and advice on what is best to feed your horse. Good quality
hoof care from a professionally trained farrier is also vital. Often your veterinarian will liaise with your farrier to determine the best treatment for each individual animal.


PREVENTION

  • Ensure your horse or pony is fed a balanced diet that is appropriate for their age and activity level
  • Restrict access to lush pastures particularly during the wet summer months.
  • Seek veterinary attention immediately if you think your horse is developing any signs of laminitis.
  • Ensure your horse or pony receives regular hoof trimming from a reputable farrier.

This information sheet is not intended as a substitute for a veterinary consultation. It is recommended that a consultation be arranged with a Veterinarian if you have any concerns with your animal’s health.