WHAT IS FOUNDER OR LAMINITIS?
When a mule or donkey founders, it is commonly
defined as inflammation of the sensitive laminea of the hoof. In
some severe cases, rotation of the pedal bone (within the hoof)
happens, and that may progress to perforation of the sole. The
disease is a local manifestation of a more generalized metabolic
disturbance, and the hoof problems are classified as acute, subacute,
or chronic. It can develop on two feet or all four feet.
The most common causes of laminitis are
ingestion of excess carbohydrate (grain overload) and grazing of
lush pastures. The risk is higher in equines that are overweight
and unfit. Incidence of the acute and subacute forms is higher
whenever there is a flush of new grass.
There are disturbances in the circulation of
the foot, which initially are reversible, probably cause the pain
shown by the equine. The end result, in mild cases, is production
of “laminitic rings”. In severe cases, pedal rotation or complete
separation of the hoof from the underlying tissues occurs. If the
separation occurs rapidly, the pedal bone may sink within the hoof.
In chronic cases, the pedal bone may penetrate the sole just in
front of the frog. The prognosis in severe cases is poor because
the changes become irreversible, and secondary infection is
common. In subacute and chronic cases, the rotation of the pedal
bone occurs relatively slowly. The sole of the hoof tends to become
convex and thickens, and the hoof alters shape to accommodate the
Both donkeys and mules can develop laminitis.
It is important to monitor your equine’s weight to help prevent
laminitis. Acute laminitis constitutes a medical emergency because
pedal rotation can occur rapidly. In some cases, both your
veterinarian and your farrier may be called in to x-ray, diagnose,
and treat the feet with corrective trimming, specialty shoes such as
heart-bar shoes, and leather pads.
Chronic laminitis is one of the most common
causes of lameness in donkeys. It occurs in successive years, when
donkeys (frequently overweight) are turned out in lush pasture. The
signs are usually confined to the feet, and include the heat, (mild
to severe) pain and abnormal gait seen in acute laminitis. Like
obesity, laminitis can be difficult to treat and is better
prevented. Limiting or eliminating pasture turn outs and feeding a
good quality, lower protein hay should prevent most diet-related
cases of laminitis. Occasionally, the stoic nature of donkeys will
allow laminitis to advance long before it may show evidence of foot
pain. Other indications might include occasional hoof abcesses or
a donkey that lies down a lot.
For more information on Laminitis or Founder,
consult with your veterinarian. There are also many books available
on the subject, including;
Donkeys - Miniature, Standard and Mammoth. A
Veterinary Guide for Owners and Breeders by Stephen R. Purdy, DVM
The Merck Veterinary Manual, Published by Merck
& Co., Inc.
U.C. Davis – Book of Horses, A Complete Medical
Reference Guide for Horses and Foals, Edited by Mordecai Siegal