CEPS/Veterinary Extension
2938 Vet. Med. Basic Sciences Bldg.
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907

By Lydia Miller
Information Specialist
University of Illinois
College of Veterinary Medicine

What do founder, a sole bruise, a foot abscess, and a broken coffin bone all have in common? A horse with any one of these conditions can suddenly become very lame, have hot feet and bounding pulses in the feet, and be sore in one particular area of the foot. According to Dr. Tom Goetz, an equine veterinarian at the University of Illinois College of Veterinary Medicine at Urbana, one way to begin to figure out which condition the horse has is to decide if one or more than one foot is affected.

"Laminitis and often times sole bruises affect more than one foot, whereas a foot abscess or broken coffin bone is more likely to occur in just one foot," classifies Dr. Goetz.

Besides hot feet and bounding pulses in the arteries at the back of the fetlock, laminitic (foundered) horses usually have a very characteristic stance and walk. If only the front feet are affected, as is usually the case, these horses will extend their front legs out ahead of their body while bringing their hind legs up underneath their body to help take some of the weight off the front end. They will be reluctant to move, especially in tight circles, he says. If persuaded to walk, they may land heel first, slapping the toe on the ground.

"There are numerous causes of founder," points out Dr. Goetz. "Some of the more common ones are gastrointestinal upset (such as colic or diarrhea), grain overload, and retained placentas." No matter what the underlying cause, all lead to an initial decrease in the blood supply to the foot. This in turn leads to damage of the structures that link the coffin bone and hoof wall, allowing the bone to rotate or sink away from the hoof.

Treatment involves correcting the condition that precipitated the laminitis and treating the laminitis itself. The latter is usually accomplished with pain-killers, frog support, and prolonged stall rest. Recovery can be followed by taking X-rays when the condition is first noticed and comparing them to X-rays taken every three to five days for several weeks.

The second lameness that often involves more than one foot is sole bruises. Horses can develop these from poor foot conformation (flat feet), poor shoeing (shoes or pads that apply excessive sole pressure), or work or turnout on hard, uneven ground (frozen winter paddocks). After localizing the pain to the foot, your veterinarian may diagnose this condition by paring away the sole on the bottom of the horse's foot in the painful area until a bruise (or abscess) is found. An abscess will be an area where pus has replaced normal hoof, whereas a bruise may be a blood-filled area, if the condition has been around a while.

After applying a topical antiseptic, bandaging the site, and putting the horse on pain-killers, the next step is determining how the horse bruised its feet and preventing this from happening again. If poor footing seems to be the culprit, then either the footing should be changed or the horse shouldn't be worked or turned out on that footing. However, if your horse is found to be flat-footed, then therapeutic shoeing to keep the sole from contacting the ground may be in order. This may involve a beveled shoe (so that the inner part of the shoe that touches the sole is ground away), employing pads between the hoof and shoe (to raise the sole farther away from the ground), or attaching a metal plate to the bottom of the shoe.

A condition that resembles a sole bruise except that it usually occurs in only one foot is a foot abscess.

"A horse with a foot abscess can be absolutely sound one day then fracture-lame the next, such that the possibility of a fracture must be considered," notes Dr. Goetz. Any horse that refuses to stand or use a limb should be examined by a veterinarian immediately.

A foot abscess is a localized bacterial infection under the hoof wall or sole. In most cases, no one knows why or how the condition developed. However, horses with poor horn quality to their hoof seem to be predisposed to foot abscesses, especially during muddy conditions brought about by repeated freezing and thawing of the ground in late winter. A badly placed nail -- one that is too close to sensitive tissue -- can also cause a foot abscess by introducing bacteria into the foot.

A foot abscess must be opened up and drained in order to heal. Your veterinarian may have you soak the foot for a few days, then plug the area with
antiseptic-soaked gauze and bandage the entire foot. A tetanus booster is important unless the horse has received one within the last six months. Also critical to recovery is stall rest in a clean, dry, mud-free area until the site is dried out and hard.

When the foot has healed to this stage and the horse is no longer lame, Dr. Goetz says it can usually be put back into work. However, if there is no improvement after seven to 10 days, have your veterinarian recheck the foot to ensure that complications such as a secondary bone infection have not set in. This should include radiographs in these circumstances to rule out a fracture.

The final foot condition is a fracture of the bone inside the hoof, the coffin bone. X-rays are required to diagnose this condition. Unless the joint between the coffin bone and the bone above it is involved, the horse has a good chance of returning to work once the break has healed.

A broken coffin bone must be immobilized just like any other fracture, and its location inside the hoof provides a good start. Sometimes all that may be required beyond this is a "bar" shoe (one that goes across the heels but does not touch the frog) with toe and heel clips to prevent the hoof from expanding outward. More severe cases may require either a cast-like material to be applied around the hoof, a surgically, depending on the fracture type. Recovery from a fractured coffin bone usually requires six to 12 shoe with metal walls to be bonded to the hoof, or screws inserted months.