Managing Equine Foot Problems
By Erica Larson, News Editor • May 01, 2012 • Article #29053
Photo: Erica Larson, News Editor
Managing horses goes hand in hand with managing ailments. While some horse health problems are relatively quick and simple to treat, others are more difficult and tedious. Often, foot problems fall into the latter category. At the 2012 Western Veterinary Conference, held Feb. 19-23 in Las Vegas, Nev., one veterinarian gave some helpful tips on how to best treat difficult foot problems in horses.
"Disorders of the distal phalanx (coffin bone) and adjacent tissues can be difficult to treat because they are confined by and suspended in the hoof," explained Robert L. Linford, DVM, PhD, Dipl. ACVS, a professor in the Department of Clinical Sciences at the Mississippi State University College of Veterinary Medicine. "Successful treatment requires maintaining or reestablishing the capacity of the hoof to suspend the distal phalanx."
The first step, of course, is to attain an accurate diagnosis. Once your veterinarian reaches a diagnosis, he or she can begin treatment and management. Linford discussed several common foot problems horses and owners face and treatment options for those problems.
Subsolar Abscesses--Horses with abscesses located within the hoof capsule typically present with severe or nonweight-bearing lameness, Linford explained. Abscesses in the foot are generally caused by bacteria that gain access to the sensitive tissue between the sole and the coffin bone by way of the bloodstream or a crack or puncture in the sole or hoof. After gaining access to the sensitive tissue, bacteria attract white blood cells that form pus as they accumulate. When more white blood cells are drawn to the area to fight infection, pressure of the accumulating pus separates the sensitive tissue from the hoof or sole to which it is attached. This causes extreme pain as a pocket of pus forms between the sensitive and hard tissues of the foot, Linford said.
The veterinarian can use hoof testers to identify the abscess' general location, Linford said. Then he or she might pare (thin the sole) the foot to try to identify cracks or tracts that will help in both pinpointing and draining the abscess pocket.
When thinning the sole to find the best area to drain the abscess, Linford said, "if tiny red specs appear on the surface of the sole as it's thinned, this indicates the capillaries in the tips of the papillae have been cut and that no further thinning of the sole should be done in that area, because the sensitive tissue that nourishes the sole is still well attached and no abscess fluid has accumulated there. If an abscess is present in the area where the sole is pared, pus will drain before any tiny red specs appear."
Once the pocket has been pinpointed, Linford suggested lightly sedating the horse and possibly using nerve blocks to dull the pain in the foot so the animal is comfortable while the veterinarian drains the abscess. He reviewed with the veterinary audience the best way to thin the surrounding area, expose the pocket, and drain the abscess.
Once the abscess has been drained, he suggested "lightly packing" the abscess hole with a gauze sponge soaked in povidone iodine (i.e., Betadine) before applying a diaper boot to keep the open wound clean and debris-free. Keep the horse confined to a stall, he said, and change the bandage and evaluate the wound every other day, as additional debridement by a veterinarian might be needed to keep the healing process moving. He explained it is extremely important to keep the sole defect completely protected as it heals to prevent debris from entering and causing an infection of the coffin bone.
"When the wound has been dry and free of exudates for several days, the sole can be packed with pine tar-impregnated gauze and a shoe with a full pad applied," he said. He recommended keeping the pad in place for about six weeks to allow suitable sole to develop in the thinned or abscessed areas. The horse can resume full work as soon as the shoe and pad is applied, he said.
Keratoma Formation--Linford explained that keratomas are benign masses (comprised of the protein keratin) that form between the hoof wall and the coffin bone and are almost always found in horses with a history of hoof abscesses. These masses' etiology is unknown, he said, but some veterinarians and researchers believe keratomas result from irritation of some foot structures caused by an abscess. Keratoma-associated lameness typically worsens over time, he added.
Linford noted that in most cases the hoof appears normal outwardly and only occasionally are defects seen on the surface.
Keratomas need to be removed surgically, Linford said, but the prognosis for a full return to function is typically excellent. He reviewed the surgical excision procedure with the veterinary audience before discussing aftercare.
"After surgery, antiseptic or antibiotic-soaked gauze is used to pack the defect, and the foot is (covered) with an impervious padded bandage," he explained. The bandage should be changed every two to three days, he said, and as the wound heals that interval can be increased to three to four days.
The healing process takes six to 12 months, Linford said, and the horse can return to full work as soon as healthy hoof and sole fills the defect.
Quittor--Simply put, quittor is an infection of the coffin bone's collateral cartilage. Linford explained that "a wire cut, wound, puncture, or other direct trauma that seeds the cartilage with bacteria" typically causes the infection.
"Quittor is characterized by pain and swelling in the area of the collateral cartilage with a tract in the skin just proximal (above) to the coronary band, which may intermittently discharge (pus)," he relayed. Affected horses often exhibit lameness, which worsens when the tract closes and pus is trapped inside the hoof, he said.
Conservative antibiotic treatment generally isn't effective in treating quittor, Linford said, so the veterinarians should debride diseased cartilage surgically. In addition to a skin incision above the coronary band, surgery usually also requires creating a drainage hole through the hoof wall in the quarter region.
As with the aforementioned treatments, Linford explained that the hoof wound should be packed with antibiotic-soaked gauze before the foot is wrapped in a sterile bandage. He advised that the bandage be changed every two to three days until "the skin incision has healed and the hoof defect has filled with cornified tissue." Additionally, he recommended systemic antibiotics be administered for 10 to 12 days post-surgery to fight any lasting infection.
"The prognosis is good if the lesion is completely removed," Linford said. "Incomplete excision ... is generally accompanied by recurrence."
Although some equine foot problems are tedious and time-consuming to treat, a basic understanding of the therapeutic options increases the chance for successful recovery. Work closely with a veterinarian to ensure the affected horse receives the proper treatment for each ailment.