What causes laminitis? Is it the same as founder? Should I remove shoes from a horse with acute laminitis? Should I soak his feet? Does laminitis always have devastating consequences?

"Unfortunately, many of these questions do not have definite answers," said Andrew Parks, VMD, head of the Department of Large Animal Medicine at the University of Georgia, during Horsemen's Day, which was held in conjunction with the AAEP Convention, in Seattle, Wash., Dec. 3-7, 2005. "However, over the past 25 years much has been learned about this disease."

"Laminitis is a syndrome in which the epidermal and dermal laminae within the hoof are damaged," Parks said. If the damage is severe, the epidermal layer separates from the dermal layer and the distal phalanx (coffin bone) displaces or rotates in the foot (known as chronic laminitis). Acute laminitis is the sudden on set of clinical signs of laminitis, which include heat throughout the hoof and a reluctance to move often with a rocked-back "sawhorse" stance.

Risk factors include colic, colitis, overfeeding of grain or lush grass, prolonged weight-bearing on a single limb for a prolonged period as with a limb injury, and Cushing's disease.

Horses with acute laminitis can exhibit varied stages of lameness, from barely detectable to being unable to move at all. Their hooves are usually warm and have bounding digital pulses. The disease most commonly affects both forelimbs, but all four limbs can be affected. If a horse shows any of these signs, a veterinarian should be contacted immediately, Parks said.

"Acute Laminitis is not a five-minute emergency, but neither is it a disease that should wait until the next day to be treated," Parks said. "Treatment within the first few hours can make an enormous difference."

Treating acute laminitis within the first few hours, or even before clinical signs are observed (i.e., immediately after catching your horse raiding the grain bin), can reduce the long-term effects of the disease. If a horse is suspected of grain overload, treatment with mineral oil by stomach tube acts as a laxative and tends to prevent absorption of toxic material from the gastrointestinal tract.  Treatment with phenylbutazone or Banamine will decrease the effect of those toxins that are absorbed.

Parks said there is no definitive medical treatment for acute laminitis. Rather, treatments are aimed at providing pain relief, controlling inflammation, improving blood supply to the foot, and preventing coagulation (limited blood flow) in the foot. "It's important to limit/halt the systemic processes leading to laminitis," Parks said. "We want to limit the changes in the foot, and allow the horse to be comfortable."

In a survey taken at the 2004 AAEP Equine Laminitis Research Meeting, the four medications most commonly used to treat acute laminitis were phenylbutazone, acepromazine, flunixin meglumine (Banamine), and dimethylsulfoxide (DMSO). Parks also said that research indicates that icing the limbs before laminitis has developed reduces inflammation in the foot and the severity of laminitic changes.  This is a promising avenue of treatment, which needs to be confirmed in horses that are already showing signs of acute laminitis.

Proper hoof care is also important for laminitic horses. Parks typically removes a horse's shoes and allows it to stand in deep shavings. If more support or relief from pain is needed, he either moves the horse to sand bedding, packs the foot with silicone putty, or tapes Styrofoam blocks to the bottom of the feet. If the horse doesn't respond to this, he recommends using specialized shoes to correct the angle of the coffin bone, which can require raising the horse's heel and changing the breakover of the hoof.

The prognosis of a laminitic horse can be highly variable, according to Parks. "In horses with chronic laminitis, the prognosis for both future athletic performance and survival has been correlated with the degree of rotation," Parks said. The degree of coffin bone rotation that persists despite treatment is a fair evaluation of the horse's return to athletic activity and the need for long-term corrective care.

"Inappropriate application of corrective shoes, premature return to exercise, and not holding to regular shoeing intervals will all negatively impact the success of treatment," Parks warned. "Laminitis is a devastating disease, but not all horses that develop laminitis are devastatingly affected."

About the Author

Chad Mendell

Chad Mendell is the former Managing Editor for TheHorse.com .

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