Possible Causes of Laminitis

Laminitis, an often frustrating disease, has many different causes that result in the same breakdown of the hoof laminae.

Photo: Nora Grenager, VMD, Dipl. ACVIM

Laminitis, an often frustrating disease, has many different causes that result in the same breakdown of the hoof laminae. Or, as James Orsini, DVM, Dipl. ACVS, of the University of Pennsylvania's New Bolton Center for Equine Veterinary Research, said at the 2012 International Equine Conference of Laminitis and the Equine Foot, held Nov. 2-3 in Monterey, Calif., "All roads lead to Rome."

If "Rome" is the result of laminitis with rotation or sinking of the coffin bone (structural failure of the suspensory apparatus of the coffin bone), then many roads lead there because the equine hoof is what's referred to as a shock organ. "When there's an overwhelming systemic inflammatory response, often secondary to infection or trauma, there's one organ in each species that really gets the brunt of the effects," Nora Grenager, VMD, Dipl. ACVIM, of Grenager Equine Consulting in Middleburg, Va., explained. "In people it tends to be the lung, but in horses it's the hoof."

So that means when horses get sick, their hooves (or specifically, the laminae) take the figurative and literal brunt of the problem.

Grenager outlined the possible causes of laminitis, including:

  • Endocrine disorders, such as pituitary pars intermedia dysfunction (PPID, or equine Cushing's disease) or equine metabolic syndrome (EMS). "Endocrine-associated laminitis is probably the most common type we see," Grenager said. "This is part of the spring pasture-associated laminitis with which most people are familiar. Endocrine disease encompasses horses that are easy keepers and may have EMS, other horses with documented insulin resistance, and horses with equine Cushing's disease."
  • Toxemia, or systemic inflammatory response syndrome (also called SIRS), which is related to grain overload, post-foaling uterine infection, and infectious diarrhea, among other causes;
  • Exposure to black walnut extract, either digested or via bedding;
  • Supporting limb laminitis, where one leg is injured and the weight-bearing supporting limb is affected ("This is the type of laminitis Barbaro had," Grenager pointed out); and
  • Traumatic laminitis, once called "road founder," from overuse, often on hard surfaces.

Other less common causes include allergies, hoof infections, fever, and swelling of the legs. All possible causes are made worse by poor hoof care and obesity, Grenager concluded.

About the Author

Michelle N. Anderson, TheHorse.com Digital Managing Editor

Michelle Anderson serves as The Horse's digital managing editor. In her role, she produces content for our web site and hosts our live events, including Ask the Vet Live. A lifelong horse owner, Anderson competes in dressage and enjoys trail riding. She's a Washington State University graduate (Go Cougs!) and holds a bachelor's degree in communications with a minor in business administration and extensive coursework in animal sciences. She has worked in equine publishing since 1998. She currently lives with her husband on a small horse property in Central Oregon.

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