Preventing Laminitis in At-Risk Horses

Even though veterinarians and farriers are making progress in developing laminitis treatment techniques and researching the causes of laminitis, prevention is still the No. 1 defense against a disease that plagues all too many horses. During the Sept. 17-18 Laminitis West Conference in Monterey, Calif., Bob Agne, DVM, an equine podiatrist at Rood & Riddle Equine Hospital, in Lexington, Ky., discussed how to recognize individuals that are at risk for laminitis and how to manage them to reduce the risk of the disease.

Several pre-existing conditions can put a horse at risk for laminitis, Agne reported. He noted risk factors and preventive treatments for each, but he cautioned that every case is different. Not all horses will show all clinical signs or respond similarly to preventive measures.

Equine Metabolic Syndrome (EMS)

  • Typical clinical signs: Horses that are easy keepers, are overweight with cresty necks and discreet subcutaneous fat deposits and have high insulin and glucose levels. Horses with EMS are also more likely to show signs of previous bouts of low-grade laminitis.
  • Possible laminitis prevention protocols: Restricted carbohydrate intake, controlled exercise, limited grazing when long hours of sunshine and cool temperatures predominate, levothyroxine supplementation (to assist with weight loss), periodic glucose and insulin testing in spring and fall to check for a hyperinsulinemic state (which predisposes horses and ponies to laminitis), and metformin administration if insulin levels rise above 100 uU/ml.

Cushing's Disease:

  • Typical clinical signs: Cushing's disease is caused by a slow-growing, non-invasive tumor in the pituitary gland and typically only occurs in horses greater than 13 years of age. Unfortunately, laminitis is often the first symptom of the disease, which makes prevention challenging. These horses also exhibit rough, excessively long hair coats, especially in the spring and summer, and can have high circulating levels of adrenocorticotropic hormone (ACTH). Affected horses can also have high levels of blood insulin and glucose, similar to EMS horses.
  • Possible laminitis prevention protocols are: Annual ACTH, insulin, and glucose testing for horses over 13; pergolide medication for horses with high ACTH and hyperinsulemia/hyperglycemia or for horses showing excess body hair and laminitis; diet, exercise, and grazing protocols as per EMS; metformin in some cases.

Prior Bouts of Laminitis

  • Signs of previous bouts of laminitis: distorted hoof capsule, stretched white line, and abnormal foot radiographs showing coffin bone rotation. These changes are indicative of lamellar and vascular (blood vessel) damage that can make subsequent bouts of laminitis more severe.
  • Possible laminitis prevention protocols: Identify and address cause of previous bout, shoe and trim to encourage growth of the sole, and remain vigilant for the earliest signs of recurring laminitis. Additionally, yearly foot radiographs can help identify any changes in the hoof.

Foot Infection and/or Inflammation

  • Clinical signs: Lameness, swelling, draining tracts, heat, and increased digital pulse are evidence of inflammation that can compromise lamellar tissue. If these infections/inflammation are not addressed promptly, subsequent mechanical damage to the coffin bone-hoof capsule bond can result in coffin bone rotation and/or vertical sinking.
  • Possible laminitis prevention protocols: Radiograph feet with chronic draining abscesses or horses whose comfort level doesn't improve in a few days after abscess drainage. A contrast study of the area of infection called a fistulogram can be used to determine the extent of the damage. Addressing abscesses promptly and treating severe ones aggressively are important for preventing lamellar failure. Finally, protecting the wound to avoid re-infection and using a wedge heel and rocker-toe shoeing will help to reduce stress on dorsal laminae.

Contralateral Limb Laminitis

  • Cause: A non-weight-bearing lameness results in an increased risk of laminitis in the opposite foot. This is caused by reduced blood flow within the foot that is forced to bear all of the weight.
  • Possible laminitis prevention protocols: Treat the underlying cause of the initial lameness as quickly as possible; use material to help support the contralateral foot, especially the frog and sole region; remove the shoe if the foot is long, the shoe is inappropriate, and/or lameness is unlikely to improve quickly; and elevate the heel. Finally, monitoring the foot frequently by assessing digital pulses, coronary band health, and venograms are all important for preventing contralateral limb laminitis and detecting it early.

If laminitis does occur, early intervention is key to minimizing the disease's effects. The more owners learn to recognize the warning signs of laminitis (such as the horse shifting weight constantly from one sore foot to the other, standing with the hind feet forward under the belly to unload the front feet, feet that are hot to the touch, and/or bounding digital pulses), the more quickly the disease can be treated and damage to the laminae can be minimized.

The best defense against laminitis is good cooperation between owners, veterinarians, and farriers, said Agne, especially since at-risk individuals can exhibit signs that seem benign or are camouflaged by concurrent lameness. Farriers can be especially helpful because they are in a position to notice changes in the hoof at every shoeing or trimming.

"It's really a team effort in trying to prevent this disease," said Agne.

About the Author

Tracy Gantz

Tracy Gantz is a freelance writer based in Southern California. She is the Southern California correspondent for The Blood-Horse and a regular contributor to Paint Horse Journal, Paint Racing News, and Appaloosa Journal.

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