Depending on what study you read, laminitis prevalence in horse populations ranges anywhere from 1.5% to 34%. One of the most frequently cited prevalence estimates, from a study of horses in Great Britain, is 7%. But which figure is correct? Claire Wylie, PhD, MSc, BVM&S, a veterinary epidemiologist at Rossdales Equine Hospital, in Newmarket, England, believes none of them are. So she recently set out to determine a more accurate rate of occurrence, and also to develop a clinical recording system to help veterinarians diagnose laminitis. She presented her findings at the 2013 International Equine Conference on Laminitis and Diseases of the Foot, held Nov. 1-3 in West Palm Beach, Fla.

In the first part of her three-segment study, funded by World Horse Welfare, Wylie and colleagues recruited 28 equine veterinary practices in Scotland, Wales, and England to fill out a reporting form for every lameness case they received from February to April 2009 and January 2010 to May 2011. Based on the responses, these veterinarians diagnosed 37 cases (15.5%) as laminitis and 201 (84.5%) as another form of lameness. In comparing clinical signs between laminitis and nonlaminitis cases, the team determined they were extremely variable, with no one sign present in every case.

In the second part of the study, Wylie’s team sent the same practices a form to complete that would help the researchers calculate laminitis prevalence. They determined the prevalence was approximately 0.5%, meaning 1 in every 200 horses evaluated had active episodes of laminitis. They documented the highest prevalence in the months of January and June, which Wylie noted was interesting because it indicates laminitis is not just a springtime, pasture-associated disease.