Background: Obesity and insulin dysregulation (ID) predispose horses to laminitis. Determination of management practices or phenotypic markers associated with ID may benefit animal welfare.
Objectives: Determine ID status of a population of Finnhorses using an oral sugar test (OST) and compare phenotypes and management factors between ID and non-ID Finnhorses.
Animals: One hundred twenty-eight purebred Finnhorses ≥3 years of age.
Methods: Owners were recruited using an online questionnaire regarding signalment, history, feeding, and exercise of their horses. Selected contributing stables within a predefined area were visited. Phenotypic markers of obesity and the weight of each horse were recorded. After fasting overnight, horses received 0.45 mL/kg corn syrup PO. Serum samples before and at 60 and 90 minutes after syrup administration were analyzed for insulin by chemiluminescent assay. Horses met ID criteria if insulin concentrations were ≥33 μIU/mL at T0, ≥66 μIU/mL at T60 or T90 or some combination thereof. Associations between phenotypic markers, feeding and exercise variables, and ID were examined using mixed effects logistic regression modeling.
Results: Several phenotypic markers of obesity were significant on univariable analysis but in the final multivariable model, only obesity (body condition score ≥8) was associated with ID (P = .04). Over half of the horses (60% [95% confidence interval (CI), 51%-68%]) were considered overweight or obese whereas 16% (95% CI, 10%-23%) were classified as having ID.
Conclusions and clinical importance: Because obesity is associated with ID in cold-blooded type horses, objective monitoring of phenotypic markers by owners may be beneficial for health outcomes.
Keywords: EMS; OST; equine; laminitis.
© 2020 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.