Volume 53, Issue S55 p. 21-22
Free Access

Predictors of laminitis development in non-laminitic ponies

First published: 25 August 2021
Citations: 1


E.J. Knowles1,2; J. Elliott3; P.A. Harris4 and N.J. Menzies-Gow1

1Royal Veterinary College, North Mymms, Hatfield, Hertfordshire, AL9 7TA, UK; 2Bell Equine Veterinary Clinic, Mereworth, Maidstone, Kent, UK; 3Royal Veterinary College, Royal College Street, London NW1 0TU, UK; and 4WALTHAM Centre for Pet Nutrition, Waltham on the Wold, UK.

Email: [email protected]

Background: Quantifying the risk of laminitis requires improvement.

Objectives: To identify morphometric, metabolic or management factors to predict laminitis development in client-owned, non-laminitic ponies.

Study design: Prospective cohort.

Methods: Morphometric, metabolic, and signalment and management data were collected from a cohort of non-laminitic ponies every 6 months for 4 years. Ponies were monitored for laminitis development. Metabolic data included basal plasma concentrations of: ACTH ([ACTH]), adiponectin ([adiponectin]), triglycerides, glucose and an oral sugar test (OST). Serum insulin concentrations ([insulin]) 60 min (T60) after oral administration of Karo™ corn syrup (0.3 mL/kg bwt) and as unfasted basal concentrations were measured (Tosoh AIA-360). Multivariable Cox proportional hazards models were developed separately for morphometric, management/signalment and metabolic data and then combined into two final models (± the OST). Low, medium and high-risk groups were defined based on basal or T60 [insulin].

Results: 374 ponies and 891 pony-years at risk were included. Laminitis incidence (95% confidence interval [CI]) was 4.8 (3.5–6.5) cases/100 pony-years. Laminitis was associated with numerous univariable factors. Significant (P<0.05) factors in the final multivariable models included basal and T60 [insulin], [adiponectin] and evidence of divergent hoof growth. [ACTH] was not independently associated with laminitis. [Insulin] thresholds, centiles of the population and cumulative 4-year laminitis incidence (95% CI) for the risk groups were: basal insulin: low = <21.6 µIU/mL, 0-70th centile, incidence = 6% (2–9%), medium = 21.6–45.2 µIU/L 71st-90th centile, incidence = 22% (10–33%), and high = >45.2 µIU/mL, 91st-100th centile, incidence = 69% (48–82%), and T60 [insulin]: low = <53.4 µIU/mL, 0-60th centile, incidence = 3% (0–6%), medium = 53.4–153 µIU/mL, 61st-90th centiles, incidence = 20% (10–29%) and high = >153 µIU/mL, 91st-100th centile, incidence =73% (52–84%).

Main limitations: Results may not apply to different insulin assays, geographic regions, breeds or management types.

Conclusions: Basal or T60 [insulin] best quantify the risk of laminitis in non-laminitic ponies.

Ethical animal research: The study was approved by the Animal Welfare and Ethical Review Body of the Royal Veterinary College. The research was carried out under a UK Home Office licence (PED1AA054).

Informed consent: Owner consent was obtained for all animals included in the study.

Competing interests: E.J. Knowles is employed by CVS Group and provides diagnostic laboratory services through Axiom Veterinary Laboratories. P.A. Harris is employed by WALTHAM/MARS Petcare UK.

Sources of funding: E.J. Knowles’ PhD was funded by a bequest to the RVC by the Mellon Trust. Study costs were funded by a grant from MARS Petcare UK.