Insulin Risks in Australian Ponies

Abnormal insulin metabolism, called insulin dysregulation (ID), is an important component of equine metabolic syndrome, a common endocrine cause of laminitis in horses and ponies. Researchers from Australia conducted a cross-sectional survey of Shetland and Welsh ponies to estimate the prevalence of ID and identify risk factors for the disease.

Testing for high insulin levels, called hyperinsulinemia, and insulin resistance, where the body doesn’t respond normally to insulin, was conducted on 167 pony stallions, geldings and non-reproductive mares. The general health, height, weight, cresty neck score, body condition and signs of laminitis, if any, were also recorded.

The median age of the ponies was 9 years with a median body condition score of 5 (on a 1-9 scale according to owners) and 6 (moderately fleshy on a similar 1-9 scale according to veterinarians).

Test results for more than half (61%) of the ponies indicated they had ID. Increasing age, being female and higher body condition as assessed by the owners were identified as risk factors for ID. Almost 1/3 of the ponies (28%) showed signs of laminitis. The risk factors identified for laminitis included ID, insulin resistance and equine Cushing’s disease (pituitary pars intermedia dysfunction which affected 7% of the ponies). This study highlights the increased risk of ID and laminitis in these pony breeds compared with what is expected among horses, suggesting that increased monitoring of endocrine function would benefit their management.

— Clark BL et al. EVJ 2024;56:281-290

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