Epidemiological investigation of insulin dysregulation in Shetland and Welsh ponies in Australia.
Authors: Clark Brianna L, Norton Elaine M, Bamford Nicholas J, Randhawa Imtiaz A S, Kemp Kate L, McCue Molly E, Bertin François-René, Stewart Allison J
Journal: Equine veterinary journal
Summary
# Insulin Dysarrythmias in Shetland and Welsh Ponies: What the Numbers Tell Us Insulin dysregulation affects more than three in five Shetland and Welsh ponies in Australia, according to this epidemiological study of 167 ponies that employed dynamic testing methods—specifically oral sugar testing to detect hyperinsulinaemia and insulin tolerance testing to measure insulin resistance—making it one of the largest investigations of its kind in the pony population. Age emerged as a significant factor, with each additional year correlating with higher insulin concentrations at both 60 and 90 minutes post-oral sugar challenge; cresty neck appearance (score ≥3/5) and owner-perceived obesity (visual analogue scale ≥7/9) were likewise strongly associated with elevated insulin levels, whilst males showed lower insulin concentrations than females. Perhaps most clinically significant, both hyperinsulinaemia and insulin resistance independently increased laminitis risk by 4.6 and 3.7 times respectively, and ponies with concurrent pituitary pars intermedia dysfunction faced an 11.75-fold elevation in laminitis odds. These findings validate the value of dynamic testing over resting insulin measurements alone for identifying at-risk ponies, and underscore that neck crest monitoring and owner observations of body condition—practical tools already in widespread use—can help signal which animals warrant formal metabolic screening and stricter nutritional management to mitigate laminitis.
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Practical Takeaways
- •Over 60% of Shetland and Welsh ponies in this Australian cohort had insulin dysregulation; cresty neck and high body condition score are practical visual indicators of metabolic risk in ponies
- •Insulin dysregulation and insulin resistance are significant independent risk factors for laminitis in ponies—metabolic testing should inform preventive lameness management strategies
- •Older ponies and those perceived by owners as overweight warrant metabolic screening; consider PPID testing as PPID status strongly associates with laminitis risk
Key Findings
- •Insulin dysregulation prevalence was 61% (95% CI 53–68%) among 167 Shetland and Welsh ponies tested
- •Age, cresty neck score ≥3/5, and owner-perceived obesity (VASo ≥7/9) were independently associated with elevated insulin concentrations at 60 and 90 minutes post-oral sugar test
- •Dynamic hyperinsulinaemia and insulin resistance were associated with 4.60-fold and 3.66-fold increased odds of laminitis respectively
- •PPID status was associated with 11.75-fold increased odds of laminitis, with female sex and age associated with reduced glucose clearance during insulin tolerance testing