Effects of pasture consumption and obesity on insulin dysregulation and adiponectin concentrations in UK native-breed ponies.
Authors: Barnabé, Elliott, Harris, Menzies-Gow
Journal: Equine veterinary journal
Summary
# Editorial Summary Insulin dysregulation and low adiponectin concentrations both independently increase laminitis risk in ponies, yet their relationship to obesity remains poorly understood. Researchers monitored seven UK native-breed ponies over 22 weeks as they grazed freely to reach a body condition score of 7/9, tracking post-oral sugar test insulin levels, insulin sensitivity via tolerance testing, adiponectin concentrations, and pasture characteristics at fortnightly intervals. Post-grazing insulin responses increased three- to fourfold at weeks 14, 16, and 20 compared to baseline (peaking at 103.0 µIU/mL versus 25.0 µIU/mL), tissue insulin sensitivity declined significantly from weeks 2–6 onwards, and crucially, all ponies experienced reduced adiponectin from week 10 onwards, with six developing clinical hypoadiponectinaemia despite normal baseline values. Notably, both poor-quality short grass and lush long grass independently predicted reduced insulin sensitivity, suggesting that pasture management—not obesity alone—substantially influences metabolic dysfunction risk. For equine professionals, this work underscores that grazing conditions warrant as much scrutiny as body weight in laminitis prevention, and that seemingly healthy ponies can develop concerning metabolic markers within weeks on unrestricted pasture.
Read the full abstract on PubMed
Practical Takeaways
- •Monitor adiponectin and insulin response in native-breed ponies on pasture, as obesity-independent insulin dysregulation can develop rapidly; six of seven ponies developed problematic adiponectin levels despite starting with normal baseline insulin
- •Pasture management is critical for insulin sensitivity—avoid both overgrazed short grass and rank lush growth; intermediate pasture quality appears optimal for maintaining tissue insulin sensitivity
- •Ponies can develop insulin dysregulation and laminitis risk factors before reaching obese body condition scores (ID appeared at BCS 7/9), so early metabolic screening is warranted during weight gain phases
Key Findings
- •Body condition score increased from median 5.0 to 7.2 over 22 weeks, with post-oral sugar test insulin significantly elevated at weeks 14, 16, and 20 compared to baseline (p<0.05)
- •Adiponectin concentrations decreased significantly in all seven ponies from week 10 onwards, with six ponies developing hypoadiponectinaemia (<7.9 µg/mL)
- •Both short stressed grass (3/10) and long lush grass (8-9/10) pasture conditions were associated with decreased insulin sensitivity on ITT, while low pasture scores associated with low adiponectin
- •All six ponies with hypoadiponectinaemia demonstrated transient or consistent insulin dysregulation during the study period