News Notes

Effects of Pasture on Obese Ponies

Giving obese ponies access to pasture was associated with decreased tissue insulin sensitivity, according to a recent study.

“Although elucidating the pathophysiology of insulin dysregulation (ID) and hypoadiponectinaemia was not possible based on the results of the present study, we can conclude that any pony may show decreased adiponectin concentrations when turned out to pasture, regardless of ID status, obesity, or clinical laminitis,” the researchers wrote.

The researchers wanted to know if ponies that developed obesity and had access to pasture developed ID and hypoadiponectinaemia.

They allowed 7 ponies with normal basal and post-oral sugar test (OST) and body condition scores (BCS) of 4.3/9–5.5/9 to graze until they reached a BCS 7/9. Morphometric measures, OST, insulin tolerance test (ITT), plasma [adiponectin], whole-blood expression of receptors for adiponectin, insulin, and insulin-like growth factor 1, and pasture conditions (height and vigour) were measured every 2 weeks.

Median (range) BCS increased significantly (P<0.001) from 5.0 (4.3–5.5) to 7.2 (5.7–7.5) over the course of the study, which lasted for 22 weeks. Basal [insulin] did not change significantly over the study, but median post-OST [insulin] was significantly higher (P<0.05) by week 20 (93.6 [10.0–153.0]
microIU/mL) than when the study began (week 0) (25.0 [10.0–64.0] microIU/mL). Compared with week 0, ITT results were significantly lower at weeks 2 to 6 and 12–20. Adiponectin decreased in all ponies during the study.

Short grasses (3/10) and high lush grasses (8/10–9/10) were significantly associated with low ITT results. Low pasture scores were associated with low adiponectin. BCS was significantly associated with basal [insulin], post-OST [insulin], ITT results, but not adiponectin.

During the study, 6 ponies developed hypoadiponectinaemia, and all the ponies developed ID. ID had a tendency to change during the study, although these changes were not consistent across ponies. MeV

For more information:
Barnabé MA, Elliott J, Harris PA, et al. Effects of pasture consumption and obesity on insulin dysregulation and adiponectin concentrations in UK native-breed ponies. Equine Vet J. 2025 April 21.
https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.14507