Pituitary pars intermedia dysfunction (PPID), also known as equine Cushing’s disease, is caused by a tumor formation on the pars intermedia of the pituitary gland and typically occurs in horses older than 15. Clinical signs of PPID include hirsutism, or a long, shaggy hair coat; laminitis; increased secondary infections; and insulin resistance.

PPID is commonly associated with insulin resistance, but research supporting this association is unclear. So researchers at the University of Kentucky’s Department of Animal and Food Sciences recently looked further into the correlation between these two conditions.

Current and previous research has compared horses with PPID to healthy younger adult horses. Since it is known that insulin sensitivity decreases with age, the results of these studies may be invalid.

The University of Kentucky’s (UK) study might have interesting implications for feed companies as well as anyone feeding a geriatric equine. Currently, feed companies are marketing feeds formulated for insulin-resistant horses toward horses with PPID, laminitis, and/or metabolic disorders. However, the results of this study suggest that healthy, normal-aged horses are just as likely to need these types of feed as the aged horse with PPID.

Overall, the study results show that insulin resistance might be a concern for all aged horses, not just horses affected by PPID. The study highlights the importance of treating each horse as an individual when it comes to assessing the horses’ insulin sensitivity.

Kristine Urschel, PhD, assistant professor within UK’s College of Agriculture, Food and Environment, noti