Nonstructural carbohydrates (NSCs, sugars and starches) cause blood glucose and insulin levels to increase when horses consume them. In horses with insulin dysregulation (ID), this response is often exaggerated, putting them at risk for endocrinopathic laminitis.

Maggie McClendon, MS, Scientist III and Instructor at the University of Kentucky Gluck Equine Research Center, shared recent research she and her colleagues have done on ID horses’ responses to NSCs and meal size.

“We looked at the difference between NSC percentage in feed and the feeding rate itself to determine if it’s the NSC percentage on a feed bag versus the grams per kilogram of body weight of NSC the horse is consuming that may be causing this hyperinsulinemic response in our insulin dysregulated horses,” she explained.

They fed a group of ID and non-ID horses three different feeds over three phases of the study: a low-NSC (7%) pelleted feed, a 14% NSC pelleted feed, and a higher-NSC senior textured feed. Then they took those same three feeds and fed them at three different feeding rates.

“Once we evaluated all of this data, we found that the driving factor is actually the grams of NSC per kilogram of body weight in these individual meals rather than just the overall percentage of NSC in the feed,” said McClendon.

In other words, a “safe” or “low-NSC” feed can still cause insulin spikes if you feed it at a high enough amount. This is important information for not only horse owners but also veterinarians making feeding recommendations for ID horses.

“This study was also really important to look at the individual behaviors of these horses, showing that even within our insulin dysregulated group, we had varying responses to these feeds,” said McClendon. “So just because a feed is safe for one insulin-dysregulated horse, it might not be safe for another insulin-dysregulated horse if that horse is maybe at a more severe stage.”

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  • Alexandra Beckstett is a lifelong horse owner and an award-winning writer and editor. She is the editorial director of EquiManagement and MyNewHorse.com, prior to which she spent 13 years with The Horse/TheHorse.com.

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