Hoof Nutrition Intelligence is a twice-a-month web segment that is designed to add to the education of footcare professionals when it comes to effectively feeding the hoof. The goal of this web-exclusive feature is to zero in on specific areas of hoof nutrition and avoid broad-based articles that simply look at the overall equine feeding situation.
Below you will find Part 1 of the latest question and answer installment that you can share with your footcare clients.
Q: Are certain laminitis issues related to certain hormones?
By Catherine Whitehouse, M.S.
Horses and ponies with insulin dysregulation produce too much insulin in response to dietary carbohydrates. Over time, this often leads to laminitis.
Though researchers can document these insulin spikes, they don’t know why they occur. As a result, researchers recently looked closely at a specific hormone that might help unlock the insulin-laminitis mystery.
This hormone, glucagon-like peptide-1 (GLP-1), is released from the intestinal wall during the digestion of certain carbohydrates and helps stimulate pancreatic insulin production. Horses prone to laminitis have shown greater plasma GLP-1 in response to being fed grain, but researchers didn’t know whether GLP-1 was actually responsible for the extreme insulin response. As a result, they set out to block the GLP-1 receptors to determine if this hormone plays an important role in excessive insulin excretion in horses diagnosed with insulin dysregulation when fed a high-glycemic meal.
Five mature and obese ponies known to have insulin dysregulation were given a feed challenge. They were given a GLP-1 receptor-blocking peptide, which is known to block the activation of the receptor in several species and with in vitro studies of equine pancreatic cells or tissues. The ponies were fed a high-starch meal containing micronized corn, soybean hulls and alfalfa chaff. Insulin, glucose and GLP-1 levels were measured in blood samples.
This study confirmed that high levels of GLP-1 in horses with insulin dysregulation contribute to excessive insulin production. Blocking the receptor partially reduced insulin production in response to a high-starch diet. However, it is not known whether the amount of receptor blocker was optimal, as it might be possible to achieve an even greater blocking effect based on more study with varying doses.
As it stands, GLP-1 receptors are a potential therapeutic target for preventing laminitis.
Every scientific study takes us one step closer to understanding the role of insulin in laminitis. Until a cure is found, management remains a key strategy for horses with insulin dysregulation or those that are predisposed to it.
Key management strategies include:
1. Keeping your horse in moderate body condition, which means being able to easily feel its ribs without necessarily seeing them. Horses are individuals, so some leeway here is necessary, but horses should not be roly-poly, as this may make them more susceptible to metabolic issues. Be especially mindful with horses known to be easy keepers, such as Morgans, Arabians and many stock-type breeds. Refer to the Henneke body condition scale if you’re not comfortable recognizing moderate body weight. Using that scale, horses should be a 5 (moderate).
2. Feed the diet your horse requires. Easy keepers with a casual lifestyle might do well on good-quality forage with only a vitamin and mineral supplement. Horses should be fed energy-dense concentrates, like commercial feeds, to help fuel growth, performance or lactation and to provide key nutrients for physiological processes that are not applicable to an idle easy keeper.
3. A well-formulated vitamin and mineral supplement will round out the nutritional needs of horses fed all-forage diets.
4. Exercise your horse 5-6 days a week, if soundness allows. Researchers believe at least 30 minutes of exercise with an elevated heart rate can help keep metabolic problems from developing.
5. Use of omega-3 fatty acids, such as marine-derived sources, can help with insulin sensitivity. Feeding a hindgut buffer can support health of the cecum and colon.
6. Enlist the help of a knowledgeable veterinarian and an equine nutritionist. These professionals can help you make key decisions about health and management.
Catherine Whitehouse is an equine nutritionist with Kentucky Equine Research in Versailles, Ky.
Hoof Nutrition Intelligence is brought to you by W.F. Young Co. (Absorbine). 
Like many significant achievements, Absorbine® grew out of humble beginnings—and through the tenacity of someone willing to question the status quo. In this case, it was a young woman in late 19th-century Massachusetts: Mary Ida Young. Her husband, Wilbur Fenelon Young, was an enterprising piano deliveryman who relied on the couple’s team of horses to make deliveries throughout the Northeast. Inspired by Mary Ida and Wilbur’s vision, Absorbine® has continued to add innovative products throughout the years — products used every day by horse owners around the world. Which is why, since 1892, we’ve been The Horse World’s Most Trusted Name®.
Click here to read Part 2 of the Nov. 1, 2018 installment: Could my overweight horse have an insulin problem?
Click here to read more installments of Hoof Nutrition Intelligence.