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 2 of the latest question and answer installment that you can share with your footcare clients.
Q: Should I be concerned about laminitis when grazing my horses in the fall?
By Kathleen Crandell, PhD
A: Horses are at increased risk for laminitis when grass begins to grow in the spring and provides abundant forage that is high in moisture and carbohydrates but low in fiber. Autumn is also a high-risk time for grazing horses, but for a different reason.
Though pasture growth doesn’t look as appetizing in the fall, with its browning color signaling the beginning of dormancy, this seasonal change triggers plants to produce and store carbohydrates. Waning daylight hours, cool night temperatures, overgrazing, mowing or several dry days followed by rainfall can all lead to increased carbohydrate intake as horses graze. This overabundance of nonstructural carbohydrate (NSC) disrupts the chemistry of the horse’s digestive tract, leading to the release of endotoxins that can result in the onset of laminitis.
A second contributing factor is the rise in adrenocorticotropic hormone, or ACTH, that occurs in all horses as days get shorter and air temperatures drop. This natural change in hormone level may not be a problem for horses with normal metabolism, but for those with a condition like Cushing’s disease or equine metabolic syndrome, higher ACTH levels can trigger increased insulin production. This rise translates into more risk for laminitis in susceptible equines.
You should eliminate or limit fall grazing for insulin-resistant horses or those that have shown signs of laminitis in previous years. Offer low-NSC hay to provide fiber, soaking the hay if necessary to remove some of the water-soluble sugars. When the grass reaches full dormancy and the lower stems are no longer green, it’s probably safe to allow horses back out to graze, at least until forage growth picks up again in the spring.
The use of a buffer primes the hindgut for changes in diet that could lower the pH of the cecum and colon. By stabilizing the pH of the hindgut, there is a decrease in the risk of hindgut acidosis and associated disorders such as colic and laminitis.
Kathleen Crandell is an equine nutritionist with Kentucky Equine Research in Versailles, Ky.
Click here to read part 1 of the Oct. 1, 2020 installment of Hoof Nutrition Intelligence: Does iron play a role in hoof growth and quality?