Modern equine nutrition has put a large focus on understanding the role of sugar and starch, which combined are referred to as non-structural carbohydrates (NSC), in both healthy and diseased horses.
Non-structural carbohydrates are found in varying amounts in all feed ingredients, apart from ingredients that are solely comprised of fat. The largest source of NSC in most horse’s diets is forage. Pasture, particularly, can be very high in sugars, depending on the weather conditions.
Both starch and sugar are absorbed in the small intestine as glucose. Glucose absorption is countered by the release of insulin from the pancreas to maintain blood glucose levels within normal ranges.
What Horses Require a Low NSC Diet?
Several diseases and disorders are caused or exacerbated by high NSC diets, including:
- Equine Metabolic Syndrome
- PSSM Type 1
- Developmental Orthopedic Disorders
- Hyperactive horses
- Horses prone to digestive upset
Horses who have been identified to have or be at risk of these diseases or disorders should be fed low NSC diets. An example of an at risk horse is the horse with PPID (Cushings). Many horses with PPID also develop Equine Metabolic Syndrome (EMS), therefore, we proactively feed these horses according to the recommendations for a horse with EMS.
Can There be too Little NSC in a Horse’s Diet?
While not all horses require an extremely low NSC feed, there has been a fundamental shift away from feeding “traditional” feeds to horses due to high NSC concentrations.
- Sweet Feed 40 - 60% NSC
- Oats – 54% NSC
- Corn – 75% NSC
- Barley – 60% NSC
Diets providing a balance of energy from highly digestible fiber, fat and a moderate inclusion of NSC support performance of the non-NSC sensitive horse, while minimizing issues related to extremely high NSC diets.
Ultra-low NSC horse feeds may not provide enough glucose for glycogen repletion in the healthy performance horse that is performing at a high level. Glycogen serves as muscle stores of energy that the horse taps into during heavy exertion. Glycogen repletion between exercise events is key to maximizing performance and decreasing the risk of injury due to early onset fatigue.
As fitness increases, a greater proportion of fat can be utilized for energy, sparing muscle glycogen. This has the added benefit of decreasing lactic acid production.
It was long held that horses had limited capacity for digestion and absorption of fat because they do not have a gall bladder. More recent work has found that horses can digest up to 20% of the total diet as fat; however, fat fed at this level has the potential to escape digestion in the small intestine and negatively impact fiber digestibility in the hindgut.
Feeding a high fat (10-12%) performance feed at recommended levels will not increase total dietary fat to the level where fiber digestibility may be impaired; however, care should be taken when supplementing additional fat on top of a high-fat feed.
Feeding an ultra-low NSC product without consideration of fortification of other essential nutrients may not support optimal health and performance and may not provide sufficient energy for recovery between exercise events for performance horses without metabolic disorders.
What is the Right NSC Level in Horse Feed?
Horse feeds are often judged on their appropriateness for a given horse based on the percentage of NSC. While the percent of NSC in a pound of feed is valuable information, it must be taken in context with feed intake. A single pound of a 50% NSC feed would contribute the same quantity of NSC as four pounds of a 12.5% NSC feed (0.5 lb). Percent is not a unit of intake.
When developing a personalized equine feeding plan, we help you determine an appropriate horse feed to complement your hay by taking into consideration any underlying health issues of your horse, the NSC content of the feed and how many pounds of feed you will need to feed to maintain an appropriate body condition score.
Products that we frequently recommend for horses that require a low NSC diet include:
If you’d like help developing a low NSC feeding plan for your horse, we’d love to help!