Low % NSC vs. NSC Intake: The Important Differences

The level of non-structural carbohydrates (NSC), the combination of sugars and starches in the diet, is an increasing area of focus when choosing a feed. 

The focus on NSC is warranted because we have discovered that multiple diseases and disorders are caused or exacerbated by high NSC diets, including:

While all horses don’t require a low NSC diet, even healthy horses don’t thrive on super high NSC sweet feeds and straight grain diets that were traditionally fed.

How to Calculate NSC Percentage

The NSC percentage of a feed is the combination of its sugar and starch content. In horse feeds, we are specifically looking at sugars in the form of ethanol soluble carbohydrates (ESC).

NSC = Starch + Sugar (ESC)

This information can usually be found on the guaranteed analysis of horse feeds and other products and should be listed as Dietary Starch (%) and Sugars (%). 

The NSC percentage is the percentage of starch plus sugar per pound. A horse feed that is 10% NSC will provide the horse with 0.1 lb, or 45 grams, of NSC per pound fed.  

What Percentage NSC Feed is Right for My Horse?

The percentage NSC of a given horse feed is one of the most common questions we answer for horse owners! Percent NSC is valuable information, but we need to keep the context of the amount of each product a horse will eat each day when comparing options. The percentage NSC in a product shouldn’t be the only consideration when choosing a feed.

If your focus is minimizing NSC and two products are equal in all other ways, the decision between them is very straightforward. However, we often compare products with different feeding rates.

Example: Essential K® (12.5% NSC) vs Seniority™ Low NSC (10.0% NSC)

Seniority™ Low NSC has less NSC per pound than Essential K; however, they are designed for different applications and do not have the same feeding rate. Essential K® is a ration balancer, designed to deliver essential nutrients with a very low feeding rate, so it is a more concentrated product. Seniority™ Low NSC is a full intake horse feed designed to deliver calories PLUS essential nutrients and, therefore, has a higher daily feeding rate to meet the same minimum essential nutrient supply as Essential K®.

For a 1,000-pound horse, at maintenance (idle), the minimum recommended feeding rates are:

  • Essential K® - 1.0 pound per day
  • Seniority™ Low NSC - 4.00 pounds per day 

Daily NSC intake from these feeds:

  • Essential K®: 1.0 pounds x .125 (12.5 % NSC) = 0.125 pounds NSC intake
  • Seniority™ Low NSC: 4.0 pounds x .10 (10.0 % NSC) = 0.4 pounds NSC intake

In this example, you’ll see that Seniority™ Low NSC contributes over 3 times more NSC to the diet as compared to Essential K®, even though Seniority™ Low NSC has a lower percentage NSC per pound. If you were to feed one pound per day of Seniority™ Low NSC in place of one pound per day of Essential K®, the horse’s NSC intake will be lower, but it will only be receiving 25% of the essential nutrients that Seniority™ Low NSC is designed to supply. These amino acids, vitamins and minerals are key to supporting your horse’s overall health and wellness.

Both are great options for minimizing NSC intake, but the decision to feed one over the other is a function of the overall dietary needs of the horse.

Low NSC for Easy Keepers

For easy keepers, Essential K® paired with forage is the lowest NSC diet option available. These horses do not require additional calories beyond their forage, but they do require essential amino acids, trace minerals and vitamins to support optimal health and wellness. These essential nutrient needs are met by Essential K®.

The majority of NSC in these horse’s diets will come from their forage. Hay testing and managing pasture intake are key to supporting the health of NSC sensitive horses.

Low NSC for the Non-Easy Keeper

Some horses that require low NSC diets will need calories beyond their forage to maintain their body condition. For these horses, Seniority™ Low NSC or Kalm ‘N EZ® supply calories through added fat and fiber to keep NSC intake from the horse feed portion of the diet low.

Forage remains the largest contribution to daily NSC intake in these horses. Managing NSC intake from forage needs to be addressed to best support health.

If you are confused about the best feed choice for your horse with NSC sensitivities, please reach out for a personalized equine feeding plan.

Article By: Nicole Rambo, Ph.D.
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