Starches, non-structural carbohydrates, and structural carbohydrates… what is the difference, and why are they needed in a horse’s diet? These terms may appear confusing, especially when applied to a feeding program. In reality, these key feed ingredients are important to understand so that a horse receives the nutrition it requires.

Non-structural carbohydrates (NSC) are the simple sugars and starches present in forage and many commercial equine feeds. The simple sugars, glucose and fructose, are the building blocks for starch, which is the connected chain of simple sugars. Enzymes in the stomach and small intestine break down the starch in the feed and reduce it into glucose. Oftentimes, horse owners confuse the presence of starch in the diet as an undesirable ingredient. However, without adequate dietary fiber coming from starch sources, the digestive tract cannot function properly. With an understanding of the influence NSC can have on a horse’s nutrition, managing a horse’s diet to optimize its nutritional intake will be easier than ever.

Allowing non-structural carbohydrates in your horse’s diet is extremely beneficial and will support the horse through its athletic endeavors. Glucose, the simple sugar that is produced from NSC digestion, is an essential energy source for working horses. The amount of required NSC varies by many factors, such as lifestyle, age, gender, body condition, fitness level, metabolism, and current health complications. Most commercial equine feeds already contain the required NSC amount. The primary ingredients in these commercial feeds (corn, barley, and oats) provide as much as 40-60% of a horse’s required daily starch content. However, if a horse has a carbohydrate sensitivity, such as an insulin resistance or Cushing’s disease, the amount in these feeds may do more harm than good, leading horse owners to seek feeds with lower NSC amounts. Feeds that are high in beet pulp, alfalfa, or other forages are typically lower in NSC. For such reasons, it is best to limit a horse’s grain to 0.5% of its body weight to avoid the overconsumption of glucose. If a horse eats excessive amounts of NSC in one meal, its small intestine is overwhelmed by the starch, and the NSC will pass to the hindgut undigested, with a threat to develop complications such as hindgut acidosis, colic, or laminitis.

NSC is also prevalent in forages, making hay and pasture a significant provider of sugars and starches. It is good practice to analyze hay and pasture grasses to assess the NSC, protein, fiber, and mineral content in forage. When analyzing, there may be more sugar and starch content depending on the season when the forage is analyzed, as forage in the spring typically has higher concentrations of sugar and starch. Forage tested in late summer or early fall also has higher sugar and starch concentrations. Mature forages (those that aged before being cut and dried) typically have a lower NSC content because the sugars and starches are diluted by the forage’s high fiber volume. Therefore, feeding mature hays to less active horses or those that need very little NSC content is recommended, as it will prevent the onset of obesity, laminitis, and insulin resistance. Remember, a horse’s energy requirements will not always stay the same! They may vary according to the changing environment (summertime, wintertime, etc.), or by a horse’s growth stage, activity level, or breeding status. Consult a nutritionist or veterinarian to determine the best feeding practice for a horse.

So, what about structural carbohydrates? These carbohydrates are found in the cell wall of plants and serve as an important fiber source for horses. Structural carbohydrates are prevalent in forages and high-fiber feed ingredients, such as soy hulls and beet pulp. This means that feeds that are high in NSC are low in structural carbohydrates, and forages that are high in structural carbohydrates are low in NSC. However, both types of carbohydrates are very valuable energy sources for horses of all lifestyles.

If a horse requires a feed that is low in NSC content, whether that be for low activity, insulin resistance, or something else, Excel Equine®® has Carbolyte®, a low-starch and NSC feed that has controlled calories, making it perfect for horses needing to limit starch calories. It has 20% fiber, 6% fat, and 12.9% NSC content, so even with a low-starch diet, a horse can still meet energy requirements.

NSC and starch are dietary components that are important to consider when feeding horses of any lifestyle of metabolic condition. Most feed companies have nutritionists and knowledgeable people on staff to help you with your questions. If you are seeking more information, please call Excel Equine® at (502) 587-6606.

Excel Equine® Feeds with Low Starch/NSC Contents

Feed NSC Starch
1. Carbolyte® 12.9% 10.5%
2. Enrichment® 13.2% 10.6%
3. Senior Plus® 16.3% 10.3%
4. Trifiber Compete® 16.4% 7.8%
5. Animate®® 16.5% 9.7%
6. Senior HF® 16.5% 9.7%
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