Confused by Carbs in Horse Feed?

There are lots of terms, and even more opinions, when it comes to carbohydrates in horse feed. Here, we break it down to the basics so you can have a foundation to understand what’s important to your horse!

understanding starch and sugar levels in horse feed

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Types of Carbohydrates in Horse Feed Diets

The topic of carbohydrates for horses has gotten a lot of people asking questions and has created a certain amount of confusion, particularly when comparing carbohydrates in equine diets to human dietary recommendations.  Starches, carbohydrates, sugars, non-structural carbohydrates (NSC) and non-fibrous carbohydrates (NFC), among others, are terms thrown around for equine diets, and all those terms can get very intimidating, when it comes to what these nutrients mean to your horse  and how much your horse needs or doesn’t need. 

Here is a list of each of the common terms, and what they include:

  • Structural Carbohydrates – This category includes primarily the carbohydrates that are part of the cell wall in plants. 
    • This will include the Neutral Detergent Fibers (NDF), primarily lignin, cellulose and hemicelluloses. 
    • These carbohydrates are all fiber sources that give cell walls strength and shape.
    • Some types of fiber analysis, such as the Total Digestible Fiber (TDF) measurement used in human nutrition, will include the structural carbohydrates plus pectins, gums, beta glucans and some polysaccharides. 
    • These are the carbohydrates that are not broken down by enzymes and need to be fermented in the hind gut of the horse.
  • Non-Structural Carbohydrates (NSC) – This includes the sugars and starches, and is a very important group of nutrients for horses because these are the carbohydrates that can be broken down by enzymes and absorbed from the small intestine into the blood stream as glucose and stored as glycogen in the muscles and in the liver. 
    • Ideally, NSCs get absorbed entirely in the small intestine before they reach the cecum and large intestine, where they can be problematic for horses.  When people ask about a “low-carb” diet, they are frequently really asking about a low NSC diet.
    • Water Soluble Carbohydrates (WSC) – This includes ethanol soluble carbohydrates (ESC) which are primarily sugars, both monosaccharides and disaccharides.  WSC will include various oligosaccharides and polysaccharides.  Fructans in forages are included in the WSC.  When looking at a feed or hay analysis report, ESC should be a small proportion than WSC of the NSC.
  • Non-Fiber Carbohydrates (NFC) – This is a different nutrient which is calculated in certain analytical techniques.  NFC is equal to (100-Water-Ash-Fat-Protein-NDF).  NFC is calculated by difference and is not measured by a specific analysis.  NFC will contain all of the organic acids, starch, sugars, oligosaccharides, polysaccharides, beta glucans, pectins and gums.  For this reason, NFC will be a larger number than NSC in a feed or hay analysis report.