Search any equestrian-related Facebook group, and you’re bound to come across a dozen of threads about nutrition and the mystifying “NSC” percentage.
NSC stands for “non-structural carbohydrates”, which is mostly referring to the levels of sugar and starch in a commercial grain horse feed. The topic of NSC comes up frequently when discussing low-carb, low-starch diets for horses.
Performance horses rely on sugar, starch and fat for energy. So a diet low in starch and sugar doesn’t necessarily work for all horse types.
Feeds rich in starch aid in glycogen repletion, which can make some horses more excitable, according to Kentucky Equine Research. In some cases, too much starch can lead to metabolic issues like insulin resistance and problems with horses who may have muscle-type disorders like PSSM.
Low-starch grains are generally acceptable for spirited horses and ones prone to gastric issues like ulcers or hindgut acidosis, as a lower NSC rate offers a less-rich option for digestion.
Horse owners can calculate the NSC rate in a commercial horse feed by adding the percentage of sugar and starches listed in the guaranteed analysis on the feed bag. For horses with metabolic conditions, safe NSC percentages are generally 12% or lower, nutritionists say. It’s vital to calculate the percentage on the guaranteed analysis yourself, as marketing on feed products can advertise a “low or controlled” starch diet, but still offer 20% or higher in NSC ranges.
I’s also important to incorporate that percentage into how many pounds of feed is given to the individual horse per day.
But the NSC rate in a grain feed doesn’t offer a full picture of nutrition. Horse owners should also take the levels of starch and sugars of their forage into consideration. That may require having hay tested for nutrient content. One tip is to soak hay to help lower the sugar level.