What is NSC?

Non Structural Carbohydrate (NSC) is the term used to describe the sugar and starch content of the feed, ie the digestible carbohydrates. NSC was initially used to describe the sugar and starch in dairy cow feeds. In recent years, it has been recognised that horses are not designed to digest high levels of sugar and starch, and that the NSC levels in horse feed were not being measured.

To measure NSC, and a sample of feed is sent to an accredited laboratory such as Dairy One, and analysed for water soluble carbohydrates (WSC) and starch.

NSC is the sum of the WSC and starch.

When horses digest sugar and starch in the stomach and intestines, and absorb glucose, they also release insulin from the pancreas to help the uptake of glucose into cells, ie the cells are sensitive to insulin. When high levels of NSC are fed, the cells become resistant to insulin, ie the horse is insulin resistant, and blood glucose levels rise. Insulin resistance is associated with metabolic disorders including laminitis, EMS, Cushing?s, colic. High NSC feeds (>12% NSC) are also related to tying up.

NSC levels below 12% are considered necessary to maintain insulin sensitivity, to maintain long term horse health, and to avoid the starch related metabolic disorders. Levels above 12% can be fed, provided that the level of exercise (work) is increased, and the NSC (sugar and starch) to non NSC (oil and digestible fibre) balance of energy sources is maintained (see the Stance Equine Feeding System).

When selecting a horse feed, it is essential that you consider both the exercise level, and the total NSC intake.

Overfeeding with feeds containing >12% NSC, and underworking are some of the major factors contributing to horse ill health "Are you feeding too much NSC ....are you harming your horse with kindness?"