Question

Can you share the NSC values of various grass, legume, and grain hays for comparison’s sake?

Answer

Plants that manufacture and accumulate significant quantities of nonstructural carbohydrates (NSC) are often favored by horse owners because of drought resistance, quick regrowth after grazing or hay production, and preference by horses.

While dietary NSC levels do not adversely affect most horses, a small subset of horses and ponies have an intolerance to carbohydrates, which over time can lead to obesity, laminitis, and metabolic problems. For these horses, choosing a hay low in NSC is important for their well-being.

A significant stumbling block occurs in assembling the type of information you’re asking for, as so many factors, apart from the type of grass, can influence the amount of NSC in a hay, including what stage of growth the hay was cut, the season it is harvested, what time of day it was cut, amount of sunlight around harvest time, whether it was rained on after being cut, and how quickly it was dried and harvested. In general, cool-season grasses (orchardgrass, timothy, ryegrass, bluegrass) tend to be higher in NSC and warm-season grasses (bermudagrass, bahia) lower but, again, NSC values depend largely on growing and harvesting conditions.

Equi-Analytical Laboratories, Ithaca, New York, maintains a library of forage and feed profiles that averages the nutritional composition from thousands of samples submitted by hay growers, horse owners, and other interested individuals. For example, in the category of “grass hay,” nearly 17,600 samples have been tested for NSC. Using the Equi-Analytical database, the following general values for NSC are given*: oat hay, 22.1%; barley hay, 19.2%; alfalfa hay, 11.0%; bermudagrass hay, 13.2%; and grass hay, 12.0%.

Tempting as it might be, it would be best to not depend on these general values when selecting hay for starch-sensitive horses. Instead, a representative sample of every batch of hay intended for those horses should be sent for analysis. The analysis is usually inexpensive (less than $35). This may seem somewhat inconvenient, but certain horses require low-NSC hay for optimal health.

*Accessed March 30, 2016.