Hay provides nutrients and fiber in a horse’s and other foragers’ diets and is especially important for grazing animals with minimal pastureland land available. Hay also supplies sugar and while some horses are sensitive to that sugar, other grazing animals like cows are unaffected.
The sugar content of feeds and hay is evaluated based on the starch and ethanol soluble carbohydrate -- also called simple sugars -- content. Measurements are given in ranges because sugar content can vary depending on the season, the climate, the height of the hay, the maturity of the hay and whether or not the hay has already been harvested and begun to regrow.
Timothy hay is considered a medium sugar hay. This warm-season grass measures at the low end of the normal range for ethanol soluble carbohydrates, measuring between 4.7 percent and 10.9 percent. Timothy hay also measures at the low end of the normal range for starch, measuring between 1.5 percent and 4 percent.
Orchard grass is a cool-season grass hay. Because it matures early in the growing season when the weather is wet, it can be susceptible to mold. Orchard grass is similar in starch levels to Timothy hay but can be significantly higher in ethanol soluble carbohydrate, measuring up to 20 percent.