Lactating mares and exercising horses also need a more concentrated source of energy than most forages can provide. An appropriate starting point for mature horses is to evaluate the body condition. Selecting quality hay can be difficult because there are rarely feed tags to guarantee the nutrient content of the roughage. That doesn't mean owners CANT determine the nutrient content of hay, it simply means owners usually must rely on their visual appraisal of hay to perceive quality. The older a plant at cutting, the more fibrous the hay will be and the LESS digestible the hay will be for the horse.
Green color indicates the hay was cured properly and free of rain.
Green hay is associated with carotene, the precursor to vitamin A, and insures vitamin A will be in ample supply for the horse. Some hays may smell better than others, but no hay fed to horses should smell musty or be excessively dusty. Free of weeds and foreign materials. Plant species differ widely in nutrient content and consequently, so will the hay. After deciding upon the variety to be fed, the most important factor to determine digestibility for the horse is maturity.