Horses are most content when they can nibble almost constantly. Although it's not always possible to let our domesticated friends graze to their hearts' content, one way to satisfy their urge to chew and provide essential nutrients is to feed high quality hay. Horse hay is often a mixture of the two. What is readily available and most cost effective generally depends on the part of the country in which you live. Alfalfa is more commonly fed as hay than is clover, although clover may be a component of a mixed hay.
Legumes tend to be higher in protein, energy, calcium and vitamin A than grass hays.
This concentrated source of energy and protein may be an advantage when fed as part of the ration for young, growing horses, lactating mares, and performance athletes. However, not all horses need the rich levels of nutrients present in premium alfalfa. When feeding alfalfa, there is also a need to include a palatable, high phosphorous mineral supplement as part of the ration. This is especially important when feeding young, growing horses. High phosphorous supplements are commercially available just for this reason.