Horses are most content when they
can nibble almost constantly.

Horses are herbivores by design and foragers by nature. They have evolved to utilize grasses
and other forage plants as their primary source of nutrition. Hay generally falls into one of two categories -- grasses or legumes. 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 and clover are examples of legumes. Alfalfa is more commonly fed as hay than 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 and growing horses, lactating mares and performance athletes.  However, not all horses need the rich levels of nutrients present in premium alfalfa.

Although grass hay is generally lower in protein and energy and higher in fiber than legume hay,
this is, in part, what makes it a good choice for many adult horses.  It can satisfy the horse's appetite and provide necessary roughage without excess calories and protein.  Common varieties of grass used for horse hay include:  Bermuda, Brome, Fescue, Oat, Orchard, Prairie, or Timothy.
A horse's protein and energy requirements will depend on age, stage of development,
metabolism and workload. Choosing hay and incorporating it into the ration should be done
with the individual's needs in mind.  A mature horse will eat 2 to 2.5 percent of its body weight
per day. For optimum health, nutritionists recommend that at least half of this
should be roughage such as hay.

Most people buy hay based on how it looks, smells and feels.  That is important, however, it's what's inside that counts.  Ask that one or several bales be opened so you can evaluate the hay inside the bales (do not worry about slight discoloration on the outside, especially in stacked hay).

Choose hay that is as fine-stemmed, green and leafy as possible,
and is soft to the touch.

Avoid hay that is overcured, excessively sun-bleached or
smells moldy, musty, dusty or fermented.
Select hay that has been harvested when the plants
are in early bloom (for legumes)
or before seed heads have formed in grasses.

Avoid hay that contains significant amounts of weeds, dirt, trash or debris.

Examine hay for signs of insect infestation or disease.
Be especially careful to check for blister beetles in alfalfa.

Ask the grower about any potential problems in the region.

Reject bales that seem excessively heavy for their size or
feel warm to the touch. They may contain excess moisture
that could cause mold, or worse, spontaneous combustion.

When possible, purchase and feed hay within a year
of harvest to preserve its nutritional value.

Store hay in a dry, sheltered area
or cover the stack to protect it from the elements.

      Have the hay analyzed by a certified forage laboratory to determine its actual nutrient content. 
This is a good idea, especially if you live in an area with known deficiencies or toxicities.

Remember, horses at different ages and stages of growth, development and activity have different dietary requirements. Consult your veterinarian or a qualified equine nutritionist when formulating
your horse's ration. He or she can help you put together a balanced diet that utilizes hay, grain and supplements in a safe, nutritious and cost-effective way.