Horses are grazers. In the wild, wandering and nibbling as they go, they seldom have more than a mouthful of grass at a time. In managed environments, we rarely have year-round grazing sufficient to meet our horses' needs. Furthermore, the physical demands we make on our animals in riding and training can make it necessary for us to supplement their grazing with hay and grain.
Hay is the primary food of the domestic horse. Hay may be made from several different types of grass, alfalfa, or a mix of grasses and alfalfa. Hay made from the second and third cutting of a field is generally preferable to hay made from the first cutting as later season hay is finer and more palatable. Green hay is best, but good hay can turn brownish or fade when it is exposed to light. If the inside of a brownish bale is green and smells sweet, the hay is acceptable. Never purchase yellow hay, hay that has a musty moldy odor, or hay that is dusty. Mold spores from hay baled while still wet or damp will show up as very fine dust when a flake of hay is pulled from the bale. Clumps of plant matter in the hay that are grayish or brown also indicate mold. Moldy hay should never be fed to horses. Besides creating a potential for very serious colic, moldy hay can cause respiratory problems. At best, it will go uneaten, and will cost you money and time to replace. If you suspect a problem with the hay, there probably is - keep looking.
Alfalfa is a very high-protein feed. Horses enjoy the taste of it but it should be fed with caution and in limited amounts. Alfalfa can be too rich for many horses and stress their digestive systems. Overweight horses should not be fed alfalfa. If you supplement your horse's diet with alfalfa, be sure to follow the same guidelines as when purchasing hay. If the alfalfa hay (or the alfalfa in your mixed grass hay) has purple flowers, much of its nutrition has been lost. The hay that you purchase should have been stored indoors and kept off the ground. If you do not have a hayloft, stack your hay on wooden or plastic pallets; condensation from dirt or concrete floors can cause mold and mildew on the bottom layer of hay. Hay dust can cause severe respiratory problems in horses. If possible, store your hay in a separate building, away from the horses' stalls.
If you give yourself enough time, you should have no problem finding an adequate winter hay supply. Begin looking for a winter supply of hay in mid-summer; this will give you plenty of time to pass up any hay that is unsatisfactory or questionable. There is nothing more frustrating than trying to find acceptable, affordable hay in February or March, so avoid late-season hay purchases by planning carefully. Plan to feed at least one-half bale per horse per day. Buy enough; it is better to have hay left over when the grass turns green than to be looking for hay at the end of winter. Take the time to learn about the hay in your area, and when you look at hay, take along an experienced friend or neighbor to advise you. Your horse is depending on you for this most important element of his diet!
Oats, sweet feed, commercial grain mixes and pellets can be good ways to supplement a horse's diet. Consult with your veterinarian or a feed specialist if you are unsure about what your horse requires. Once a diet has been established, the best way to ensure good health is to avoid making drastic changes in your horse or pony's feed program. Feed your horse at least twice a day, at the same times every day. Good horsemen are constantly monitoring the body condition of their horses. As you groom your horse or pony, run your hands over its barrel to feel how much flesh is covering the bones. If your horse appears to be getting thin, adjust the amount of feed upward, but do this gradually, over a period of weeks, to avoid illness related to over-feeding.
It is very easy (and very unhealthy) to let your horse become obese. Watch for pockets of fat that develop along the neck, shoulder and buttocks, especially when your horse is not getting much exercise. Exercise is the best way to slim down a horse but remember that exercise should be introduced as gradually as a change in diet. No one would expect you to get into your swimsuit by running a marathon after a long winter on the couch - don't expect your horse to do this either! Begin an exercise program with ten- to twenty-minute sessions, and build up to regular work as your horse gains muscular and cardiovascular strength.
Have salt available to your horse at all times. Feed stores carry inexpensive mineralized blocks that are specially formulated to meet all of a horse's basic needs. These blocks are available in two sizes: large blocks for the pasture and small blocks for the stall.