The food which we feed to horses needs to meet seven fundamental requirements. Five of these are:
To understand the other two fundamental requirements, it helps to first understand the normal eating patterns of horses. Horses have evolved as foragers, which means that they eat for a little while in one place, then move on in search of better food (e.g. more tender or nutritious) and eat somewhere else. One often sees this behaviour when the horse is in a large pasture, where they frequently move from place to place. The reason for this behaviour is that they evolved in a landscape where the quality of food was variable (as opposed to the largely uniform grassland which we create in our pastures) so they needed to spend most of their time moving and eating, up to 18 hours per day. This has resulted in two dietary requirements:
In addition to the following, the article Feed & Behavior further explores the relationship of feed and behavior.
Grass and Hay
Grass is the most natural food for horses, as it is what they have evolved to eat. In general, horses will tend to be healthier on a diet which consists mainly of grass than on any other type of food.
Hay is the second most natural food, being rather close to the dried grass which they might find after a hot and dry summer, or dried winter grass. It is less nutritious than fresh grass but good quality hay is a useful alternative when there is not enough fresh grass.
There are a large number of poisonous weeds which can be found in some pastures. Depending on the type of plant eaten and the quantity, the result can be anything from minor to fatal. Some plants can also cause damage the skin or hooves if the horse rolls or walks on them. Consequently, before putting your horse into a pasture, a knowledgeable person should check the pasture for poisonous weeds. As some weeks are visible mainly in spring and others mainly in summer, a thorough walk through the pasture at least twice a year to check for suspicious plants is advisable.
With hay, one faces the same issues with poisonous plants, if the hay is made from a pasture with poisonous weeds. In fact, the situation with hay is potentially more dangerous since horses will instinctively avoid eating many of the the poisonous plants if encountered in a pasture, but when they are mixed in with hay and dried the horses are no longer able to identify and avoid them since they have lost their distinctive smell and appearance. Consequently, one should take special care that one uses hay only from a pasture which is safe or hay that is sourced from a trust worthy source.
The other major risk with grass is that grass which is overly rich in carbohydrates (e.g. spring grass) or nitrates (e.g. fertilised field) can cause laminitis or founder. See the preceding link for more information on how to avoid this. Excessively rich hay may have the same risk, but since hay is made at a time of year when the grass is naturally less rich, this is much less likely.
Another consideration is the quality of the hay. It can contain harmful mold or fungus if it has not been properly dried before being cut, or has gotten wet either prior to or after bailing, or has been stored in plastic bags. Any bales which have mold or fungus should be thrown out rather than used. Hay can also be dusty, ranging from slightly dusty to very dusty, depending on the soil and weather conditions at the time it was made, as well as the way in which it was cut/turned/baled. Very dusty hay should not be used as it can cause respiratory problems in horses. Slightly dusty hay is fine, except for horses which are sensitive to dust. One can soak hay in water to remove the dust, but in this case one needs to clean out uneaten hay each day to stop the wet hay from going off. An advantage of commercial feeds over hay is that in general they are unlikely to have dust, mold or fungus (unless they have been allowed to get wet as a result of improper storage).
Hay Cubes or Bricks
Hay cubes (also known as hay bricks) is hay which has been cut and then compressed into a brick shape. This is a convenient way of storing hay as it uses up less space and can form convenient individual portions. It does tend to be more expensive to buy than baled hay and horses with dental issues may find it more difficult to chew. There have been cases of horse choke reported with hay bricks, but this is uncommon. Aside from these differences, it has much the same advantages and disadvantages as normal baled hay (see above).
Hay pellets is effectively hay which has been ground up, heat treated and converted to pellets. It tends to be more expensive than hay (partly due to the additional processing), but is also more convenient and uses up about a third of the space as medium-density hay bales. As the pellets are effectively hay in another form, it has much the same nutritional value, except for those brands which add minerals or vitamins.
The pellets can be eaten quicker than hay in its unprocessed format, so provide somewhat less occupation and stimulation than unprocessed hay. They also tend to break down quicker in the digestive system, so provide somewhat less value in terms of absorbing stomach acids and protecting against ulcers.
A common problem with pellets is that many horses will try to swallow them without first properly chewing them, resulting in the horses choking. If your horse does this, you should soak the pellets in water for 10 minutes or so before feeding to the horse; this causes the pellets to break down into a soupy mix which the horses cannot choke on. The advantages and disadvantages of soaking are:
Grain and Musli
Grain and musli, when purchased in the form of commercial horse feeds, are high-energy foods which are easily digested. Musli is made from a selection of crushed grains and may have minerals or vitamins added, as well as sugar, fiber and filler.
An alternative to purchasing commercial horse feeds is to buy the grains yourself, which you can feed either individually or combine to make a musli. In this case, you will likely need to purchase a grain crusher and put the grain through the crusher before feeding to horses. The reason for this is that uncrushed grain is an large part undigested by the horse since many of the grains are swallowed whole (rather than chewed) and hole grains simply pass through the digestive system. Most moderate-sized stables use this approach since it reduces the cost of grain feed by 50% to 75% as compared to the commercial bagged feeds. Of course, it takes a bit more time and consequently is less convenient than the commercial feeds, and one needs to invest in the crusher (a few hundred dollars).
Although a bag of grain or musli appears expensive when compared to the same quantity of hay, grain is much higher in energy so the amount of grain required for a horse's daily energy needs is much lower than the amount of hay. Consequently, depending on local prices, they can be substantially cheaper than hay. Many brands of musli have added sugar (e.g. in the form of molasses or beetroot pulp), which further increases the amount of energy.
These products are fed to horses used for sport, not only for the quick energy which they provide, but also because they result in a much trimmer body. Hay and grass are not only bulky in themselves, but also result in additional bulk in terms of digestive gases and food in various stages of digestion or elimination. Consequently, for activities such as racing or jumping, the diet of competition horses is normally high in grain or musli.
As the above discusses, the advantages of these types of feed include convenience, potential cost savings, and a slim torso for competition. In addition, horses which are old, sick or under-nourished can benefit from having their normal diets supplemented by these high-energy foods, especially during the winter when they require additional energy to keep warm.
Against these advantages, there are a number of disadvantages. These energy-dense foods do not offer the bulk, fiber or mental stimulation required by horses. If the foods are fed as a supplement to the traditional diet of hay and straw this is not an issue. However, when such foods from the bulk of the horse's diet, the lack of bulk and fiber can result in various digestive issues (ulcers are common in such cases) and the lack of stimulation can result in stress and the development of undesirable habits (such as cribbing or repetitive movements).
One should also take note that if these high-energy foods are fed in excess, they can lead to carbohydrate overload, causing the serious disease laminitis. As some horses are more prone to this than others, due to breed type or previous medical history, you should consult with your veterinarian before feeding large quantities. If your horse's current diet is already rich (e.g. spring grass) then one should take professional advice before supplementing it with any grain or musli products.
Mash is similiar to musli in that it is a high-energy food made from grain, although mash tends to be a higher energy food than musli. A key difference between the two is that musli is designed to be soaked in water, where it breaks down to form a mush or soup. It is often used as a supplement for old or sick horses, especially during warm weather where it can be made with warm (not hot!) water to help rewarm chilled horses. A further advantage is that it contributes to the horse's water intake (unlike dry feeds), which is a benefit for horses which do not drink enough (a common problem with older horses).
Unfortunately, many horses lift their head away from their feeding bucket while eating, and in the case of mash this can result in them dropping a fair bit on the floor. Furthermore, if they toss their heads while eating (e.g. if startled by a noise), it tends to result in the mash being sprayed on the walls. All such mess should be cleaned up to prevent the growth of mold or fungus. Alternatively, one may wish to feed them from a bucket outside.
There are advantages and disadvantages to high energy foods; see the above discussion on grain and musli for an explanation of these.
The above discusses the main types of horse feeds. Each of these types has a number of sub-types. For example:
In particular, there are many different types of musli, which use different grain and additive mixtures to produce feeds aimed at specific types of horses. For example, one can find musli products which claim to use an optimum mix for: senior (old) horses, foals, pregnant mares, nursing mares, sport horses, show and competition (gives an attractive and shiny coat), complete feeds (intended to be used as the sole food rather than a supplement) and so on. These speciality foods vary in terms of the ratio of macro-nutrients (e.g. proportions of protein, fat, complex carbohydrates, simple carbohydrates), the types and amounts of micro-nutrients (minerals and vitamins) and the source used (e.g. fiber from beet-root has different characteristics than fiber from alfalfa in terms of speed and ease of digestion).
Unfortunately, different manufacturers have different and conflicting views on what these specific requirements are. For example, senior food from one manufacturer will use higher than normal amounts of sugar because it is an easily digested energy source for older horses with reduced digestive capability, while senior food from another manufacturer will use lower than normal amounts of sugar to avoid problems of Cushings disease and insulin resistance which are more common in older horses. Given these opposing and conflicting approaches, it can sometimes be hard to determine if a speciality food is actually better or worse for your horse. Consequently, it is advisable to discuss with a veterinarian your individual horse's condition and requirements before deciding on which of the speciality foods is most suitable for your specific horse.
Fruit and Vegetables
Although large amounts of fruit or vegetables are not a natural diet for a horse, small amounts as treats are suitable. Prior to feeding, they should be cut into small irregular pieces, as round pieces (e.g. a small whole apple) can become stuck in the throat and cause choking.
Acceptable fruits include: apples, bananas (peeled), pears. Acceptable vegetables include: beetroot, carrots, celery, parsnips, swede and turnip.
Do not feed onions, potatoes, rhubarb, tomatoes. Do not feed sour fruits. Be careful of large amounts of sweet fruit as excessive sugar can lead to weight gain, laminitis, or blood sugar imbalance. If a fruit or vegetable is not on the acceptable list, do not feed to your horse without first consulting a veterinarian.
You should be consistent in what you feed your horse. If you travel with your horse and are unsure that you will be unable to get the same type of food on your trip, try to take enough of his food to feed him until you return, or make arrangements to obtain his normal food during the time away.
If you need to change your horse's diet, you should do so gradually. Likewise, if you are getting a new horse and plan to change his diet, it is wise to obtain a quantity of his old food so that you can gradually change him over. When changing a horse's diet, you should carefully watch his behaviour and activity to ensure that there are no adverse results (e.g. colic, lamintis, food allergies).
Determining the best diet for your horse is an important and serious matter, particularly if it is weak (old, very young, sick, dental issues) or has a weight issue (over or under) or has a food related medical history (colic, laminitis, allergy, insulin resistance, etc.). It is advisable to develop a suitable diet with a veterinarian or equivalent professional, based on a knowledge of your individual horse's specific requirements and intended use. A diet which is as natural as possible (e.g. grass) is generally the healthiest for the horse, unless it has specific requirements for other types of food.