Horse feeding sources

There are several feeding sources that, when properly mixed, will easily meet the nutritional needs of horses of any physiological stage.

• Forage: This term refers to all the species of plants that horses and other herbivores eat as their normal source of nutrients, including grass, legumes, and grains (the full plant). After weaning, the young horse must eat forage as a high proportion of its daily diet. Eating forage keeps the gastrointestinal tract functioning. Forage may be offered green or dry (e.g., hay, pellets, cubes, and blocks).

Forage contains different forms of energy (fiber, sugars, and fat), protein, minerals, vitamins and/or their precursors, and some water. These nutrients vary depending on plant species/variety, soil fertilization, season, and plant maturity. Additionally, if the forage is in dry form, the nutrients may vary depending on both the drying and storage processes.

Green forage contains more water (78% – 85%) than hay (15% or less). Thus, the dry matter, which actually contains the nutrients, is more concentrated in hay than green forage. The amount of dry matter in any forage may be calculated by subtracting the water content from the total weight of the forage.

Green, cut forage is turned into hay after drying most of the water content either by exposure to the sun or by any physical means. Horses fed with hay need to drink more water than horses fed with green forage. In addition, horses fed with green forage, which contains more water, spend more time eating to obtain all the required nutrients that are more diluted.

The most common way to offer green forage is by keeping the horse in a pasture, either part-time or full-time. In the pasture, the horse grazes according to its preferences. In addition, grazed forages are more digestible than their hay forms. This is reasonable because a horse selects the young, growing plants in the pasture, which have a higher nutritive value and digestibility, compared to mature plants.

Hay is the most common way to offer dry forage to horses. When hay is not produced on the farm where the horse is housed, customers should obtain thorough information about the hay available on the market (species, dry matter, protein, fiber, length of storage) in order to evaluate the price versus the quality. Alternatively, pellets, cubes, and blocks are other options of dry forage for horses.

Changing the forage source for horses must be done gradually over three to four days, either from green grass to hay or vice versa, or to a different plant species of hay.  This is an important consideration because hay distributors may change the species of hay according to the season.

• Pastures for horses: From the nutritional point of view, a good pasture is the best place for a horse to live because the animal chooses exactly the most nutritious plants, or parts of plants. However, the amount of grass eaten by a horse everyday depends on the plant’s palatability and the dry matter content, as well as the horse’s needs.

From a psychological point of view, the pasture provides a healthy environment for the horse without the stress of being in a stall all day long; thus, the horse has less opportunity to develop bad habits due to boredom/stress. While being in the pasture, the horse learns how to deal with an environment in motion (such as branches being shaken by the wind, birds and squirrels moving around, and rain pouring down), which teaches the horse to be more confident when working. Additionally, if sharing the pasture with other horses, a horse learns how to interact in the herd, that leads to better behavior with other horses.

From a physiological point of view, the horse’s skeleton improves its bone density and becomes stronger because of both exercise and exposure to sunshine (which promotes vitamin D synthesis). In addition, horses in general may benefit by living on moderately inclined pastures that help them develop muscles related to both slow and quick contraction.

From an economical point of view, pastures may produce the cheapest high-quality forage for horses, except if the land price and taxes are very high. Nevertheless, well- managed pastures help increase the land’s value in the real estate market.

A horse in the pasture grazes about 17 hours a day because it takes time to carefully choose favorite plants and chew them perfectly before swallowing. Thus, the horse’s gastrointestinal tract has some foodstuff to digest all the time. Because equines have developed this habit (eating carefully many hours daily) over millions of years, it must be respected when raising domestic horses. Thus, horses kept from good pastures, either in stalls or paddocks, should be fed good quality forage (such as hay) several times a day. When they are fed additional grain, it should be offered in small amounts two times, at a minimum, but three or more times is better.

Ruminants, like cattle, spend about eight hours a day grazing, eight hours ruminating, and eight hours resting. They cut the grass with the tongue or the eight lower incisor teeth (cattle do not possess upper incisors), and swallow it after a little chewing with the molar teeth. When full, they start to regurgitate, chew, and swallow the foodstuff again. Additionally, fiber is fermented by millions of microorganisms in the first stomach (known as the “rumen”), making a very efficient digestive process for obtaining nutrients from forages.

Because horses graze many hours daily and horse pastures recuperate slowly, many people erroneously think that one horse eats the same amount of forage as three cows. Actually, an adult horse of 1,000 pounds of body weight (considered here “A Horse Standard Unit”), eats about 10% to 18% more forage daily than an adult cow of similar weight, which, besides other parameters, shows that cows are more effective in obtaining nutrients from forages than horses. Besides, pastures for horses take longer to recuperate than pastures for cattle. Here is the reason: equines cut the plants shorter (than cows) by using their upper and lower incisor teeth; grass cut shorter (by horses) needs to use stored nutrients to survive while new leaves grow, causing it to take longer to recover.

Due to the different grazing habits of horses and cows, both herbivore species may be kept in good pastures, either mixed at the same time or alternated, to take the most advantage of the grass. The recommended ratio is about one horse to three to four cows.

Note: Zebras (family Equidae, mono-gastric) and gnus or wildebeests (family Bovidae,  ruminant) have grazed and traveled together in the African prairies for centuries. The success of this symbiosis between the two species is based on both the lower proportion of zebras compared to gnus and the two different levels of grass they consume.

The total number of horses (and/or cows) that a pasture will sustain depends on several factors, such as area (acreage), plant species (one or more), fertility of the soil, rain, temperature, and sunshine. As a rule of thumb, when horses are maintained in pastures/paddocks full time and grazing is their most important source of forage (common for broodmares and young horses), a minimum of 1 acre (0.4 hectares) per adult horse of about 1,000 pounds of body weight is recommended. Nevertheless, 1 ½ to 2 acres per horse would be better. Of course, smaller breeds and young horses could use less area and bigger breeds (e.g. Warmbloods, Friesians, and “Draft” breeds) need more area [from the book, The Horse Farm of your Dreams by Diego Bravo].

Although a pasture must provide enough nutrients for horses of all ages (except for salt and some minerals), young growing horses, lactating mares, and horses in training may need supplementation with grain or concentrate feed because of their higher nutritional requirements. Logically, horses kept full-time in the pasture and being supplemented spend less time grazing than non-supplemented horses because grain fills part of their needs.

The horse pasture must contain plenty of nutritious and palatable plants that, ideally, cover the soil. Either one single species of grass or a mix of several species of grasses and/or legumes makes up the pasture forage. Although legumes are more nutritious and usually more digestible than grasses, horses actually prefer to eat grasses. Legumes planted in pastures that are not fertilized with nitrogen, take this nutrient from the air and put it into the soil, which improves soil fertility and, therefore, the grass quality.

Some common grass species for horse pastures are Argentine, Bahia grass, Bluestem, Bromegrass, Callie, Carpet, Coastal Bermuda grass, Kentucky Bluegrass, Orchard grass, Pensacola, Ryegrass (annual and perennial), Tifton varieties, Timothy, and Fescue (not recommended for pregnant mares). Some common legume species for horse pastures are Alfalfa, Clover, and Trefoil.

Selection of any grass and/or legume species, however, is limited by the type of soil, severity of weather within the seasons, and management capability. Therefore, before planting any kind of grass or legume for horse pastures, getting advice from the closest County Agricultural Extension Office or the State University Agronomy Faculty/Department is recommended.

The horse pasture should be kept free of weeds, especially before they seed. “Weed” is the generic word used to define undesirable plants because of their toxicity, non-palatability (e.g., bad taste, having thorns), or low nutritional value. Because equines also eat some weeds when they seed, these seeds go through the gastrointestinal tract to be finally planted in the manure. Then, the weeds gradually invade the pasture, which reduces the nutritious plants for horses.

Because the horse is a selective grazer in the pasture, preferring young, growing plants, horse pastures commonly have areas with mature forage that horses do not eat except if there is no other option. Conversely, because horses keep eating young, short plants from certain areas of the pasture, even digging to reach the plant roots, horses should be rotated periodically to other pastures to maintain the integrity of the plants.

Recently established pastures can be used for horses only when the plants are well developed, even when they are already seeding, although the forage quality is reduced at this time. This keeps the horses from pulling off the young plants from the ground before the roots are deep and strong enough for the pasture to be grazed on; additionally, horses will help spreading the seeds.

Pastures with tender plants, for example during the spring when they are still recovering from the winter, should not be offered to horses with insulin resistance due to the high concentration of sugars and low fiber content. Normal horses can be allowed to graze in these pastures for up to four hours a day and fed additional hay.

The care and culture of a pasture includes dispersing the manure piles with a drag pulled by a truck, four-wheeler, or a tractor; rotational use; fertilization (based on soil testing); irrigations; mowing; and weed and insect control. These activities depend on the weather (season), the plants species, and the soil.  As with selecting grass and legumes, contacting the County Agricultural Extension Office or the State University Agronomy Faculty/Department is also recommended to obtain advice on proper care and culture of the pastures.

Having trees spread out in the pasture provides shade to horses during the hottest hours of summer days. Additionally, it allows for more efficient nutrient recycling in the pasture because the tree roots take nutrients from the deepest levels of the soil, which are not reached by the grass/legume roots. Moreover, after old leaves from the tree fall, they become reduced to simple nutrients by the action of microorganisms, that thereafter become available for the pasture.

• Fresh-cut grass: This does not refer to mowing the lawn or an overgrown pasture, piling the grass with a rack, and giving it to the horses. Doing so has the following risks:
  • Feeding the horses a highly contaminated grass with dirt, bugs, and debris (because of racking).
  • The piles of fresh grass (about 82% of humidity, depending on the plant species) could start fermenting inside by bacteria after a few hours, which may cause botulism to horses and kill them.
  • This provides the horses with a forage of low nutritional quality because it is not being cultivated and harvested to obtain the best feeding material.

What here refers to using ‘fresh-cut grass’ to feed horses consists of having a grass crop technically managed with proper fertilization, harvested at the time of optimum quality (including 26% of fiber, maximum), and feeding the horses within the next 24 hours, either the entire plants or chopped in smaller pieces.

After the grass is being cut in the field, it should be spread on the ground to allow some plant dehydration and to prevent fermentation that may occur within big piles. Because it should not be rained on, when rain is expected, the already cut grass should be moved to a dry, well aired, and covered area. Horses should be fed fresh grass various times a day and any leftovers in the feeders should be removed and disposed before adding new fresh grass. When the long plants of grass (e.g., Pennisetum violaceum, Axonopus scoparius) are chopped to feed the horses, this process should be done immediately before feeding the animals, and any leftovers in the ‘chopping area’ be disposed. This system:

• Is more useful in tropical and subtropical areas (with mild winters).

• Requires choosing the right grass species (e.g., Pennisetum clandestinum, Pennisetum violaceum, Axonopus scoparius, Pennisetum purpureum) that is palatable for the horses and capable of producing high quality forage, ideally, with high yields per hectare.

• Only recommended when having the discipline to cut the grass daily, feed the horses, and get rid of any leftovers (from feeders and storage areas).

The pros of using this system include: high yields per hectare; the possibility of obtaining good quality forage when managed properly; low production costs; the possibility of feeding the horses fresh, palatable, and nutritious grass; keeping the horses busy while chewing the fresh grass, similar to when they graze in the pasture, which also guarantees a slower intake rate than when they eat hay (dehydrated grass).

The cons are: reduced grass growth and production during dry seasons, unless having an irrigation system in place; rainy days make the process of cutting the grass complicated; cutting the grass on rainy days also increases the water content within the plants being harvested and in between them, which goes against the expected dehydration before it is offered to the horses.

• Hay for horses: Hay consists of grass, legumes, or grains (the plant), or a mix of them, in order to improve its overall quality.

• Grass hay: Some common grasses used to produce commercial hay for horses in the United States are Coastal Bermuda grass, Kentucky Bluegrass, Orchard grass, and Timothy. With proper fertilization, these grass species may be cut every three to five weeks (in the most productive season) to produce enough dry matter to contain 7.5 to 12% of protein.

Timothy is very popular for horses due to its palatability and because it usually stays free from mold and dust. Feeding horses Coastal Bermuda grass hay is also popular in the United States, although there is some disagreement about whether this hay may cause colic in some horses. Therefore, horses with a recurrent history of colic should not be fed this hay.  Additionally, coastal hay may become moldy when not being stored properly.

• Legume hay: Alfalfa hay is probably the best legume hay offered to horses because it is rich in high quality protein (from 12 to 16%), energy, and calcium. Besides the traditional hay bales, big blocks of compressed, dehydrated Alfalfa are used for feeding horses in the pasture, especially during the winter when the grass does not grow, and for horses staying in small paddocks. In addition, Alfalfa cubes and pellets are two other ways to offer this legume, which contain around 90% dry matter and similar nutrients and digestibility as hay, although less palatable than regular hay from bales.

Note: Timothy (grass) and Alfalfa (legume) combined in different proportions, is a popular hay for horses offered in the market, known as T&A. Thus, the higher content of protein in Alfalfa increases the total protein offered to the horse.

Clover is a legume offered to horses as hay which, like Alfalfa, is rich in protein and calcium. Perennial Peanut hay is another legume species that is fed to horses. Perennial Peanut is highly palatable, but has slightly fewer nutrients than Alfalfa.

• Grain hay: Some grain plants, such as oats and barley, are also used for hay, usually mixed with grass; these should be supplemented with hay or concentrates that are rich in protein.

Note: To produce good quality hay of any kind and to obtain higher yields, two practices are recommended: a) Soil fertilization based on both soil testing and the specific needs of the plants. b) Bromatological analysis of the plants to determine the time to harvest the best quality product.

• Grains (Cereals): Oats, corn, wheat, barley, and rice are very rich in starch (soluble carbohydrates), which is a form of energy. They are also rich in phosphorus, intermediately rich in protein, and poor in calcium. Dry matter from grains is about 90%. 

Both the entire grain and the bran of these cereals are common sources of energy added to diets for horses worldwide, when forages do not provide enough energy to fulfill the animals’ needs, especially related to physical activity. Protein from grains, however, does not have a high nutritional value because it contains little of the essential amino acid, lysine.

Oats and rice are commonly offered to horses after being rolled, which consists of breaking the husks. Corn is offered to horses in several forms, such as broken into small pieces, flaked, boiled, or kept wet from 6 to 12 hours before. Barley is offered either bruised or boiled. Wheat is commonly offered to horses as bran, which is the outer husk of the grain.

When pure grains (or a mix of them) are offered to horses, soybean meal may be added to improve the quality and the amount of protein. Soybean is a legume, rich in good quality protein, that is available for feeding after removing the hulls of the seeds. Therefore, it is commonly used in concentrates. On the other hand, due to an inadequate amount of calcium in grains, addition of a good calcium source is required to balance their high content of phosphorus.

• Concentrates (or concentrate feed): They are a planned mix of nutritional sources designed to improve horse nutrition that should be used as a supplement to forage. There are several companies that produce concentrates for horses in the United States, with a wide variety of products designed for different purposes. 

The primary sources used in concentrates are cereals, such as corn, oats, wheat, barley, and rice. Therefore, the dry matter of concentrates is around 90%. Other sources in concentrates include soybean meal, dehydrated alfalfa meal, sugar beet pulp, corn oil, molasses, amino acids (lysine and methionine), minerals, vitamins, and propionic acid (used as a preservative). Additionally, some concentrates designed for foals may also contain dried skim milk as a source of protein.

Based on the sources of energy used, concentrates are classified into three main categories:

• Sweet feed: All the ingredients, including starch from cereals, are balanced, mixed, and combined with molasses. Molasses also makes the concentrate more palatable for horses. Vegetable oil is usually added, as well. This type of concentrate is high in energy.

• Pelleted feed with no molasses: All the ingredients, including starch from grains, are processed, balanced, and mixed before they are made into small cylindrical pieces (pellets or nuggets). This type of concentrate contains no molasses. Instead, this type of concentrate is supplemented with vegetable oil and sometimes with sugar beet pulp.

• Pelleted feed with low starch and no molasses: This type of concentrate is recommended for horses that become ´hot´ when being fed starch/sweet sources of energy, and for horses with metabolic problems, such as insulin resistance. The sources of energy used in this type of concentrate are dehydrated alfalfa, highly digestible fiber (e.g., sugar beet pulp), and vegetable oil, among others.

Although concentrates are actually excellent products to improve a horse’s diet, they should never replace forage completely, which is considered the primary food for the equine species. Thus, concentrates should be used as supplements to enrich the horse’s diet and should never exceed 50% of the entire diet (in dry matter), only under strictly supervised conditions.

Note: Horses with gastric ulcers some days object to eat cereals and concentrate feed containing cereals because these increase the acidity in the stomach and, thus, cause discomfort. A concentrate with low starch and no molasses may be a better alternative to be used as a supplement for them.

• Fat: Although grass contains a certain amount of fat (as oil), this important source of energy may also be added to a horse’s diet using vegetable oil (extracted from corn, soybean, rice, or sunflower) or fish oil. Offering cooked flaxseed/linseed is another way to supply some good quality vegetable oil to the horse’s diet, although it requires more labor. Fat is especially helpful as a safe form of energy for horses with high energy requirements, reducing the risk of founder and colic. Additionally, because this energy source does not break down into sugars, it provides the horse with a “calm” amount of energy, that does not make the animal become difficult to control (“hot”).

Feeding fat is recommended for horses that need to gain weight, horses under moderate to high physical activity, and horses over 15 years of age. Feeding fat is recommended for broodmares during the last three months of pregnancy and the first three months of lactation. Broodmares over 12 years of age (before breeding and during their entire pregnancy) also benefit from fat supplementation. A healthy and shiny coat is another advantage of adding fat to a horse’s diet.

Although most concentrates for horses contain 3% to 4% fat, some of them may contain 6% to 7% fat. Special concentrates for high performing horses may contain as much as 10% fat. Oil may be added to low fat concentrates in order to increase calories, but the total amount of fat should not exceed 10% of the concentrate.

• Other horse feed options: Carrots, apples, and turnips are also used for feeding horses (as supplementation) because they are very palatable. These have a high concentration of soluble carbohydrates, diluted by high moisture, so dry matter is just 10%. Thus, these “vegetables” are not very efficient for providing large amounts of nutrients to horses; however, they may be used as a “treat” in order to improve the appetite, reward the horse, or as a regular treat.Sugar beet pulp is a source of energy for horses in the form of fiber (about 13%) and sugars (over 22%). Because of its sweet flavor, sugar beet pulp is accepted very well by horses; therefore, one to two pounds of sugar beet pulp may be added to each meal of grain or concentrate to make it more palatable and to provide some extra energy. Sugar beet pulp is recommended as a complementary source of energy for horses older than 14 years of age.

Maize (the entire corn plant) is an excellent kind of forage for horses, with highly digestible energy and good palatability. Maize may be cut into small pieces before offering it to the horse to make it easier to eat. This source of forage should be managed like fresh-cut grass to make it save to the horses.

Molasses and sugar are two sources of energy that are easily digested by the horse. Cane molasses is commonly added to sweet concentrates for several reasons, such as improving palatability, providing energy, and binding particles. Molasses, however, should not be offered to horses when diluted in large amounts of water because the animal will drink an excess of liquid at one time, thereby “washing” the gastrointestinal tract and preventing the digestion of many nutrients. Sugar may also be added to grains or concentrates as an energy supplement.

Note: As described above, there are many types of horse feed available, some more conventional than others. Therefore, before choosing one or more items, several elements should be considered: nutritional quality, availability in or around the farm, palatability, risks of use, conservation requirements, and price.

• Mineral supplements: Salt (sodium chloride) should be offered to horses, free-choice, to replace what is lost in sweat, urine, and milk (for mares in lactation). Iodized salt or sea salt (the same kinds used for cooking) should be supplied in “salters” placed away from the rain, where the animals may eat the required daily amount, (around 20 grams). Offering a salt block/brick in a salter is another option.

The other macro and micro minerals are usually supplied by offering a mineral supplement mixed with the food, in an amount that covers the needs of each horse. Of course, the mineral supplement should be chosen based on what the rest of the diet is missing.

If offering minerals and salt using these methods is not possible, the other option is to supply them to the horses by means of mineral salt either the powder or compressed into a block/brick. However, this method makes the intake of minerals dependent on the horse’s salt needs.

Note: Read here about How to design the proper diet for a horse