Each type of hay has certain characteristics that you should be familiar with.

Timothy Hay

Timothy Hay

Timothy hay is one of the most popular hays fed to horses. It can be quite expensive, depending on whether it has to be shipped long distances. Timothy must be harvested in the pre- or early-bloom stage to ensure a high nutrient content. The first cutting usually has a higher weed content, and quality decreases after the second cutting, so the second cutting is usually the best to feed.

Bermudagrass Hay

Bermudagrass Hay

Bermudagrass hay is used mostly in the southern United States. Common bermudagrass does not grow tall enough for hay production, but coastal bermudagrass can be used. The same stand of grass can be cut four or five times a year. It is as nutritious as timothy hay, and its value can be increased by growing it with a legume.

Oat Hay

Oat Hay

Oat hay is an excellent feed for horses. The choice between alfalfa and oat hay depends on price per unit of energy or protein and the type of horse being fed. Depending on the area of the country in which it is grown, oat hay can be low in protein and contain only marginal calcium, phosphorus, and carotene.

Alfalfa Hay

Alfalfa Hay

Alfalfa hay is one of the best hays fed to horses. Several characteristics of alfalfa make it an excellent hay for horses.

• It is highly palatable.

Most horses will readily consume alfalfa hay. However, because of its high palatability, intake must be restricted to keep horses from overeating and becoming colicky.

• It is high in energy.

Alfalfa hay has 120 percent more energy per unit in weight than oat hay. Therefore, it takes less hay to meet a horse's nutrient needs when feeding alfalfa hay. However, the high-energy content may lead to overfeeding and to a fat horse.

• It is high in protein.

Alfalfa hay is high in good-quality protein. Crude protein values can be as high as 18 to 19 percent. People once thought that feeding alfalfa hay to horses caused kidney damage because of increased urination and ammonia production. We now understand, however, that excess protein in alfalfa is converted into energy compounds, and the nitrogen produced in this conversion must be eliminated as ammonia.

• It is a good source of vitamins and minerals.

If cured correctly, vitamin C content will be high. The calcium:phosphorus ratio is about 6:1 and must be considered when feeding young, growing horses.

There are generally five to eight cuttings from an alfalfa field each year when irrigated, four to five when not irrigated. The first cutting will have more weeds and grass; the second cutting is usually clean with small stems. The third cutting is good hay, and the fourth and fifth cuttings begin to have more stems and fewer leaves. As more stems are present, the quality of the hay decreases and palatability declines.

Clover and Grass Hay

Clover & Grass Hay

Clover hays are similar to alfalfa hays because they are legumes. Clover hay is usually mixed with grass hays. There are five kinds of clover hay: red, common white, crimson, alsike, and landino. White and landino clovers are usually grown for pasture. The other three contain 14 to 16 percent crude protein. Red clover causes "slobbers" in horses. Slobbers is excessive salivation that does not hurt the horse.

Learn More about Hay for Horses

• Selecting Horse Hay
• Choose the Right Hay for Your Horses
• Horse Hay Publications

Marcia Hathaway, PhD, University of Minnesota Department of Animal Science

Top 10 Nutrition Tips

1. Always supply unlimited quantities of clean, fresh water.
2. Maximize forage intake.
3. Minimize concentrate consumption.
4. The Calcium to Phosphorous ratio (Ca:P) should be between 3:1 to 1:1.
5. Supplement minerals and vitamins.
6. Balance a horse’s ration in the following order: energy, protein, minerals, vitamins.
7. Monitor your horse’s body weight and body condition score.
8. Maintain your horse’s teeth in good chewing condition.
9. Change feedstuffs gradually.
10. Feed each horse as an individual.

Supply Unlimited Quantities of Clean, Fresh Water.

Water is the most important nutrient needed by the horse. A horse should always have access to a fresh, clean supply of water maintained at a tepid temperature to encourage maximum water consumption. A 1,000-pound horse at rest in a moderate or cool environment and eating dry forage will drink anywhere from 10 to 12 gallons of water a day. The need for water will increase with an increase in ambient temperature, humidity, activity and/or a change in physiological condition. Water is typically supplied via automatic waterers, buckets or water troughs. Waterers, buckets and troughs need to be cleaned on a weekly basis, even in winter.

Maximize Forage Intake

Forages, either fresh or harvested, are the ideal source of energy. Forages, such as legumes and/or grasses are the mainstay of a horse’s diet. Most mature horses should be fed a minimum of 1 percent and ideally up to 1.5 percent to 2.5 percent of their body weight in forages each day. Eating 2.5 percent of their body weight in forage would approach the maximum voluntary feed intake for most horses and, depending on the form of the forage, would maintain some gastrointestinal tract-fill at all times. Consuming forages can provide much of the energy needs of the horse, help maintain gastrointestinal tract function and keep your horse from becoming bored. Harvested forages should be provided in a way to minimize the horse's eating directly off the ground, where it would potentially consume sand, dirt, and/or parasites. Hay should not be elevated too high, as it increases intake of molds and dusts that can lead to respiratory and potential teeth problems.

Minimize Concentrate Consumption

Frequently, when more energy than can be supplied via forages is needed, cereal grains such as oats and corn are increased at the expense of the forage component. However, there is a very real and practical limit to how much cereal grain can be fed to a horse without causing serious nutrient-related ailments. A mature horse should be fed no more than 0.3 percent to 0.4 percent of its body weight in cereal grains, per feeding. Alternatively, you may choose to substitute fats, which have been shown to be an excellent source of energy for horses, for a portion of the cereal grains. This way, it is possible to increase the energy density of the feed without incurring many of the negative side effects of too much cereal grain. Although fat is beneficial for growing, hard-working, special needs and senior horses, it is not usually necessary for the maintenance of idle horses. You want to meet the horse’s energy needs but avoid overfeeding, which would result in an unhealthy, overweight horse.

Calcium Phosphorus Ratio

The horse requires a number of different minerals in its diet. Some of the minerals, especially the major minerals, may be supplied in adequate amounts via natural feedstuffs. Common feedstuffs are not usually a reliable source of the required trace minerals, so supplementation would be recommended. Salt or sodium chloride (NaCl) should always be provided free choice as a horse will regulate its own intake. Of particular importance in managing your horse’s mineral needs, is the ratio of calcium (Ca) to phosphorus (P). Because of the interaction between calcium and phosphorus and their differing sites of absorption in the gastrointestinal tract, a minimum Ca:P ratio of 1:1 and an ideal Ca:P ratio of 2:1 is recommended.

Supplement Vitamins

Vitamins are essential nutrients needed in very small quantities and may be provided in adequate quantities via natural feedstuffs, endogenous production by the horse and microbial production in the horse’s gastrointestinal tract. Under certain conditions, it may be necessary to supplement some vitamins in the horse’s diet. For example, mature, rain-soaked and/or older hay may be deficient in vitamins. It is recommended that vitamins be supplemented to most horses.

The Horse's Ration

In general, an economical and nutritionally wise approach to feeding your horse would be to consult a reference such as the National Research Council’s (NRC) Nutrient Requirements of Horses publication (Nutrient Requirements of Horses). Revised NRC nutrient requirement for horses will be available in 2007. It provides information concerning the nutrient requirements for horses of different sizes and in different physiological conditions. It also lists the common feedstuffs and their nutritional content. Ideally, you would have your forage feedstuff analyzed for nutritional content. Using those two major pieces of information -- what your horse needs nutritionally and the nutrient content of the feedstuffs available -- you can design a ration for your horse by meeting its nutritional requirements in the following order: energy, protein, minerals and vitamins. Energy requirements are usually more easily met than protein, vitamins and minerals; hence, special effort should be made to ensure that minimum requirements of these categories are met. Alternatively, you can purchase prepared commercial feeds, such as grain mixes, to supplement selected forages or complete feeds that have been nutritionally balanced to meet your horse’s needs. Using the above information as a basic guideline, it may be necessary to modify the diet of your horse based on individual characteristics to maintain optimal body weight and condition.

Monitor Body Weight and Body Condition

You will need to know your horse’s body weight and body condition score when you are determining its nutritional requirements. Body condition scoring is based on the location and amount of fat stores underneath the horse’s skin -- along the neck, withers, over the ribs, behind the shoulder, around the tailhead and the crease on the back. The descriptive language of what to look and feel for at each of the nine different score levels can be found at:HorseQuest Learning Lesson:How to Body Condition Score Horses The ideal score for each horse will vary, depending on differences in energy expenditure, frame size, physiological condition, diet history and the owner’s personal preference. However, a body condition score of 5 is usually ideal. Visually and physically examining your horse is the best way to establish its body condition score. Assessing your horse’s body condition score on a routine basis allows for dietary adjustments to be made. How much you need to feed your horse will vary over time and is strongly influenced by changes in exercise, environmental conditions and quality of feedstuffs.

Maintain Your Horse's Teeth

Although your horse’s teeth erupt continually for 20 years, they are also continually being worn down by the grinding action associated with chewing of feedstuffs, especially forages. Because the upper and lower teeth are not in complete alignment with each other, over time, sharp points can form on the teeth. If not filed down or “floated,” the points on the teeth can make chewing painful and interfere with how well the feed is chewed. If the discomfort is severe enough, it will reduce a horse’s willingness to eat at all.

Change Feedstuffs Gradually

The horse is a hind-gut, fermenting herbivore that relies extensively on the microbes present in its gastrointestinal tract to be able to process forages. The microbes are a mix of different organisms that work together to the benefit of the horse. If the feedstuffs the microbes are utilizing are changed suddenly, there may be too little time for the microbial populations to adjust to the change. Instead, large numbers of them die, while others flourish, setting up a situation where toxins may be absorbed by the horse, resulting in digestive dysfunction. A gradual change from one feedstuff to another provides enough time for the microbial populations to adjust. For example, when changing either the type of hay or grain that is being fed, replace only about 20 percent to 25 percent of the current feed every other day, so that it takes a week or more for a complete change.

Feed Each Horse as an Individual

All horses have nutritional needs in common. They all require water, energy, protein, minerals and vitamins. How much of each of these nutrients and in what relation to each other will vary with the age, activity level, and physiological condition of the horse. The NRC requirements are the minimum amounts of nutrients for normal health, production and performance. Use them as a starting point to fine tune the needs of your individual horse.

Colostrum: The Foal's Most Important Meal

Colostrum is the first milk secreted by the mare immediately before foaling and up to 24 hours after foaling. It contains extremely high levels of antibodies, which are large protein molecules capable of transmitting immunity against disease. Colostrum is nature's way of allowing the dam to provide her foal with natural immunity. The antibodies can be absorbed through the foal's intestinal lining for approximately 18 hours following birth. However, as early as 12 hours after birth, the permeability of the foal's intestinal lining is starting to alter, decreasing in the foal's ability to absorb antibodies. In addition, the actual level of antibodies in the colostrum declines with time. Researchers have reported a 15 percent reduction in antibody levels in the mare's milk within four to eight hours after foaling.

Because of the decreased antibody absorption by the foal and decreased antibody presence in the milk, colostrum must be consumed within 15 hours after birth (Figure 1). Foals failing to receive colostrum within this time limit will be more susceptible to infectious diseases. Ideally, the foal should stand and nurse within 30 minutes to one hour after birth. Unfortunately, many horsemen panic and attempt to over assist the newborn by forcing the foal to stand and nurse immediately following birth. Unwarranted assistance at this time will result in a stressful situation and a tired foal. Foals should not be expected to hit the ground running. To the contrary, the foal should be permitted to lie, rest and be nuzzled by the mare for at least 30 minutes after foaling. Under normal conditions, a newborn foal attempts to stand under its own power within 45 minutes following birth. Foals that have not stood and nursed within two hours should be bottle fed colostrum.

When hand feeding sucklings, use a sanitized plastic bottle and nipple. Use either an infant's milk bottle, with the top of the nipple notched approximately one-eighth inch, or a lamb's feeder bottle. Thoroughly wash and rinse the mare's teat area with soap and warm water before hand milking. The washing process will disinfect the teats, limit the possibility of introducing disease to the foal and have a massaging effect on the mare's udder.

Before offering the foal its first meal, make certain it exhibits a sucking reflex. Stimulate the sucking reflex by gradually inserting your index finger into the foal's mouth and lightly rubbing the roof of the mouth. With stimulation, most foals will immediately cup their tongue and exhibit the characteristic sucking reflex. When actually feeding the foal, position the bottle and nipple so the foal is forced to suck the colostrum through the nipple. Under no circumstances pour or force-feed the colostrum. Foals that are reluctant to suck or accept bottle feedings may be fed through a tube inserted directly into their stomach. This procedure should be administered only by a qualified veterinarian.

For the first 18 hours, the foal should receive at least 1/4 pint every hour. For the remainder of the first day and through day 13, foals should receive 6 quarts daily spread over eight feedings. The colostrum should gradually be replaced with the dam's milk.

Storing Colostrum

Because the first milk is critical to the newborn foal, horsemen are encouraged to store colostrum. In areas heavily populated with breeding operations, farm managers can cooperate to form colostrum banks. Members in a colostrum bank donate colostrum from milking mares and store it for future emergency use.

Colostrum should be collected only from heavily producing mares or mares who have lost their foals. Generally, foals consume 4 to 6 ounces of colostrum per feeding. Heavily milking mares produce higher levels of colostrum than the foal is capable of consuming during these early meals. On the average, approximately 5 to 8.5 ounces of colostrum could be hand milked from the mare immediately following each nursing. The hand milking process can be continued throughout the first 15 hours after foaling.

Store the colostrum in sterile, aseptic plastic bags and freeze it immediately after collection. Colostrum can be stored for several months to a year, thus permitting its use during the next foaling season. Before feeding frozen colostrum, gradually warm it to room temperature in a warm water bath not exceeding 110 degrees F. Do not microwave colostrum, and exercise caution not to heat it too quickly. Rapid heating denatures protein and reduces immunoglobulin content. Immediately transfer the warm colostrum to a sanitized plastic baby bottle, allow it to cool and feed it as described earlier.

The immunoglobulin content of the colostrum should be analyzed within hours after birth but before hand milking. Inexpensive, easy-to-use immunoglobulin test kits are available. The kits measure immunoglobulin G (IgG) content in colostrum. Several kits also measure IgG content in serum, plasma and whole blood. These kits are used to test the immunity status of the foal 24 hours after birth. Levels of 800 milligrams per deciliter (mg/dl) are considered to provide the foal with adequate levels of passive immunity. Foals with circulating levels of IgG below 400 mg/dl are considered to have complete failure of passive immunity transfer. Levels above 400 but below 800 mg/dl are considered to have partial failure of passive immunity transfer. Immunoglobulin levels of 800 to 1,000 mg/dl are required for foals in particularly stressful situations. Foals subjected to unsanitary conditions or to many horses entering and leaving the premises will require higher immunoglobulin levels to maintain adequate protection.

Nutrient Content of Mare's Milk

In addition to supplying the foal with antibodies, colostrum also contains high levels of vitamins, proteins and energy. It also has a laxative effect on the foal. Bowel movements for the newborn foal are sometimes difficult because of the sticky nature of the first defecation, commonly called meconium. Foals that have difficulty defecating will appear colicky and exhibit labored respiration. An enema is recommended for foals who have not passed the meconium within the first five to 10 hours after birth. Consult your veterinarian before administering an enema.

Unfortunately, the nutrients contained in colostrum also decrease at a rapid rate. Researchers report that mares' milk proteins and total solids begin to decrease as early as 12 hours after foaling. Table 1 illustrates this dramatic decrease and also compares the mare's milk at foaling and two months following birth.

Research has shown a rapid decrease in total milk solids, milk proteins and milk yield from the 10th day through the fifth month of lactation. At 30 days of age, foals should be consuming at least 0.4 percent of their body weight daily as creep feed to offset the nutritional deficiencies in the mare's milk. At 2 months of age, 50 percent of the nutrients must come from creep feed. Proper management of the newborn foal, from the first meal through the first month of lactation, is essential to its future growth and development. Health and nutritional practices employed during this period are key factors in raising a healthy and productive animal.

Table 1. Composition of Mare's Milk

Source: Adapted from Feeding and Care of Horses, by Dr. Lon T. Lewis. Lea and Febiger, Penn.: Philadelphia. 1982.

Horsemen faced with raising an orphan foal have two possibilities for providing adequate nutrients. These solutions include bonding the foal to a nurse mare or providing a supplemental milk source using milk replacers. Because the foal's digestive tract is not yet fully developed and populated with cecal bacteria and protozoa, it cannot digest a solid diet. The foal must therefore consume its nutrients in liquid form. As the foal matures, bacteria will be acquired through the mare's milk and from fecal bacteria from the mare and other horses.

Nurse Mares

The easiest and most efficient method of feeding an orphan foal is to use a nurse mare. Select a nurse mare in her first or second month of lactation and give her a thorough physical examination, with special emphasis on the udder. Allow at least one or two weeks for the foster mare to acclimate to the foal. The mare may require physical restraint or tranquilizing during the initial nursing period. Two possible restraints are hobbles or a foster gate that allows the foal to nurse both sides of the mare's udder. Constructing a foster gate is not economical unless the mare is reluctant to allow the foal to nurse for prolonged periods.

Mares will use their sense of sight, smell and sound to identify their foals. Based on these habits, horsemen have two primary approaches to grafting foals onto nurse mares. One approach involves the camouflaging of the mare's senses. Several techniques can be used, including impairing the mare's sight with the use of a hood or reducing her ability to detect odors by introducing a strong-smelling substance such as mentholated petroleum jelly onto the mare's muzzle. The same substance should be placed on the foal's forehead, face, neck and tail. An opposite approach to enhancing the mare's acceptance of a foal involves coordinating her sense of smell with a similar odor on the foal. Using mare's milk, sweat or feces on the foal's body helps improve acceptance of the foal.

Equine Milk Replacers

Because many horsemen do not have access to foster mares, most orphan foals are hand raised. When hand raising foals, do the initial hand feeding with a nipple to ensure proper stimulation of the sucking reflex. Encourage the foal to suck by gently rubbing the roof of the its mouth and tongue with a moistened finger and then introducing the nipple and bottle at an angle. As the foal begins to suck, slowly remove your finger and replace it with the nipple. Nipple feed the foal for four to five days, then offer milk in a bucket.

Locate milk buckets at a level accessible to the foal but not the mare. It is best to place the buckets inside a creep feeder to allow the foal to consume milk continuously. Clean the buckets twice per day and refill them with fresh milk after each cleaning. Contrary to popular belief, supplemental milk need not be warmed.

It is preferable to feed a commercial equine milk replacer to the orphan foal. These supplements are specially formulated to meet the young foal's nutrient requirements. Avoid using cow's milk if possible because the nutrient content is not sufficient to meet these requirements. Milk replacers should contain at least 18 to 20 percent crude protein, 15 percent fat and not more than 0.5 percent crude fiber. Feeding rates are listed in Table 1.

If a commercial equine milk replacer is not available, you can use an emergency source until an acceptable milk replacer can be located. Homemade milk replacers are relatively easy to formulate. They generally consist of low-fat cow's milk (less than 2 percent butterfat content), water, lime water to reduce the incidence of diarrhea and an additive to increase both the energy content and palatability of the milk replacer. Common additives are lactose, sugar or corn syrup. Several milk replacers are listed in Table 2.

Converting to a Solid Diet

Although proper use of equine milk replacers will ensure a normal growth rate, producers should strive to convert the foal's liquid diet to a solid, high quality creep feed. This dietary change can be started at 1 to 2 weeks of age by offering 1/2 pound of a pelleted creep feed or molasses sweet feed in the creep feeder near the milk bucket. Although foals will initially only nibble at the feed, their consumption will gradually increase. As their creep feed intake increases, provide additional levels of feed so that approximately 1/2 pound is always in the creep feeder. Once each day, replace any creep feed not consumed by the foal. Gradually stop supplementation with milk replacers when the foal is adequately consuming 3/4 pound of creep feed per 100 pounds of body weight. Foals also should have unlimited access to a legume or high quality grass forage.

Table 1. Orphan Foal Feeding Program

NOTE: 1 pint equals 470 milliliters equals 16 ounces

Table 2. Milk Replacer Formulas

Source Adapted from Robert M. Miller.1983.Milk replacer formulas. The Western Horseman,48(2):38

David W. Freeman, Extension Equine Specialist

Often, it is the way rations are fed rather than their composition that leads to digestive upset in horses. Even under the best of management, several anatomical peculiarities of the horse’s digestive tract predispose horses to digestive disorders such as colic and founder. Under poor feeding management, the onset of these disorders is almost assured. The objective of feeding management is to provide a ration with balanced nutrition in a manner which maximizes nutrient utilization while lessening the occurrence of digestive disorders.

Anatomical Peculiarities of the Equine Digestive Tract

The horse’s digestive tract can be divided into two functional divisions: foregut and hindgut. The foregut of the horse is made up of the mouth, esophagus, stomach and small intestine. It functions similarly to the digestive tract of the pig in that it is made of a simple, one-compartment stomach, followed by the small intestine. The hindgut of the horse is comprised of the cecum, large colon, small colon and rectum. The cecum functions much like the rumen of a cow in that it is a relatively large, fermentative vat housing microbes which aid digestion. These microbes break down nutrient sources that would otherwise be unavailable to the horse. Each part of the digestive tract has peculiarities that relate to feeding management.

Mouth

The mouth is responsible for the initial breakdown and swallowing of feedstuffs. Chewing reduces the size of large particle feedstuffs and breaks up the less digestible, outer coverings of grains and forages. Additionally, mastication stimulates salivary glands to release saliva, which assists in lubrication of feed for swallowing.

Since proper denture conformation is necessary for mastication, inspection of the horses’s teeth by a qualified individual should be a routine management procedure. As horses age, dental conformation can be expected to deteriorate. Consequently, older horses require more frequent inspection and treatment of teeth. Signs of poor dental conformation include excessive loss of feed while eating, positioning the jaw or head sideways while chewing and evidence of general loss of condition and thriftiness.

Esophagus

The diameter and tone of the musculature of the esophagus make it difficult for the horse to expel gas through belching or vomiting. These are predisposing features to gastric rupture, gastric distention and colic.

Stomach

Compared to most livestock, the size of the horse’s stomach is small, about 10 percent of the volume of the total digestive tract. The small size makes the rate of flow of feed material in the digestive tract through the stomach relatively fast. Gastric emptying is dependent upon volume, so large meals can be expected to pass more quickly than feed eaten continuously at low volumes. Studies have shown the majority of feed material in the digestive tract passes to the small intestine within 12 hours following a meal.

Small Intestine

The small intestine is the main site of digestion and absorption of protein, energy, vitamins and minerals. Similar to the stomach, intake level of the feed influences rate of flow of ingested matter through the small intestine. Large amounts fed in meal feedings increase rate of flow to the large intestine.

Cecum and Colon

Ingested matter not previously digested or absorbed in the small intestine flows to the cecum and colon, which make up about 50 percent of the volume of the digestive tract. The cecum and colon house bacterial, protozoal and fungal populations which function in microbial digestion of feed material in the digestive tract. Many different products of microbial digestion are absorbed by the horse.

Passage of ingested matter through the large and small colon is relatively slow. Rates of flow through the colon may take up to several days following the time feed was eaten. The diameter of different segments of the large colon varies abruptly. Additionally, the arrangement includes several flexures where the colon turns back onto itself. Anatomical arrangements such as these predispose the horse to digestive upset when nutrient flow is abnormal.

Nutrient Intake and Digestion

Water

The daily minimal requirement for water has been estimated to vary from 5 to 20 gallons. Requirements depend on factors such as environmental temperature, workload, production state and intake. Voluntary water intake can be expected to increase as the amount of ration eaten increases. Also, rations low in digestibility increase water intake. Furthermore, horses can be expected to drink more frequently when exposed to hot environmental temperatures. Horses exercising in temperate environments may have increases of 300 to 400 percent in water requirements for replacement of water that is loss in expired air and sweat. Since restriction of water intake may cause digestive upset, recommendations generally are for free choice access to clean, palatable water.

Energy

Energy is the fuel for chemical reactions which run the various systems of the body. Energy-containing compounds are part of grains, forages and many supplements. Energy is supplied in the form of starch, fiber and fat.

Starch is found mainly in grains, and as much as 55 to 85 percent of starch is absorbed in the small intestine. Starch bypassing to the hindgut is digested by microbes and absorbed as volatile fatty acids. Large amounts of starch presented to the hindgut predispose horses to colic because of gaseous products of microbial digestion and abnormal changes in gut pH and fluid balance. The amount of starch bypassing to the hindgut depends on intake level, rate of flow through the digestive tract and amount of mechanical disruption of the hard seed coats of grains. Results from nutritional studies suggest that approximately two grams starch per pound of a horse’s body weight increases starch bypass to the point of causing digestive upset. Considering starch levels in typically formulated grain mixes, recommendations are to split daily grain needs to two or more daily feedings when grain levels are greater than 0.5 percent of body weight per day (example:5 to 6 pounds of grain for a 1,000-pound horse).

Hay and pasture forage are the most common sources of high-fiber feeds fed to horses. Fiber digestion is dependent on the efficiency of digestion from microbial fermentation in the cecum and colon. Compared to cattle, horses are less efficient in digesting most sources of fiber, presumably because of faster rates of passage of ingested matter. Also, fiber digestion is dependent on the maturity and type of forage. Mature, stemmy forages are inefficiently digested, whereas digestion of immature, leafy, small-stemmed sources of fiber are similar in horses and cattle. Processing hays in cubes, pellets or chop has little effect on digestibility but may be helpful for feeding to older horses with poor teeth condition.

Fat is a component of most feedstuffs. Nonsupplemented grain mixes typically have minimums of 2 to 3 percent fat. Adding additional levels of fat in formulations for grain mixes has become a common practice. This supplementation increases the energy concentration of grain mixes while decreasing the amount of starch. Therefore, fat-added feeds have advantages of being more concentrated in energy and safer because of containing less starch as a total part of the energy-containing compounds.

Protein

Proteins supply amino acids. Amino acids are used in a variety of body processes, largely for developing and maintaining lean body tissue. Amino acids are absorbed intact in the small intestine, while protein in the hindgut is absorbed primarily as ammonia. Some of the essential amino acids must be absorbed intact because the horse’s body cannot synthesize them. Thus, increasing the efficiency of protein digestion in the foregut is desirable. Total tract and prececal digestibility vary with protein source and protein concentration in the diet. Total tract protein digestibility of feeds typically ranges from 40 to 70 percent. As much as 75 percent of protein in soybean meal is digested in the foregut, whereas estimates for prececal forage digestibility range from near zero to 20 percent. Slowing the passage of protein by splitting daily needs into two or three feedings per day will increase amino acid absorption in growing horses.

Minerals and Vitamins

Mineral and vitamin imbalances, deficiencies and toxicity can cause a multitude of health disorders in the horse. In many cases, recommendations are based on limited research or requirements and have not been established because of absence of research.

Calcium and phosphorus are the two minerals which have received the most research attention. Horses require more calcium than phosphorus and are susceptible to skeletal system disorders when fed less calcium than phosphorus. Additional minerals receiving considerable attention in recent research include copper and zinc, also because of implications related to skeletal growth disorders.

Research information on vitamin requirements is largely absent in equine nutrition. Fresh forage is a major source of vitamins, and most needs are considered met when horses have access to quality hay or pasture. Vitamin A is the most commonly supplemented vitamin in rations, partially because of the large needs for production and growth. Vitamin D is also routinely added, especially to horses who do not receive fresh forage. The needs for vitamin D are less than for vitamin A, and recommended upper levels of safe intake are much lower.

Requirements of the other fat-soluble vitamins, E and K, are less clear, and clinical deficiencies and toxicity are not as commonly observed. Sources of vitamin E are routinely added to equine diets to guard against deficiencies which cause myodegeneration, or breakdown of muscle. Vitamin K requirements are presumed to be met by synthesis of vitamin K sources by microbes in the cecum and colon. Requirements for B vitamins are largely unknown. B vitamins are assimilated by microbes in the horse’s cecum and colon, and these sources are assumed to meet the needs of most horses. However, B vitamin supplements are routinely added to diets of exercising horses because of the role of B vitamins as catalysts for energetic pathways.

Feeding Management Implications

Water

As discussed previously, water intake is important for maintenance of normal body processes. Restrictions in water, such as that caused by voluntary reductions in response to abrupt decreases in environmental temperature or changes in water source, may cause an increase in the incidence of colic. Water intake should be monitored because of numerous health problems associated with dehydration. Monitoring water intake requires frequent inspection of water sources, including the function of automatic waterers. In general, horses should be allowed free access to fresh, palatable water. Some horses may drink so much as to cause digestive upset if given free access immediately prior to performing and recovering from intense exercise, and it is recommended that water should be provided in smaller amounts at frequent intervals during these times. Regardless, dehydration can be a serious problem in exercising horses. Therefore, it is important that water is offered frequently and that intake is monitored.

The Need for Long-Stem Forage

Rations for horses should be forage based. Generally, horses should have access to pastures, hays or coarsely processed forage at minimal levels of 0.75 percent of body weight per day. Among other benefits, incorporating long-stem forage into rations increases particle size of ingested matter, thus slowing rate of passage. It also increases dry matter intake, thus stimulating water intake. Additionally, incorporating long-stem forage reduces the frequency of behavioral problems such as tail chewing, wood chewing and feeding on excrement. Grain mixes should be formulated to balance and add to the value of forages. High quality forages are more concentrated in nutrients and more efficiently digested; thus, lower levels of grain supplementation are necessary. Feeding forages containing weeds, insects, large amounts of indigestible fiber or foreign material will predispose the horse to digestive upset.

Meeting Requirements with Balanced Rations

Nutrient balances are important for all diets. However, horses in production, growth or performing high levels of athletic competition or work are most likely to develop observable disorders from ingesting an imbalanced ration. A feeding management plan requires knowledge of requirements, an ability to formulate rations and knowledge of utilization of different feedstuffs.

Growing horses, exercising horses, gestating and lactating mares and stallions during breeding programs require more nutrients than horses at maintenance. Feeding management plans should consider these differences, and farm facilities should separate horses into different production classes. The feeding management plan should also consider the number of different classes of horses, the ability to correctly add supplements on-farm, the ability to feed different numbers, as well as types of rations, feeding costs and the availability of different feedstuffs.

Meeting requirements also requires knowledge of nutrient content of grains, forages and supplements. Rations have successfully incorporated many different combinations of fresh forage, hays, grains and supplements. However, feedstuffs contain different levels of energy, protein, minerals and vitamins. Knowing the expected nutrient profiles of selected feedstuffs will direct supplementation to meet needs without causing deleterious effects on performance or health.

Estimates of the nutrient content of feedstuffs can be obtained from feed tags on grain mixes, feedstuff tables in animal nutrition texts, professional nutritionists or chemical analyses. Because of the variability in forages, farms using significant amounts of hay from a single source should have hay sources routinely tested for protein, fiber and minerals.

Maintaining a Nutrient Balance in Rations

Feedstuffs contain differing levels of nutrients. Grains are relatively higher in energy than forages, some byproduct feeds contain high levels of protein, and mineral and vitamin levels can be expected to vary greatly between different feed sources. Because of these differences, changing sources or amounts of feedstuffs will alter the nutrient balance in rations. Commercially formulated grain mixes are routinely supplemented with nutrients, so the different ratios of grain and hay and different hays that horses are fed will not adversely alter the nutrient profile of the total ration.

Some feeding managers are equipped to properly supplement rations by on-farm addition of ration ingredients, whereas others routinely make uninformed decisions to add many different types of nutrients to the base rations. The unknowledgeable addition of ingredients can easily cause numerous irreversible health problems in all classes of horses. Two problems frequently observed with improper ration adjustments are supplementation without knowledge of need or level of intake before supplementation, and supplementing for one ingredient without recognizing the additional amount of other ingredients a supplement may contain.

Additionally, horses should not be expected to self-regulate their need for most nutrients. This is evidenced by horses overconsuming energy to the point of digestive upset. In addition, horses do not regulate most of their mineral needs under free-choice management. Additional needs for minerals should be met as part of a formulated ration at regulated intakes. The exception to this rule is the free choice offering of salt, or sodium chloride. It is generally recommended that all classes of horses be provided salt, either plain or trace-mineralized, in block form with the constraint that free-choice, palatable water is available at all times.

Feeding to Desired Body Condition

Horses in a positive energy balance will store energy as fat, and body fat is reduced when the ration does not provide sufficient nutrients to maintain energy balance. Accurately assessing the fat cover allows for visual appraisal of the energy status of a horse. In general, most horses should be fed a balanced ration at levels which produce a moderate to fleshy body condition, thus avoiding an extremely thin or obese condition. Because horses in similar production and weight classes will vary in their nutrient needs, routine assessment of body condition of each horse is necessary. While horses in similar production and weight classes are commonly grouped together, those individuals with abnormally high or low body condition may need to be separated further to meet individual needs.

Assessing Energy Sources, Levels and Utilization in Feeds

Voluntary intake in horses appears to be influenced by a number of factors: weather, palatability of feed, interaction with other horses, and energy intake, among others. Regardless, if allowed free access, most horses will consume enough grain to cause digestive upset. As discussed previously, the most common problem with overeating is the consumption of too much starch in a single feeding. Grains vary in the amount of starch. For example, corn has more starch per pound than oats. Also, there may be differences in foregut digestibility of starch between different grains. Depending on intake, more starch in oats may be digested prececally than corn.

The Value of Processing Feeds

Processing increases digestibility of hard seed-coat grains and assists in intake of ingredients with different particle sizes in a mix. Feeding finely processed rations such as ground mixes is not recommended because it may decrease palatability, increase dust, increase incidence of gastric upset and increase the rate of flow of nutrients through the digestive tract.

Pelleting, micronizing, flaking, rolling, cracking, wafering and extruding are examples of processing methods that are acceptable. Several different pellet sizes have been successfully fed to horses, most ranging from 0.2 to 0.75 inches in diameter. Often, forages are recommended to be fed loose so behavioral abnormalities resulting from boredom are reduced. However, cubed (1 1/4 inch in diameter) hay can be fed as the sole source of forage with no reported incidence of behavior abnormalities.

Processing can cause several differences in rate of intake and utilization of nutrients. Completely pelleted rations are consumed faster than textured grains. Extruded feeds are consumed more slowly than pelleted or textured grain mixes. Texture and hardness of grains will determine the value of processing. Small seed grains with hard seed coats, such as milo and wheat, should be processed to increase utilization of nutrients. The benefit of processing softer seed-coated grains, such as oats, is much less. Also, the value of processing grains can differ between horses. Horses with poor denture conformation, such as older horses, may benefit more from processed feeds than others. Also, the value of processing is increased when feeding large quantities of grain to horses with limited capacity, such as rations fed growing horses to obtain maximum gain.

Total rations may be mixed, ground, and processed by pelleting or extrusion to make a complete feed. Complete feeds have several advantages, most related to ease and convenience of feeding. However, it is most commonly recommended to provide at least 0.75 pounds per 100 pounds of body weight in long-stem forage to supplement these complete feeds to guard against tail chewing, coprophagy and gastrointestinal problems.

Feeding by Weight of Ration Instead of Volume

Feeding by weight will decrease the chance of overfeeding due to differences in weight per volume of different feeds and different processing methods. For example, corn weighs more per volume than oats, and pelleted feeds weigh more per volume than textured feeds. Consequently, it is recommended to weigh feed periodically to insure accurate monitoring of intake. This is especially important when changing feed sources. One of the most common causes of digestive upset is overfeeding energy in a single feeding because differences in weight of grain mixes were not taken into account.

Feeding Frequency

In many ways, the horse’s digestive physiology is best suited for a continuous, low-level supply of feed. However, for management, housing and production needs, most horses are meal-fed. Meal-feeding large amounts of starch increases starch bypass into the cecum and colon. As discussed previously, large amounts of starch presented to the hindgut increases the frequency of digestive upset. Therefore, it is recommended to split grain into two daily feedings when the daily amount of grain exceeds 0.5 percent body weight (5 pounds grain per 1,000-pound horse). Those feeding grain to horses at levels of or above 1 percent of body weight per day should consider splitting amounts into three portions per day. Meal feedings should be separated as much as possible -- that is,10 to 12 hours between a.m. and p.m. feedings for two daily meals.

Reducing Rate of Intake

Reducing rate of feed intake may be desirable if horses bolt their feed, resulting in choking or digestive upset, or if reducing rate of intake decreases competition in group-fed horses. When horses are fed in individual feeders, methods used to slow feed intake in abnormally fast eating horses have included spreading grain out in shallow troughs, placing several large stones in the feed trough, requiring the horse to eat around them or using spaced bars or feeding rings to limit access to the feed trough. As discussed previously, processing of the ration also influences the rate of intake. While the fiber content or size of pellet does not seem to affect rate of intake, increasing pellet density, or hardness, has been shown to slow intake of a pelleted grain mix.

Group versus Individual Feeding

In groups, horses tend to do what other horses do. One horse eating encourages others to eat. Similarly, appetite can be stimulated in individually housed horses by allowing a horse to observe other horses eating.

Competition among horses in group-fed situations may allow some horses to consume more feed than needed while others are not allowed access to adequate amounts. To reduce competition among horses, group-housed horses should be fed grain in individual feeders that are spread out over a large area, that is, 50 feet between feeders. Additionally, slowing the rate of intake of grain by reducing the desire to eat may reduce competition. Supplementing pastures with free choice hay in times of limited forage production may slow rate of intake of grain because horses may not be as hungry at meal time.

However, even under the best management, horses low on the herd pecking order or stressed because of conditions such as old age or lameness will need to be housed separately to reduce competition.

The Need to Make Gradual Changes in Rations

Grains and hay differ in nutrient content. Changes in the intake level and the physical form of rations should be done gradually over several days to weeks. This practice allows the digestive tract time to adapt to different levels and physical forms of nutrients and is especially important when feeding energy-dense rations. As such, grain amounts should be increased incrementally when changes in management require an immediate need for more energy. For example, increase grain one-half pound every two to three days until energy balance is met. For similar reasons, introduce horses to pastures with large amounts of lush forages by limiting access for several days.

Incorporating the Feeding Management Plan with Total Farm Management

The source, ingredient mix and number of rations will depend on numerous management practices that interrelate with the feeding program. The need to transport to events, timing of exercise schedules, labor constraints and costs are significant management factors which affect feeding management. Deworming, vaccination schedules, ectoparasite control and general hygiene are examples of health practices that relate the nutritional plans and the well-being of the horse.

Effective management also involves treating each horse as an individual. As such, effective management requires an accurate, quantitative record-keeping system that allows for individual assessment of each horse.