Until the 1980s, many riders tended to extrapolate to the horse the knowledge acquired from other species and equestrians considered that the horse’s organism did not function like that of other animals, basing themselves on an ancestral tradition to feed the animal. A better knowledge of feeds, associated with scientific research conducted throughout the world concerning the nutritional needs of the horse in each physiological situation, has allowed the evolution of standards that now ensure, when followed, a rational and balanced diet for the horse. What food should I choose for my horse? Are alfalfa, hay, and pellets good for horses?
Just like humans, horses constantly need an energetic fuel – food – and an oxidizer – oxygen – to produce heat and energy.
The body temperature is thus kept constant, and the organism can build itself up and live without ever ceasing to renew itself.
To feed your horse properly, it is important to understand the essential role of nutrition, which is made up of “all the exchange phenomena between an organism and its environment, allowing the assimilation by the living being of substances that were foreign to it and the production of its vital energy.” A nutrient is a simple element that must be included in the composition of the horse’s feed ration in proportions that allow it to be maintained in good health according to its physiological state.
The horse and water: the most vital of all nutrients
Two-thirds of a horse’s body is made up of water and all its tissues are bathed in it; a muscle, for example, contains 30% of its weight! If a horse’s body can lose all its fat and half of its protein and still stay alive, the loss of only 8% of the water in its body composition will result in death. The functions of water are so numerous and so important that it remains the most essential nutrient for the horse as for any living being. In horses, drinking water requirements, in addition to the water contained in the feed, can vary from 20 to 75 liters per day, depending on the size, the climate, the intensity of the work (significant water loss through sweat) and the nature of the ration. For example, in the case of diets based on young grass, wet pulp, beet, carrots, lamb’s lettuce or sprays, the amount of water supplied will be less.
The horse and protein
While they can be a source of energy, proteins are primarily used to build, allowing the synthesis of bones, muscles, and all other tissues. A protein is a molecule made up of a chain of amino acids, a sort of train made up of wagons (non-essential amino acids that the body can synthesize) and locomotives (essential amino acids that the animal must find in its food).
The total nitrogenous matter (TNM) or crude protein matter (CPM) represents the proteins measured in the ration (found on the feed labels). Their digestible fraction – more interesting from a nutritional point of view – is called HDNM (Horse Digestible Nitrogenous Material). In terms of quality, they are likely to cover the body’s needs in essential amino acids. During maintenance, the horse’s protein requirement is close to 60 gr of MADC per 100 kg of body weight per day. This requirement increases during growth, gestation, and lactation. It remains moderate for sporting activities.
The horse and fats
The key role of dietary fats is to provide energy. The horse digests them very well and makes remarkable use of them during endurance work. However, depending on their origin, fats have very different fatty acid compositions and therefore do not have the same nutritional value. Some are used to supply energy while others are precursors of hormones and part of the cellular structure.
The latter are called “essential” fatty acids because the horse cannot synthesize them and must therefore find them in its diet. There are two families of essential fatty acids (EFA):
- the “omega 6” series, which is found more naturally in vegetable oils (corn oil, sunflower oil, grape seed oil);
- the “omega 3” series, which is well supplied by young grass, flaxseed, borage and, to a certain extent, soybean oil.
The horse and lipids
The quantitative contribution of lipids as an energy fuel makes it possible to take advantage of their very high concentration (2.25 times more than carbohydrates) which corresponds to 3 to 3.5 F.U. (Horse Feed Unit) per kilogram of fat. They are therefore particularly useful whenever the animal is in a situation of intense energy loss (gestation, lactation, growth, endurance work).
The horse and carbohydrates
Carbohydrates: concentrated energy via the cereals present in processed feeds
The basic elements of carbohydrates are what are called oses, simple sugars; the most common of these oses is glucose, the basic constituent of starch and cellulose. Other carbohydrates, such as pectins or gums, are more complex molecules. Some of these carbohydrates are digestible and assimilable by the horse’s body (this is the case of starch, sugars and certain fibers made digestible by intestinal fermentation); the indigestible carbohydrate (so-called insoluble fibers) constitutes the ballast that stimulates and regulates intestinal transit.
Among the important digestible carbohydrates, lactose is of particular importance in foals, as mare’s milk is rich in it. Starches are made up of a complex of glucose polymers that are branched, depending on their botanical origin, and are bound together like a ball called a starch granule. Present in large proportions in cereals (corn, wheat, barley, oats) but also in all plants, they constitute a privileged source of energy for the horse provided that the daily intake is measured. However, be careful with certain products, such as horse treats and candies.
The horse and dietary fiber
Dietary fibers are defined as all carbohydrate compounds that can be digested enzymatically. They are made up of different carbohydrates constituting the membranes of plant cells (pectins, hemicelluloses, true cellulose, lignin), and each of these groups is likely to behave differently in the digestive tract.
We distinguish:
- soluble fibers, with pectic substances (beet pulp, citrus pulp, apple pomace…), gums and mucilage (flaxseed), and hemicelluloses (grains and issues, seeds, and cakes). These soluble fibers have gelling properties in the intestine, which influences satiety, the speed of digestion and helps to better regulate glycemia, lipemia and cholesterol levels. They are likely to ferment in the cecum, generate flatulence, and wet droppings when their intake is not balanced;
- insoluble fibers, made up of true cellulose, which lignifies with the age of the plant, thus becoming less and less digestible (like fodder harvested too late, straw, or grape seed cake). Insoluble fibers are nevertheless important because they contribute to the mental hygiene of the animal: by increasing the time of consumption and chewing, they become a factor of occupation and tranquilization allowing to prevent certain tics.
Too much fiber devalues the whole ration and can lead to stasis colic (blockages in the large intestine). Conversely, deficiencies can lead to an exacerbation of intestinal fermentation, which can cause diarrhea, fur, colic, and boredom.
The horse and minerals
Minerals represent only a small proportion of a horse’s weight, but their role is essential, and their dietary intake must be closely monitored.
Each of them is likely to interfere with others at the digestive or metabolic level. It is therefore necessary not only to ensure the intake of each of them, but also to avoid any imbalance that may be just as harmful to the body as a simple deficiency. In nutrition, these minerals are artificially divided into two groups:
- macroelements (whose need is quantified for each in grams for a standard horse), represented by calcium, phosphorus, magnesium, sodium, potassium, and chlorine;
- trace elements (whose need is expressed in milligrams per day, or even less), including iron, copper, manganese, zinc, iodine, selenium, fluorine, cobalt, molybdenum…
Quantitatively, calcium and phosphorus are the major mineral elements, fundamental constituents of the skeleton; they also have other important metabolic functions, such as the role of phosphorus in all energy transfers within the cell. The skeleton represents a very important buffer reserve from which the body draws in case of deficit, which explains the appearance of bone diseases when the phosphocalcic intake of the ration is unbalanced. Magnesium is also involved in bone metabolism, but it is, along with potassium, an element of the intracellular fluid that is fundamental to a large number of reactions.
Trace elements are essential to the constitution of red blood cells, to the transport of oxygen, to the pigmentation of the skin and to its integrity, to the functioning of enzymatic systems and to hormonal synthesis. Each one of them fulfills one or more roles for such or such function of the body.
Their intake must be reasoned and controlled by referring to the manufacturers’ prescriptions on the labels.
The horse and vitamins
Among all the nutrients essential to life, everyone knows the word “vitamin”, which in fact covers a wide range of substances. When one of them is missing, either totally or partially, clinical symptoms of deficiency appear, which can lead to serious illnesses overall.
They are found in food and can be, depending on the case, liposoluble (soluble in fat: vitamins A, D, E, K) or hydrosoluble (soluble in water: vitamins C and B complex).
In horses, hypervitaminoses are occasional, especially A and D, while deficiencies are rare. On the other hand, vitamin E is very well tolerated, even at high doses, for which it may have curative and preventive properties for the cell membrane.
The B vitamins are synthesized in the colon by the intestinal flora. Despite rare C deficiencies, it is important to note the interest of vitamin B8 (H) or biotin supplements for the quality of horny productions (hair, mane, hoof wall).
Knowing the nutritional needs of your horse
The knowledge of the nutrients essential to the life of the horse makes it possible to specify its nutritional needs both quantitatively and qualitatively. They correspond, at the base, to the strict maintenance needs of the animal (linked to its weight) to which will be added the needs known as of production (gestation, milk production, growth, or muscular work).
To express a need accurately and, consequently, to ensure precise coverage, it is advisable to refer to systems of additive units that ensure the homogeneity of the mode of expression of the nutritional need according to the animal species. The water requirement is expressed in a simple way in liters of water to be supplied each day to the animal, including the water contained in the feed.
In horses, the notion of dry matter “requirement” must also be considered: the level of voluntary consumption, commonly referred to as appetite, defines the overall volume of the ration and therefore conditions the nutrient concentration necessary to cover the requirements. This “appetite” is expressed in kilograms of dry matter (feed minus water content) per 100 kilograms of body weight, to show the predominant influence of the size of the horse. This average level of voluntary consumption is around 2 kg DM/100 kg body weight with the usual mixed rations and can rise to 3 kg in certain cases (lactation, breeding period). Phytotherapy can also be used to supplement the horse’s diet.
For more information: adapting your horse’s ration
