Nutrient requirements of the horse

The horse is a non-ruminant herbivore, designed to live in herds, roaming freely over open plains, typically eating for 16-20 hours a day, surviving on a diet of grass, shrubs and herbs which are high in fibre and low in starch. Man’s domestication of the horse has in general restricted feeding time and introduced uncharacteristic feeds such as starchy cereals, protein concentrates and dried forages.

The modern horse requires a higher energy diet than that of its ancestors to meet the energy and performance requirements placed on it and forage is not always able to satisfy the nutrients or energy needed, therefore concentrates must be fed to allow the horse to perform efficiently. However, it is vital to ensure that these feeds meet the nutrient requirements of the horse without causing digestive and metabolic upset by providing sufficient fibre in the diet for correct and efficient digestion and satisfying behavioural needs.

In order to keep our horses healthy and to enable them to perform well, a balance of over 40 nutrients are required, which fall into 6 categories:

1. Water – is essential for digestion, aiding the movement of digesta through the gut. Water is essential for growth and lactation, temperature regulation and the excretion of toxins (in the form of urine). It also maintains the integrity of cells and tissues and is present in every bodily fluid. Clean water must be available at all times.
2. Carbohydrates – come in two main forms: simple carbohydrates (sugars and starches) and complex carbohydrates (fibre or cellulose). Carbohydrates are a major source of energy and provide the required energy for all cell process and basic functions (ie breathing). They also provide energy for muscle contraction, which is why higher levels of carbohydrate are required by performance horses. However, excess carbohydrate can lead to obesity, whereas a deficiency in carbohydrate can lead to the horse breaking down body reserves to supply necessary energy, ultimately leading to a loss of condition.
3. Protein – is required for healthy tissue, cell renewal, milk production and is a good source of energy. Protein is made up of two types of amino acids: non- essential and essential. Non-essential amino acids can be synthesised by the horse itself, so need not be present in the diet as the horse can make them as required. However essential amino acids must be provided in the diet as they cannot be synthesised by the horse.
4. Fats and oils (lipids) – are sources of essential fatty acids and are a concentrated source of energy and a carrier for fat-soluble vitamins. They are essential for working, performance, lactation and growth, providing slow release energy and adding body condition.
5. Minerals – macrominerals and microminerals are an essential part of a balanced ration and are vital for optimal health and performance. They form the constituents of bones and teeth, are present throughout tissues and fluids, and have a vital role in biochemical reactions.
6. Vitamins – there are two types; fat-soluble vitamins (A, D, E and K) which can be stored in the body and water-soluble vitamins (C and B group) which cannot be stored in the body and need to be renewed daily. Vitamins are vital for the health and welfare of the horse and are required for many metabolic processes and chemical reactions that occur in the body.

Energy is mainly obtained from carbohydrates, fats and oils and excess protein. It is required for nearly all life processes and is the most important factor in the diet. Energy is the horses fuel and without it, the horse would not function.