During the last three decades, there has been an increased awareness of equine nutrition and its importance to the health of the horse. In every stage of a horse’s life, nutrition is the foundation for good equine health and longevity. The dietary needs of a horse change as it goes through each life stage. The great number of varieties of commercial feeds on the market attest to the recognition different life stages require different diets. For optimum health, horses must be provided with an adequate supply of energy, protein, vitamins, and minerals and have access to fresh, clean water.
It goes without saying that adequate fresh water intake is essential for every horse. Storage tanks, troughs, or pails should be placed so the horse can reach in comfortably. Many horses are reluctant to put their head in a trough or pail below eye level, so the water level should be kept high. If water levels get too low, many horses will refuse to drink. The optimal temperature for drinking water is 68°–78°F (20°–26°C). Horses will often reduce water intake if the water temperature is too cold or too warm. If daytime temperatures exceed 100°F (38°C), water in exposed pipes or hoses can be dangerously hot and should not be used for drinking or bathing.
The nutrient energy requirement of the horse is determined by its level of activity, the energy content of the diet, and the capacity of the animal’s digestive system. The size and weight of the newborn foal is influenced by the nutrition of the pregnant mare. Horses specifically fed for rapid body and skeletal growth may develop bone abnormalities or be more prone to lameness conditions. A balanced diet should be fed according to the desired rate of gain within the sound parameters of good health. The best measure of growth in a young horse is weight, and the best description of size of a horse is a combination of height and weight. A high correlation between the measure of the heart girth and body weight in the horse has been reported. In young, growing horses, monthly measurements are helpful to monitor growth changes.