A Guide for the Basic Principles of Horse Nutrition

With so many feeds, supplements, and hay choices available, it can be difficult to be certain about what is essential for your horse's health and nutrition. This guide helps clarify the nutritional requirements of your horse, outlines general feeding principles, and assists in evaluating whether your horse's dietary needs are being met. Learn about making informed decisions to create a good, solid nutritional program for your horse.

Overview of the Gastrointestinal Tract

The horses digestive system is large, complex and very sensitive to change. The primary function of the digestive system is to transport food from the mouth to the anus and to break down food into particles that can be absorbed. In horses, the digestive system is divided into two main parts: the foregut and the hindgut. The foregut includes the oral cavity, pharynx, esophagus, stomach, and small intestine, where enzymes and acids work to break down feed components such as proteins, fats, and hydrolyzable carbohydrates. Horses have a distinctive stomach with a capacity of only 2 to 4 gallons for an average-sized 1000 lbs horse. This stomach produces hydrochloric acid and pepsin to start breaking down food. Unlike some animals, horses lack a gall bladder to regulate acid production, leading to constant acid secretion. As a result, horses have evolved as grazers, spending approximately 16 hours a day grazing on pasture grasses. This grazing behavior creates a protective layer over the acid to prevent it from splashing up and causing ulcers in the non-glandular parts of the stomach.

Materials that remain undigested then proceed to the hindgut, which comprises the cecum, small and large colon, and the rectum. Horses are classified as hindgut fermenters, with a variety of microbes breaking down this material. These microorganisms primarily utilize the fiber from the horse's diet to generate approximately 75% of the horse's daily caloric requirements. Forage typically contains more fiber than other feeds, making it crucial for maintaining the health of these microbes. Therefore, providing a forage-based diet is essential for the horse. Imbalances or feed that disturb these microbes may result in hindgut acidosis, ulcers, displacements, or gas accumulations, all of which can lead to colic.

Basic Nutrients

Horses need six essential nutrient groups to thrive and maintain optimal health: carbohydrates, proteins, fats, vitamins, minerals, and water.

Water

Water is a crucial nutrient for horses for many reasons, such as aiding digestion, regulating body temperature, supporting biochemical reactions, waste elimination, and milk production in broodmares. The water requirements of a horse can vary based on different factors. A healthy horse typically consumes 15-25 (or more) litres of water daily, depending on environmental conditions and activity level. It is essential to provide clean water daily and ensure continuous access for the horse. It is worth noting that snow is not a suitable water source for horses as they cannot consume enough snow and it requires significant energy to warm it to body temperature.

Carbohydrates

The horse's diet will primarily consist of carbohydrates. These can be categorized into two groups: structural (fiber) and non-structural (sugars and starches)