What is protein?

Protein is the second-most major component of body tissues, the first being water. All proteins are made from amino acids. Amino acids are the “letters” that make up the “words” of protein. There are 22 amino acids that combine to make proteins of different sizes, shapes, and functions. Examples of protein include myosin (which facilitates muscle contraction), hemoglobin (which carries oxygen in the blood) and immunoglobulins (antibodies that neutralize pathogens).

Why is protein important in the diet?

Some amino acids are made in the body. Others, called essential amino acids (including lysine, methionine, and threonine), must be consumed via diet. Without essential amino acids, some proteins cannot be made, depriving the body of important resources. A “complete” protein contains all essential amino acids.

How much dietary protein is needed?

Protein requirements depend on a horse’s age, life stage, available feedstuffs, and workload. Some proteins, such as those in cereal grains, such as oats and barley, have highly digestible protein, whereas the protein digestibility in mature forage is lower. Most mature horses require about 10% of the total diet as protein. Growing horses and pregnant or lactating mares have much higher protein requirements. Convalescing horses might also benefit from extra dietary protein.

Take-Home Message

Protein is important for every aspect of a horse’s physiological function, but protein requirements depend on several factors. Feeding good quality forage and, when necessary, supplementary grain concentrates is usually sufficient to provide horses with a strong nutritional base for healthy living.