Of all the components of your horse’s diet, protein is probably the most misunderstood. Long assumed to be an energy source, protein actually has quite a different function–it provides amino acids. Amino acids are the building blocks of bones, muscles, and virtually all of the body’s soft tissues, for growth and repair.

This makes protein an essential part of the diet, but it does not necessarily mean that more is better. Growing horses, which are "building" new tissues as they mature, and horses being used for breeding have a higher protein requirement than do mature horses, whether working or idle. Mature horses have surprisingly low protein needs. And while protein can serve as an energy source, it’s a poor one in comparison to carbohydrates and fats, which the horse can metabolize far more efficiently. This information is slowly changing the way we formulate equine diets, as well as the way we think about which protein are appropriate for our horses.

Inside A Protein Molecule

Proteins are "chains" made up of various combinations of the 22 different amino acids that exist in nature. Amino acids are relatively simple organic compounds, consisting of a basic amino group (described in chemical shorthand as COOH) and an acidic carboxyl group. Carbohydrates and fats also contain carbon atoms with hydrogen and oxygen atoms attached, but amino acids alone contain nitrogen and sometimes sulfur. The position and number of the amino acids in a single protein make up its "amino acid profile" (more on this later).

When a horse ingests protein, the chain of amino acids is broken u