Proteins are essential to horses; they constitute approximately 80% of their total body structure, when water and fat are not considered. The primary role of protein is to provide the horse with the amino acids needed for growth and tissue repair. Amino acids serve as building materials for bones, muscles and soft tissues. What should be of most interest in horse owner’s is the amino acid profile of the protein.

AMINO ACIDS AND PROTEIN QUALITY

A protein molecule consists of a combination of 22 amino acids. When the animal ingests the protein, the enzymes and acids in its digestive system break down the chain of amino acids and each one is absorbed through the lining of the small intestine and into the blood, via the liver. The amino acids are then distributed in areas where they are needed.

Of the 22 amino acids that make up the protein, 10 of them cannot be produced by the horse’s metabolism. They are called essential amino acids, and they need to come from forages or commercial feeds and supplements.

Good sources of protein should provide a proper quantity of essential amino acids, including lysine, methionine and threonine as they cannot be produced by the horse. Lysine, the first limiting essential amino acid, is very important; if the horse does not have enough of this amino acid in its diet, it will not be able to absorb and effectively use the other amino acids.
The following protein sources have a good amino acid profile for horses: dehydrated yeast, soybean meal, canola meal, whole milk powder. The protein content in horse feedstuffs is mostly expressed in crude protein (CP); this measure unit does not specify the source of the protein nor the quality of the amino acid profile.

In fact, if the source of the protein used for a feed is deficient in essential amino acids, your horse’s needs may not be met. The protein quality will influence the general muscular and body condition of a horse, and its athletic performance. It will also influence the growth of a young horse and the reproductive success of a breeding mare or stallion. Excess of protein in the foal’s ration has long been blamed for orthopaedic developmental diseases, but studies mostly invalidate this assertion. Indeed, the most recent research rather incriminates the excess of calories in the foal’s ration as being the issue, event more so if the mineral level of the ration is too low or poorly balanced.

It is important to choose a feed that will fit the needs of your horse. For example, for a weanling, choosing a reputable feed formulated for foals is the best option. If it’s for a performance horse on a regular training regimen, choosing a feed balanced to meet the high nutritional requirements is very important. Feeding the horse a feed based on its life stage is usually the way to go as these feeds are formulated to have the appropriate levels of energy, protein, vitamins and minerals.

There are several other elements to consider when choosing a feed for your horse, the protein level of your hay being one of them. Testing your hay is key to know how to balance the rest of your horse’s ration.