Why amino acids are important to your horse’s diet

Gaining a better understanding of the different amino acids and how they work will help you better plan your horse’s diet, and ultimately help him thrive!

Has a horse ever turned your head? You see the shiny coat, and maybe he has dapples that glisten in the sun. His back looks strong and solid and there’s a gleam in his eye. Maybe he’s born with these qualities; or maybe they’re due to hours of impeccable grooming practices and years of training. All these factors are involved, but many horse caretakers don’t realize that nutrition also plays a part! Most people could probably rattle off the protein levels, fat content, and perhaps even the basic minerals included in their horse feeds — but what about amino acids? There probably isn’t a more important nutrient than amino acids for making horses look and feel their best.

What are amino acids?

Amino acids are organic compounds, including nitrogen, carbon, hydrogen and oxygen, that combine to form proteins. When proteins are digested or broken down, amino acids are left. Protein and amino acids are often referred to as “the building blocks of life”.

There are two basic categories of amino acids: essential and nonessential. Essential amino acids must be provided in the diet, as horses cannot create them on their own in the digestive tract, where the nonessential amino acids are made. These key amino acids are needed in specific amounts and ratios in order to properly maintain the structure of the horse’s body.

The horse requires ten essential amino acids:

  1. Phenylalanine
  2. Valine
  3. Threonine
  4. Tryptophan
  5. Isoleucine
  6. Methionine
  7. Histidine
  8. Arginine
  9. Leucine
  10. Lysine

There are also “limiting amino acids”. If a horse runs out of this type of amino acid, he can’t utilize any of the remaining amino acids present in the feed. If the horse has enough of the first most-limiting amino acid, but then runs out of the second most-limiting amino acid, he can’t use the remaining amount of the third most-limiting, and so on. Liebig’s Barrel (see image at right) is a model that illustrates this concept.

In horses, the first three most-limiting amino acids are lysine, methionine and threonine. Increasingly, these three amino acids are listed on the guaranteed analysis of horse feed tags, as they are an indication of the quality of the protein sources and the balanced nature of the feed. Generally speaking, if these three amino acids are present in sufficient quantities, the ingredients used also provide the remaining amino acids in sufficient quantities.

Let’s dig deeper and take a look at how amino acids work specifically in horses.

Amino acids build strong horses

If your horse is on a diet calculated to have adequate “crude protein”, but essential amino acids are not present, he simply cannot use the protein to build and maintain muscle, hair, hoof and skin, and you will see changes in his appearance, such as loss of muscle mass, rough hair, and unhealthy hooves.

Virtually every structure of the horse is built from amino acids. A horse’s hair and hooves are made up of 95% amino acids. Muscle, the engine that powers your horse, is 73% amino acids. Bone, the all-important structure that supports your weight and your horse’s, and needs to develop correctly and strongly from birth, is built from 30% amino acids. In short, a horse is made from amino acids, which is why those with the best amino acid intake look great and perform to their highest potential.

A horse is made from amino acids, which is why those with the best amino acid intake look great and perform to their highest potential.

A key topline contributor

For the horse’s topline health (the area that runs from the withers to the hindquarters), amino acids are the name of the game. Ensuring the right input of amino acids through proper nutrition will go a long way to growing larger muscles and impacting overall body composition.

If you are looking for a feed that may help your horse’s topline, be sure to read the guaranteed analysis on the feed tag. The amino acid levels should be called out and guaranteed. If the amino acids are included in specific amounts and ratios, they help support the horse’s structure, specifically the topline.

Looking for guaranteed amino acids on feed tags is a good starting point, but you then need to let the horse tell you if the feed is working by regularly evaluating and noting changes in his topline condition. Using a topline evaluation score (TES) is an effective way to measure if your horse is getting the nutrition he needs. Visit horsefeedblog.com/2016/10/identifying-evaluating-your-horses-topline/ for more information.

Exercise must be balanced with sufficient amino acids

While exercise will certainly alter existing muscles, building new muscles is a different story. Amino acids must be present in sufficient quantities and balanced with adequate calories to rebuild or augment muscle tissue.

In fact, if a horse is worked hard but his diet lacks sufficient amino acids, existing muscle mass can shrink. This can be a slippery slope in some situations, and as muscle atrophy sets in, the belief is that the horse needs to work even harder when in fact the fuel is not there in the form of nutrition to help support and repair tissue that is broken down with exercise.

Just like human athletes, equines athletes need more essential amino acids than maintenance horses in order to maximize the effects of training and allow them to look and feel their best.

Just like human athletes, equine athletes need more essential amino acids than maintenance horses to maximize the effects of training and allow them to look and feel their best.

Certain exercises thought to improve topline include hill work, backing exercises, and those that encourage the horse to collect and arc the body.

These exercises can help condition his muscles, but only if the diet is supporting the muscles through proper nutrition. Before you put your horse into a conditioning program, be sure his diet is in balance and you’ll be much happier with the results.

Amino acids are a key component to the horse’s overall health and wellness. Be sure to review your feeding program to make sure your own horse is getting everything needed to live his best life.