Your Guide to Equine Health Care

Protein Primer

Learn more about these complex molecules that help the horse’s body systems function properly in this article from the October 2022 issue of The Horse.

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young horses in pasture
Actively growing horses have very high protein requirements due to cellular growth and rapidly building body tissues. | Getty Images

We simplify these complex molecules that help the horse’s body systems function properly

From muscle development to coat and hoof quality and everything between, protein plays crucial roles in keeping a horse’s body functioning properly. But proteins and their components can be challenging to understand, and most classes of horses require different protein amounts to remain healthy, grow optimally, produce and give foals the best start to life, and/or perform at their best.

The good news is while protein might seem complicated, it doesn’t have to be. Here’s a primer on all things protein.

What is protein and why is it so important?

“Proteins are chains of amino acids,” says Kristine Urschel, PhD, an associate professor of equine science in the University of Kentucky’s Department of Animal & Food Sciences, in Lexington.

Twenty-one amino acids, in different combinations, make up the various proteins the body uses. Horses’ bodies can produce some of these—termed nonessential amino acids—while they must obtain the rest—called essential amino acids—from the diet. Essential amino acids include phenylalanine, histidine, isoleucine, leucine, methionine, tryptophan, valine, and lysine.

“With the exception of water, protein is the most abundant nutrient in every part of the horse’s body,” says Carol Layton, BSc, MEd, an equine nutritionist at Balanced Equine, in Cobark, New South Wales, Australia. “Protein is a key component of hooves (including more than 90% of the hoof wall), along with muscle tissue and hair.”

It also helps several of the horse’s body systems function properly, playing key structural, metabolic, and regulatory roles: “The major components of muscle that allow it to contract, actin and myosin, are proteins,” Urschel says. “Enzymes that catalyze all of the body’s reactions are proteins, and many neurotransmitters are proteins.”

Amino acids themselves have additional roles, such as serving as fuel sources for cells to create cellular energy and aiding in the synthesis of some hormones and neurotransmitters, Urschel

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We at The Horse work to provide you with the latest and most reliable news and information on equine health, care, management, and welfare through our magazine and Our explanatory journalism provides an understandable resource on important and sometimes complex health issues. Your subscription will help The Horse continue to offer this vital resource to horse owners of all breeds, disciplines, and experience levels.


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Written by:

Erica Larson, former news editor for The Horse, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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