PrintThis is the first article in the "Fix It With Feed" series. Check back every Wednesday, starting Jan. 26 for more articles on nutrition and how it affects performance.
Trying to decide which feed to give your horse can feel like clothes shopping—you squint to read the numbers on the tag, but you’re never quite sure if it’s a perfect fit.
But while size is the only number you have to decipher on your clothes, the tags on horse feed have a dizzying array of figures. It can seem like code-breaking as you try to ascertain which grain might be the best for your horse.
The first number on every feed tag is the protein percentage, yet feeds come with a wide range of protein percentages, anywhere from 8 percent to 16 percent. Then there are all the various stories about protein. Is more better? Will too much hurt your horse? Does it make a horse hot? Help a horse put on muscle? What does your horse need?
What Does Protein Do?
In order to know what percentage of protein best suits your horse, it’s important to understand the vital role protein plays in the horse’s diet. Protein is an integral part of every tissue and organ in the horse’s body.
“Most people are afraid of protein,” said Dr. Juliet Getty of Getty Equine Nutrition LLC in Bayfield, Colo. “But the horse has to have those amino acids in his system to replace tissues like skin, hair and hooves. It keeps his blood and systems healthy, and it builds muscle.”
A protein is a complex molecule composed of a wide array of building blocks or amino acids. All 22 amino acids are required to build body proteins, but some of these building blocks can be converted from one to another, while others must be provided in the diet. These are the essential amino acids. The percentage values of three of the most important of these—lysine, methionine and threonine—are commonly listed on feed tags. (See sidebar for more information about essential amino acids.)
How much tissue rebuilding a horse’s body does dictates his protein needs. A horse who lives in a pasture and goes for pleasure rides a few days a week doesn’t stress his muscles and tissues enough to require significant rebuilding. Therefore, he has a lower protein requirement.
A horse competing at a high level, with repeated stress to his body tissues, will need more protein in order to maintain and rebuild those tissues, especially muscle. A growing young horse has higher protein needs because he’s continually adding tissue and building muscle. Likewise, a broodmare—in the gestational and lactating stages—will need additional protein to support the demand the foal places on her body.
It’s important to note that protein is an inefficient energy source for the horse’s body. A horse’s calorie requirements might increase dramatically with intense work, but his protein requirements will stay relatively stable. Ideally, the horse’s body uses protein purely to maintain and rebuild body tissues, while using carbohydrates and fat as caloric energy sources.
Not many feed companies print the energy content, or megacalorie per kilogram, on the feed tag, but this is important information to consider when deciding a horse’s diet. Feeding more protein doesn’t add energy in a productive way; feeding more calories in the form of carbohydrates or fat does.
Where Does Protein Come From?
