Amino Acids and Horses: Why are Amino Acids for Horses Important?

Amino Acids and HorsesIn order to fuel, repair, and recover muscle, equine diets must optimally contain a superior amino acid profile, including all 10 of the essential amino acids.

Most horse owners can quickly name the crude protein level in the feed they provide their horses. But, what horse owners really need to know about is the amino acid content.

Protein is made up of amino acids, similar to how a chain is made up of links.

There are two basic categories of amino acids: Essential and nonessential.

Essential amino acids must be provided in the diet, as the horse cannot create them on its own in the digestive tract, where the nonessential amino acids can be made. Nutrena products that include Topline Balance help to provide the right kind and ratio of amino acids in each formula.

Another key point is that some amino acids are known as “limiting” amino acids. This means that if a horse runs out of this type of amino acid, it 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, it can’t use the remaining amount of the third most limiting, and so on.

In horses, the first three most-limiting amino acids, in order, are lysine, methionine and threonine. Generally speaking, if these three amino acids are present in sufficient quantities, the ingredients used also provide the remaining amino acids in sufficient quantities.

It is increasingly common to see these three amino acids listed on the guaranteed analysis of horse feed tags, as it is an indication of the quality of the protein sources and the balanced nature of the feed.

If you are looking for a feed that may help impact topline, be sure to look at the guaranteed analysis on the feed tag. In specific Nutrena feeds – SafeChoice products, ProForce products, and Empower Topline Balance – the amino acid levels are called out and guaranteed on the tag. The amino acids included in Nutrena’s Topline Balance products are included in specific amounts and ratios. Research has shown that this specific combination and type of amino acids help to support a healthy topline when fed correctly.

Guaranteed amino acids on the tag is a good starting point. You then need to let the horse tell you if the feed is working by regularly evaluating and noting changes in topline condition.

Does My Horse Need a Diet or Exercise Change?

During an Equine Nutrition class, a student requested an evaluation of her horse to determine if any diet or exercise changes were necessary. This case highlighted the importance of assessing a horse’s body condition, weight, and topline when considering adjustments to their diet or exercise regimen.

hand feeding red size representing Does My Horse Need a Diet or Exercise Change?

The Horse Evaluation

Appearance versus Muscle Coverage

The evaluated horse was a 4-year-old Warmblood gelding, measuring 17.1 hands and weighing 1350 pounds. At first glance, the horse appeared to be in good flesh, but upon closer examination, a lack of muscle and coverage in the withers and back areas was noticeable.

Current Diet and Potential Issues

The student shared that the horse’s current diet consisted of 20 pounds of first cutting hay per day and 8 pounds of locally grown oats. While the calorie content seemed sufficient, there was a deficiency in the amino acid balance. The student also mentioned recent saddle refitting and chiropractic visits due to the horse’s back issues.

Identifying the Need for Changes

Increased Workload and Nutritional Requirements

Considering the horse’s increased workload due to the transition to college, it was evident that additional fortification was necessary. A ration balancer was recommended to address the young horse’s dietary needs and help replenish his topline.

Challenge and Counterargument

During the evaluation, another student challenged the recommended dietary change. As an Equine Physiology major, she believed that working the horse in a more collected manner, engaging the hindquarters and developing the topline through exercise, would be sufficient. She perceived the horse as overweight and did not see the need for a diet change.

Understanding the Importance of Proper Nutrition

Comparing Diet Deficiencies

To explain the importance of proper nutrition, an analogy was drawn to a young child on a diet consisting solely of rice. Such a diet lacks essential amino acids, resulting in a rounded abdomen but a lack of muscle mass. In this scenario, simply increasing exercise would not lead to muscle development unless the diet is appropriately supplemented.

Listening to Your Horse

The horse’s physical condition and performance can serve as indicators of dietary deficiencies. Taking the time to observe and assess your horse’s body condition, weight, and muscle development can provide valuable insights into whether diet or exercise changes are necessary.

When considering diet or exercise changes for your horse, it is crucial to evaluate their body condition, weight, and topline. Deficiencies in amino acids or other essential nutrients can affect muscle development and overall health. By paying attention to your horse’s physical cues and seeking professional advice, you can make informed decisions to ensure your horse receives the appropriate nutrition and exercise for optimal well-being and performance.

Ready to ensure your horse is getting the optimum nutrition at feeding time, every time? Find the perfect feed formulated specifically for horse’s needs with our Feed Selector Tool.

Feed Selector tool

What are Essential Amino Acids in Protein, and Why Do They Matter?

Nutrition articles frequently refer to protein quality and essential amino acids. When we use the term crude protein, we are essentially talking about a calculation based on measured nitrogen. Protein is about 16% nitrogen by weight, so if we measure the amount of nitrogen and multiply it by 6.25, this gives us a measurement of crude protein. It does not tell us anything about the quality of the protein. If you tested pure nitrogen this way, it would be 625% protein!

Digestible protein is that amount of the protein that is actually digested by the animal. In an over simplified example, if you fed 100 grams of protein and measured 50 grams in the feces, the protein would be 50% digestible.

What is really important to simple stomached animals (horses included) is the content of essential amino acids in the protein. We commonly talk about 10 essential amino acids (EAA), the amino acids that must be in the diet as the animal cannot synthesize them. These are:

  • Phenylalanine
  • Valine
  • Threonine
  • Tryptophan
  • Isoleucine
  • Methionine
  • Histidine
  • Arginine
  • Leucine
  • Lysine

A common memory aid in many nutrition texts books is to use the first letters of these 10 as PVT TIM HALL. (All of you who had a non-ruminant nutrition course still remember this acronym!)

The other 12 amino acids can generally be synthesized in the body and do not need to be in the diet, although there must be a supply of appropriate substrate to produce them. Animal nutrition text books cover this topic in excellent detail.

Limiting Amino Acids
Limiting Amino Acids

When we talk about limiting amino acids, these are the essential amino acids most likely to be restricting the use of the total amount of amino acids present. In most species, lysine is the first limiting amino acid, with methionine and threonine close behind. We commonly talk about amino acids as the building blocks of protein. If you are once you run out of an essential amino acid, you cannot build any more animal protein and the rest of the amino acids are used inefficiently for energy.

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

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