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The importance of protein for yearlings

In the run up to yearling sales, enhancing physical development is key to making sure that they stand out and look their very best in the sale ring. Protein is an important nutritional component for supporting optimal muscle development.

Why is protein important as I prepare my yearling for sale?

Walker exercise, hand walking, lunging and long-reining are all introduced to yearlings during sales prep to develop optimal muscular condition and a supple, active walk that will get them noticed in the sales ring.

These demands on such young horses require an increased and specific profile of nutrients to support the musculoskeletal system. This can bring its own difficulties though, as over-feeding can lead to over-conditioning (over-topping) or temperament issues.

One of the most important nutrients for yearlings or any growing horse is protein, it is needed to build and repair muscle, is vital to collagen and therefore bone integrity. The building blocks of proteins – amino acids – are digested and absorbed by the horse and incorporated into developing muscle. Some amino acids are described as ‘limiting’ for growth, as without them, muscle development cannot happen, the most well-known one is lysine. Studies have demonstrated that supplementation of weanlings or yearlings’ diets with limiting amino acids can significantly improve growth rates.1

Feeding a high protein diet is typically how the increased protein needs of yearlings are met. However, the protein content alone does not guarantee success in this area you must also consider the protein quality and protein digestibility. Quality is determined by the level of essential amino acids (those that the horse cannot make for itself) provided by the protein source. Providing a protein supplement can be a very efficient way of ensuring the supply of essential amino acids to your yearling.

Read more about protein for horses

When does my yearling need a protein supplement?

Supplementing protein in the diet can particularly work well for:

1. Yearlings that were of an immature body type at start of sales preparation

2. Yearlings that don’t generally eat well

3. Yearlings that go off their feed during sales preparation

4. Yearlings recovering from illness during sales preparation

Muscle Prep contains hydrolysed plant protein, providing readily absorbed essential amino acids for rapid muscle development. In addition, B vitamins promote protein metabolism and Vitamin E provides powerful antioxidant action to support muscle recovery and immune health. For best results, feed according to guidelines daily for 6 weeks ahead of the sale date.

For more information about supporting your yearlings, please contact the Foran Equine Team.


  1.  Mok CH, Urschel KL. Amino acid requirements in horses. Asian-Australas J Anim Sci. 2020 May;33(5):679-695. doi: 10.5713/ajas.20.0050. Epub 2020 Mar 12. PMID: 32164055; PMCID: PMC7206390.

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