Protein: Not just for Body Builders

Protein: Not just for Body Builders
5 July 2017 | Foran Equine


Protein is an essential part of any performance or exercising horses’ diet, it is required to build and maintain muscle mass.

In the wild, horses are natural grass grazers, so you may be questioning why they need protein at all in their diet?

Protein is an essential part of any horse’s diet and particularly performance or exercising horses. In adult horses up to half their bodyweight is from the protein present in their body, over half of which is their muscles. As the building blocks of protein cannot be completely synthesised in the body, it requires a significant dietary intake of protein to build all that muscle.

Crude Protein Content

Most horse owner are familiar with the number or percentage of their horse feed, example “12% mix”, and that the number refers to the protein content of the feed. In fact it represents the percentage of crude protein present in the feed. The protein content of grass and hay however, is very variable. Typically lush spring grass is high in protein, but this decreases as the grazing season progresses. The protein content of hay is even lower than that of grass.

As all proteins are not created equally, the protein content alone  should not be assessed in your horse’s diet; we must also consider the protein quality and protein digestibility.

Protein Quality

Proteins are made up of amino acid molecules linked together in. The combination of amino acids and their concentration in a protein directly impact the proteins quality. Some amino acids are rarer than others. Furthermore, certain amino acids cannot be made by the body (“essential amino acids”). Where a protein is both rare in the diet and cannot be made by the horse, it can become a “limiting amino acid”. A limiting amino acid is one, which if in short supply, will limit overall protein production, even if other amino acids are available in sufficient quantity.

A protein source that is high in limiting amino acids for a horse is considered a high quality protein source for horses. The limiting amino acids for horses are; lysine, threonine and methionine. A rich source of these proteins is soya bean meal.

Protein Digestibility

Crude protein percentage is the most common means of comparing protein content of feeds in the UK and Ireland. In continental Europe however, feed protein values are often expressed in digestible protein percentage. This is because, not all proteins are easily digested. If the protein cannot be digested in the small intestine, it is not absorbed for use by the horse.

Protein sources that can be digested before entering the large intestine are regarded as having good digestibility and include products such as cooked horse pellets.

Protein for Young Horses

The thoroughbred horse has the potential to reach 90% of its mature weight at 18 months. Heavier breeds take longer. The fact remains, horses have the potential to reach skeletal and body maturity at a young age. This potential can only be reached if the husbandry conditions and particularly the dietary intake are favourable to achieving it.

The first limiting nutrient for horse growth is the energy content of the diet. Where energy needs are not met by the diet, the animal cannot grow at optimum growth rates. Even a modest straight grain feed can provide sufficient energy for growth in young horses.

The next limiting nutrient however, is protein. A diet low in protein content or which has poor quality or poorly digestible protein will significantly limit growth rates in young horses.

Interestingly, repeated scientific studies have demonstrated that supplementation of poor quality or low protein diets with a small amount of limiting amino acids can significantly improve growth rates. And reverse previously poor growth rates with compensatory growth following supplementation.

Protein for Performance Horses

It is no secret that exercise leads to muscle growth and muscle development requires protein. Most horses when they begin their training require an increased intake of protein to meet the needs for muscle development. Once the horse has developed the muscle, it continues to have an on going higher protein intake requirement to maintain the musculature.

Typically the increased protein requirements are met by increasing the volume of feed, in line with the increased energy needs of the horse. There are cases however, which may benefit from protein supplementation such as;

  • Horses that don’t eat well
  • Horses that go off their feed during competition
  • Horses that have a long competition season
  • Horses returning to competition after illness
  • Horses that were of an immature body type at commencement of training

Protein Supplementation

As protein content is the most expensive component of any diet, protein supplementation should be considered carefully before using. When weighing the options regarding protein supplementation it is important to consider the points discussed above on protein content, protein quality and protein digestibility.

Foran Equine’s protein supplement range; Pro Am contains a high content, high quality, pre-digested liquid protein formulated for use in horses. It has very high crude protein content at over 38% in our original Pro Am product.

The products are derived from natural plant sources, with a high content of limiting amino acids.These plant proteins are processed with enzymes replicating the natural digestive process in the intestines. Thus the protein used in the Pro Am range is pre-digested and readily available for absorption directly on ingestion.

Protein is an essential nutrient for all horses. Specific protein supplementation can be particularly useful for young growing horses or horses undertaking intensive exercise, by providing the necessary building blocks to create and maintain muscle mass.