Understanding Protein

What are amino acids? -

Amino acids are the building blocks of protein and are vital for the horse to carry out processes within the body such as -

• • Muscle growth and development
  • Production of further amino acids
  • Hormone production – for regulation of bodily functions and development
  • Neurotransmitter production – for optimum nerve, muscle and gland function
  • Production of enzymes for optimum digestive health and function
  • Production of cytokines to control inflammation within the body and regulate the immune response

Essential & Limiting Amino Acids – essential amino acids cannot be made by the horse therefore are ‘essential’ to provide from the diet. These are arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Lysine, methionine and threonine (in this order) are the top 3 essential amino acids in most demand during protein synthesis in the horse. A limiting amino acid is one that if it became deficient, it would limit the production of further amino acids and protein synthesis in the horse. Lysine is typically the first limiting amino acid in the horse, as it is a key building block for making further amino acids and proteins.

Non-Essential Amino Acids – Non-Essential amino acids are those the horse can produce itself within the body. There are 11 non-essential amino acids in the horse. If the horse’s diet is deficient in essential amino acids, these non-essential amino acids cannot be produced to their full extent

Protein Requirements -

The NRC provides the following equation for calculating daily crude protein (CP) requirements for a mature, idle horse:

Body weight (in kg) x 1.26 g CP/kg BW/d.
For a 500kg horse this works out at 630g CP/ day.

The minimum amount of lysine required is recommended at 18 grams per day for a 500kg horse at maintenance. However, optimal lysine intake levels are estimated to be 27 grams per day for a 500kg performance horse.

Reminder! - This would include the crude protein and lysine present in grass, forage and concentrate feed!

For example - Typical range of average UK hay is 6-10% protein. This means that a 500kg horse on the minimum daily intake of 1.5% of its bodyweight in kg (7.5kg) is receiving an estimated 450-750g of protein from its hay per day. This can vary depending on the type and quality of the hay! The estimated average amount of lysine in typical UK hay is 0.25%.

Feeding to help build muscle and topline –

• Essential Balancer and Competition-Fit Balancer for the good doer
• Stamm 30 and Level-Grow mix
• Condition- Improver cubes and Condition-Improver mix
• Enduro-Performance

Although the development of muscle and topline can be assisted through the increase of quality protein in the diet, this development will not be observed without the correct workload to support your horses muscle growth.

Exceeding Protein Intakes -

When too much protein is fed, the horse will break it down and excrete it as urea. There is no current evidence to show that excess protein in the diet has a directly detrimental effect on the horse’s health, however it is proven in other animal species that an excessive protein intake can adversely affect kidney function. When feeding horses with signs of compromised kidney function, we should be considering the amount of protein present within the diet to reduce the risk of further strain on the kidneys.