What Is “Colt Sore”?

“Colt sore” is a term used by trainers of young racehorses to describe a horse that is not progressing well in training, seeming uncomfortable and showing poor gaits but typically without any obvious source of lameness. This is often assumed to be caused by joint issues but that’s not necessarily the case.

The picture of being “colt sore” can happen at any age and in any discipline.  The most common cause is actually often overlooked completely – poor muscular adaptation. Signs of poor muscular adaptation include:

  • Poor muscular bulk
  • Tenderness on palpation
  • High resting muscle tone (hard muscles)
  • Failure to meet training milestones
  • Difficulty with more advanced movements or gaits
  • Resistance to work, appearance of vices or dangerous behavior

The horse is a tremendous natural athlete but wasn’t designed to do the sustained daily workloads we ask.  The goal of training is to stimulate strengthening and biochemical adaptations that allow the horse to do the required workloads. Part of this is inherent genetic potential, which we can’t change, but a large part is providing the targeted support which allows the horse to correctly respond to training, particularly in muscle which is the horse’s engine.

Muscle is protein, and amino acids are the building blocks of protein. Many people reach for protein when there is a muscle issue but you can’t build muscle or make it work more efficiently just by feeding more protein unless the diet is protein deficient. Even then you need high levels of specific amino acids (leucine, lysine, methionine) to make a difference.

Vitamin E and selenium in highly absorbable forms are critical to supporting the antioxidant defenses of the working muscle cell. Exercising muscle generates tremendous amounts of oxygen free radicals in the process of burning fuels for energy. The vitamin E protects membranes surrounding and inside the cells while selenium is important for maintaining activity of the most important antioxidant inside the cell’s fluids – glutathione.

Two scientifically proven supports for muscle metabolism are acetyl-L-carnitine and beta-alanine.  See this discussion for full details of their many benefits to muscle.

A common approach to a horse that is struggling despite the usual methods is to stop training and turn the horse out, which costs considerable time and money. Before going that route, try Muscle EQ. You will typically see results within 3 weeks.

Eleanor Kellon, VMD





About Dr. Kellon

Graduate of University of Pennsylvania Veterinary School. Owner of Equine Nutritional Solutions, www.drkellon.com, industry and private nutritional consultations, online nutritional courses. Staff Veterinary Expert at Uckele Health and Nutrition https://tinyurl.com/vdxfex5h .
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