The major mitigating factor is nutritional or mineral imbalances in the diet resulting in rapid growth the first year of life. These are high energy (carbohydrates) and protein diets. There are a variety of other reasons a young horse will develop OCD lesions such as trauma to a joint, higher than average body weight and heredity.
Young horses that are fed high-energy diets (carbohydrates) combined with high protein are more prone to OCD lesions. This type of diet is designed for maximum growth resulting in horses that grow too quickly. The ossification process of turning cartilage into bone cannot keep up and the cartilage detaches from the bone, resulting in the characteristic cartilage “flaps.”
Plotting out a foal’s growth pattern on a graph can help you recognize a growth spurt. You will want to track weight, girth and height on your chart. The growth lines should show a consistent, even and upward pattern. Spikes in the chart may indicate a need to adjust the foal’s diet.
While it is important to maintain a balanced diet for a foal or yearling, it is just as important to maintain a balanced diet for a pregnant or nursing mare.
When talking about minerals, don’t think of it as having too much or too little of one particular mineral. It’s all in the balance. The ratio of calcium to phosphorus should be 1.5 to 1. An imbalance of these minerals, calcium 2.5 to 1 phosphorus can result in weaker bones and loss of bone density in the long term.
Mineral and nutritional requirements change as your horse matures. The National Research Council Board on Nutrition Requirements for Horses has developed an interactive nutrition calculator that will help you determine the mineral and nutritional requirements for your foal, pregnant mare or mature horse. This should get you off to a good start in understanding your horse’s diet requirements including minerals, but as always it is best to consult with your feed supplier and their associated nutritionists.
Learn More: Treatment of OCD Lesions in Horses