Osteochondrosis (OC) is a developmental orthopedic disease (DOD) commonly diagnosed in growing horses. The disease is caused by abnormal cartilage development within one or more joints, resulting in lesion formation. The severity of the disease can range from mild to severe, however most cases require surgery to prevent further damage to the joints. The hind limb joints are most frequently affected.

Epidemiology

Osteochondrosis occurs most frequently in Standardbreds, Warmbloods and Thoroughbreds. The prevalence of osteochondrosis in Dutch Warmbloods between 1-4 years old is estimated to be about 25% of the population. In Thoroughbreds, the overall prevalence is 23%. Researchers from the University of Illinois and the University of Minnesota identified several genetic mutations associated with OC in a population of yearling horses born and raised on a single breeding farm in the United States.

Probable Causes

A wide range of different factors have been proposed as potential causes of osteochondrosis in horses---occurring individually or more than likely, a combination of the following:

• Nutrition
• Genetic predisposition
• Environmental factors
• Acute or repeated trauma
• Exercise program

Clinical Presentation

The presentation of osteochondrosis in horses differs depending on the site of involvement and on the stage of to which the syndrome has progressed.