The measurement of biomarkers that reflect cartilage breakdown is a powerful tool for investigating joint damage caused by disease or injury. Particularly in cases of osteochondrosis, synovial concentrations of these biomarkers may reveal the presence of osteoarthritic changes. Coll2-1, Coll2-1 NO2 and myeloperoxidase have recently been introduced in equine osteoarticular research but comparison between the concentrations of these markers in OCD affected and healthy joints has not been made. Therefore, this study aimed at reporting the synovial concentrations of these biomarkers in joints affected with osteochondral fragments in the tarsocrural joint compared to unaffected joints. Myeloperoxidase and Coll2-1NO2 revealed to have similar levels between affected joints and controls. However, in contrast to previous studies using C2C the present study demonstrated that synovial levels of Coll2-1 were significantly elevated in tarsocrural joints affected with osteochondrosis. Thus, Coll2-1 may be an earlier marker of cartilage degeneration than other cartilage degradation markers that have been previously used in equine medicine.