Osteochondritis dissecans (OCD) is a developmental orthopaedic disorder that affects various species. Thoroughbreds have high prevalence, as do Warmbloods and Standardbreds. The development of OCD involves both genetic and non-genetic factors. This di...
Osteochondritis dissecans (OCD) is a developmental orthopaedic disorder that affects various species. Thoroughbreds have high prevalence, as do Warmbloods and Standardbreds. The development of OCD involves both genetic and non-genetic factors. This dissertation aims to examine non-genetic factors of OCD, especiallyenvironmental risk, locomotor patterns during turnout, and surgical prognosis in Thoroughbreds on Jeju Island, Korea.
In Chapter I, a survey was conducted on 61 Thoroughbred stud farms in Jeju to assess the five-year prevalence of OCD and its relationship with environmental and management factors. The average OCD prevalence was 22.5%, consistent with international studies (20–25%). The joints most commonly affected were the stifle (46%), fetlock (31%), and hock (21%). Farms supplied with larger pasture areas per horse had significantly lower OCD rates (P < 0.05), whereas total pasture size and daily turnout time did not show significant correlations (P > 0.05). In Chapter II, the Global Positioning System (GPS) was used to examine the movement patterns of 40 weanlings (6–12 months). OCD-positive foals exhibited higher irregular speed fluctuations by the OWT (outlier ratio × weight grade) metric.In contrast, overall movement volume and the MWT (mean velocity × body weight)metric did not differ.
iv In Chapter III, the study compared 75 horses treated surgically with 257 siblings from the same dam, serving as controls, to investigate the surgical prognosis of OCD of the lateral trochlear ridge (LTR) in the stifle. Arthroscopy for OCD did not impair the sale price or overall racing performance, including first-start rate, average race points, lifetime earnings, or retirement age, between the groups. However, the surgical group tended to debut later, had shorter careers, and had fewer total starts. Providing adequate pasture space at turnout and maintaining regular exercise while minimizing variability in speed may help reduce the risk of OCD. Moreover, timely surgery for OCD removal can maintain future athletic potential. The results of this dissertation provide the development of management and prevention strategies specific to Korea's Thoroughbred breeding sector.