Survey of the occurrence of equine deep digital flexor tendon contraction (clubfoot) in the main thoroughbred breeding area in Japan.

This study investigates the prevalence of clubfoot, a condition characterized by contraction in the deep digital flexor tendon, in thoroughbred foals in Hidaka District, Hokkaido, Japan. The researchers found the occurrence of clubfoot higher than expected, demonstrating the need for improved diagnostic techniques and guidelines.

Study Design and Participants

• The study was conducted at 114 ranches in Hidaka District in Hokkaido, Japan. The district represents a main breeding area for Thoroughbred horses.
• The researchers examined a total of 1,118 Thoroughbred foals that were born within a six-month period, from January to June 2003.
• The examination of the foals’ feet for clubfoot was carried out at different times from May to September of the same year.

Findings on the Occurrence of Clubfoot

• The researchers detected clubfoot in 179 of the 1,118 foals, representing 16 percent of the total population sampled. This incidence was observed across 89 ranches, which accounted for 78 percent of the total number of ranches involved in the survey.
• Of the 179 foals diagnosed with clubfoot, 124 (which is 69.3 percent) were assessed as having grade II or higher clubfoot. This grading system likely refers to the severity of clubfoot, with grade I being the least severe.
• The researchers speculated that grade I clubfoot might get overlooked or could rapidly advance in severity.

Implication of the Findings and Suggestions

• The study revealed that the occurrence of clubfoot was more frequent than what the researchers had anticipated in the region under investigation.
• In light of these findings, the authors suggested there is a need to establish accurate diagnostic techniques and develop guidelines for managing clubfoot. This approach could help minimize the impact that this condition has on the health and development of Thoroughbred foals.