Before purchasing a yearling it's important to review his health records to ensure he is healthy and sound enough for a successful racing career. Jennifer L. Higgins, DVM, gave potential buyers insight into specific lesions that could reduce a horse's career earnings when she presented a retrospective study on the subject at the 56th Annual Convention of the American Association of Equine Practitioners, held Dec. 4-8 in Baltimore, Md.

Higgins, an associate veterinarian at Northern Lakes Veterinary Hospital in Ashland, N.H., completed the study with a team from Rood & Riddle Equine Hospital in Lexington, Ky., when she was an ambulatory intern. The team reviewed more than 5,000 radiographs of Thoroughbred yearlings offered for public sale from 2004 to 2007. They examined bone fragments located in the back of the horses' knees on the articular surfaces of the accessory carpal bone that were previously considered to be a mild problem, hoping to determine whether these fragments affected racing prognosis.

The researchers narrowed their focus to 45 yearlings that met their inclusion criteria. Of these 45 case studies, 23 horses had lesions in the left knee, 19 in the right, and three had lesions in both knees. Due to the retrospective nature of the study, there was no way of knowing how or when the horses sustained the lesions.

They then pulled complete race records on the 45 horses, mainly focusing on the number of starts, earnings per start, and career earnings