C. F. BOLWELL, C. W. ROGERS, N. P. FRENCH, E. C. FIRTH Equine Veterinary Journal January 2012 44 1 20-24 Reasons for performing study: There is increasing evidence suggesting that early exercise in Thoroughbred racehorses may be beneficial to the development of the musculoskeletal system. At present, information on the exercise programmes and health problems of individual yearlings during a sales preparation is scant. Objectives: To describe the exercise and health problems of Thoroughbred yearlings during preparation for sales, and to identify variations in exercise between and within farms. Methods: A prospective cohort study was used to collect exercise and health information from 18 farms across New Zealand. Daily exercise records for individual horses were recorded during the studfarms' preparation for the annual national yearling sales in January 2009. Results: Data were collected from 319 yearlings, of which 283 (88.7%) were exercised (hand walking, mechanical walker and lungeing) during their preparations. Sales preparation lasted a median of 69 days (interquartile range 61–78) and differed significantly between farms (P<0.001). The median exercise time performed differed significantly by gender (P<0.001), farm (P<0.001) and month of the preparation (P<0.001), but not by type of sale (P = 0.14) or category of sales price (P = 0.12). Within certain farms, daily exercise differed between horses as did total exercise by gender and the number of days spent in the sales preparation. Lameness was the most common condition affecting yearlings and the overall incidence rate of lameness was 0.08 per 100 horse days (95% confidence interval 0.05–0.13). Incidence rates of lameness varied significantly between farms (P = 0.02), but not by age (P = 0.77), sales type (P = 0.58) or month of the preparation (P = 0.53). Conclusions and potential relevance: Yearling exercise programmes varied between and within farms. Since exercise is already being tailored for each individual horse, there may be an opportunity to allow for modifications to sales preparation with the future career in mind.

• Epidemiology
• Equine