A survey of white line disease in Japanese racehorses

A survey was carried out into white line disease in 1781 Thoroughbred raceh orses kept in stables at the Japan Racing Association (JRA) Miho Training C enter (MTC) September-October 1996, The survey was conducted while horses w ere being shed by farriers, The horses that still exhibited damaged white l ines after regular trimming were diagnosed as having white line disease. Th e factors recorded were age, sex, number of diseased horses, number of dise ased hooves, number of lesions by region over the bearing border of the hoo f and the classified length of such lesions. The percentage of total diseas ed horses was 11.5% (204 animals), with incidence increasing significantly with age (P less than or equal to 0.01). Occurrence was independent of sex (P>0.05) was more frequent in the fore- than in the hindhoof and developed more frequently at the toe than at any other region of the forehoof-bearing border. Most lesions ranged from 20 to 30 mm in length.