Postmortem evaluation of homotypic variation in shoe characteristics of 201 Thoroughbred racehorses

Shoe characteristics of Thoroughbred racehorses that died or were killed at California race-tracks between August 1992 and July 1994 were measured. Percentage of agreement was used to compare shoe characteristics between limbs. Using χ² analysis, shoe characteristics were compared between horses grouped by age and sex. Toe grabs were present on 90.5% of horses, and rim shoes were present on 15.9% of horses. Heel traction devices were less frequent on front (2.5%) than rear (6%) hooves. Pads were present on 24.9% of horses, with bonded rim pads commonest. Special types of shoes were present on 5% of horses. Percentage of agreement between left and right front hooves and between left and right rear hooves was high (20/25 variables; % agreement ≥99). In contrast, percentage of agreement between left front and left rear hooves and between right front and right rear hooves was low (2/25 variables; % agreement ≥99). Presence of a pad was significantly associated with age, and several shoe variables (size, presence of a special shoe, overall wear matched) were significantly associated with sex.