Many horses are affected by lameness each year, with a large number of these horses being examined and treated by veterinarians. According to the 2015 USDA National Animal Health Monitoring System (NAHMS) study on equine management and select equine health conditions in the United States, 67% of horse operations reported one or more lame horses within the past year. In this survey, about 60% of lame horses had lameness examination performed by a veterinarian.
Low-grade lameness is usually of less concern to horses that perform lower levels of athletic function; although early detection and identification of the cause of low-level lameness can lead to earlier treatment, resolution of lameness and return to previous function. Low-grade lameness is more concerning in horses that perform at speed (i.e., racehorses), jump over large obstacles over uneven footing (three-day event horses) or work over extended distances (i.e. endurance horses). Low-grade lameness may indicate the beginning of a larger problem, and if untreated, could lead to a catastrophic injury, which could result in end of career or end of the horse’s life. Thus, good screening tools are needed to identify early, subtle lameness to prevent low grade injury/lameness from developing into a catastrophic injury.
The mainstay of lameness and musculoskeletal injury diagnosis begins with a complete lameness evaluation. However, agreement among veterinarians on the affected leg and degree of lameness is poor for horses with low-grade lameness. Within the past 20 years, horse mounted gait analysis devices have been developed and have been shown to have better accuracy in the identification of low-grade lameness compared to visual examination by experienced veterinarians. Benefits of these systems are ease of use and the ability to be used on the farm.