A survey of white line disease in Japanese racehorses.

This study analyzes the occurrence of white line disease (a hoof condition) in over a thousand Thoroughbred racehorses from the Japan Racing Association’s Miho Training Center during the 1996 season. Various factors like age, sex, number of diseased horses and hooves, lesions’ locations and size were considered to understand disease prevalence and characteristics.

Survey Methodology

• The research was conducted by examining 1781 racehorses during their regular shoeing process by farriers (professionals who trim and shoe horse’s hooves).
• The objective was to identify horses still showing signs of damaged white lines on their hooves, indicative of white line disease, despite regular hoof trimming.
• The diagnosis of the disease was not based on random sampling but on visible hoof damage after regular trimming.

Data Gathered

• Various factors were noted for each horse, including age, sex, and number of diseased hooves.
• The severity of the disease was determined by the number of lesions found around the bearing borders of the hoof, as well as their length.

Observations and Findings

• A total of 11.5% of all horses surveyed (204 animals) were found to have white line disease.
• Incidence of the disease showed a significant increase with the horse’s age (P less than or equal to 0.01).
• No significant difference was found in disease incidence based on the sex of the horses.
• White line disease was observed more commonly in the front hooves than in the hind hooves of the affected animals.
• The disease lesions developed more frequently around the toe area compared to other regions of the hoof-bearing border.
• Most of the damage was measured to be 20 to 30 mm in length.

Significance of the Study

• The findings of this survey shed light on the prevalence and disease characteristics of white line disease in Thoroughbred racehorses in Japan, which could be used to improve equine health and welfare strategies.
• The strong correlation between age and white line disease could demonstrate a need for more focused hoof care in older horses.
• The location and frequency of lesions add to the understanding of disease behavior, potentially influencing prevention and treatment strategies.