Relationship of body condition score to completion rate during 160 km endurance races.

Three-hundred and sixty horses, primarily of Arabian breeding, age 5-22 years and body conditions scores 1.5-5.5 (on 1 to 9 scale as described by Henneke 1985), participated in one of two 160 km endurance races over the same course in August 1995 and July 1996. Condition score, cannon bone circumference, combined rider and tack weight, heart girth and body length were measured 11-18 h prior to the start of the event and bodyweight estimated according to the formula by Carroll and Huntington (1988). A rider weight ratio was calculated as rider weight divided by horse bodyweight. Rider weight and rider weight ratio had no effect on overall completion rates among all horses (P > 0.05). Among horses successfully completing the course, rider weight and rider weight ratio had no effect on finish time or placing (P > 0.05). Among horses who were eliminated, rider weight and rider weight ratio had no effect on miles completed before failure (P > 0.05). Condition scores had a significant effect on completion rate (P < 0.001). Distance successfully completed increased 31.81 km (19.88 miles) for each incremental increase of 1 in condition score (P < 0.001). Within the group of unsuccessful horses, there was a significant difference in condition score between horses who failed due to metabolic and nonmetabolic factors (P < 0.001). It was concluded that condition score is a more important factor in endurance performance than has been previously believed, and that condition score is a more important factor than is the weight of the rider, or the rider weight in relation to the weight of the mount.