COMPARISON OF AEROBIC CAPACITY BETWEEN RACING STANDARD-BRED HORSES

A standardized treadmill test was used to compare metabolic and ventil atory measurements between 10 standardbred racehorses. The horses were divided into two groups: group A (n = 5) had mean racing speeds of 4. 4 s faster than group B (n = 5) over a 1-mi. distance. Each horse was fitted with a venous catheter and connected to a valved gas-collection system. The exercise test consisted of 1-min incremental workloads ra nging from 4.0 to 12.0 m/s at a treadmill incline of 3 degrees. Group A had significantly higher (P < 0.05) measurements of maximal O-2 cons umption (VO2max), O-2 pulse, and tidal volume. Venous lactate concentr ation and respiratory exchange ratio measured at Got,, were also signi ficantly higher (P < 0.05) in group A. Similar treadmill velocities we re required to achieve a respiratory exchange ratio of >1 and venous b lood lactate concentration of >4 mmol/l; however, group A was able to complete a significantly higher (P < 0.01) number of workloads before fatigue. The high aerobic and anaerobic capacity of group A horses may be a major contributor to a faster racing performance.