Oxygen uptake evaluation in eventing horses at field tests

The aims of this study were to investigate the feasibility of measuring oxygen uptake (VO2) in eventing horses. Fifteen Brazilian Sport Horses were used in this study. The field exercise tests were performed on a dirt paddock of 320 m diameter. Tests consisted of continuous incremental speed exercise with five stages of three minutes each, with mean speeds of 1.7; 4.0; 6.0; 7.0 and 8.0 m/s. Gas collection equipment used was the commercially available portable breath-by-breath and flow spirometry metabolic measurement system. Data collection lasted 15 minutes. Least-square means were calculated for all variables with Tukey-Kramer method. The significance threshold was set at P<0.05. The portable equipment was well tolerated and the field test was successfully performed by all fifteen horses. The respiratory rate, tidal volume, VO2 and VCO2 mean values increased with proportionally to the speed and significant differences appeared among all steps. Measurement of oxygen consumption can be performed/assessed during field tests to evaluate the fitness of eventing horses.