Oxygen Uptake And Ventilatory Thresholds In Endurance Horses With Different Fitness

RIBER CC, MUÑOZ AM, TRIGO P, CASTEJÓN F, DÍEZ M, RIBER C

Budapest

Congreso; 13th WEVA Congress; 2013

World Equine Veterinary Associaton

Introduction. Oxygen uptake (VO2) appears to be correlated with athletic performance in Thoroughbred (Young et al., 2002) and Standardbred horses (Gavreau et al., 1995). Objective. To evaluate whether fit endurance horses have higher VO2 and ventilatory thresholds than unfit endurance horses. Methods. Twenty-nine endurance horses were subjected to a treadmill exercise test. Warming-up consisted in walking (5min) and trotting (5 min), with the treadmill flat. The test started at 5 m/s for 3 min, with a slope of 6%. After that, the speed was increased by 1 m/s every 3 min until the horse was unable to keep the pace. Time of exercise was monitored. Horses wore a respiratory mask and ventilatory parameters. VO2 and CO2 production (VCO2) were obtained. Ventilatory aerobic and anaerobic thresholds (VAT and VAnT) were calculated by the V-slope method, according to the method described by Beaver et al. (1986). This method is based on the linearity between VO2 and VCO2 under the aerobic threshold. Horses were divided into two groups: A (n=19), in active training and B (n=10), at the onset of training. Results and discussion. Time of exercise to fatigue (without considering warming-up) was significantly longer in group A than in B (780.9 vs. 646.8 sec). Eleven horses of A were able to complete the workload of 8 m/s, seven horses achieved 9 m/s and one horse, 10 m/s. None of the horses of group B was able to complete the workload of 8 m/s. VO2peak (maximum value of VO2 during exercise) was higher in A (41.71 ml/kg/min vs. 33.14 ml/kg/min). Group A presented significantly higher VAnT (7.914 vs 7.102 m/s). However, VAT did not differ between fitness groups (5.937 m/s in A and 5.940 m/s in B). This last result could derive from the effect of excitation or locomotion, because at speeds of VAT, some horses were trotting and other galloping. Conclusion. Fit endurance horses had higher VO2peak and VAnT and they were able to run to fatigue longer on the treadmill than unfit horses.