Venous Blood Acid-Base Status in Show Jumper Horses Subjected to Different Physical Exercises

The aim of this study was to assess whether acid-base profile exhibits changes in regularly trained show jumping horses undergoing increasing exercise workloads. Seven female Italian saddle horses were subjected to three different physical exercise trials of increasing workload identified as three exercise phases (EPs). During EPI horses were subjected to a standardized exercise test consisting of 15 minutes of treadmill, during EPII horses were subjected to a show jumping test (height, 0.9–1.1 m; course length, 300 m), during EPIII horses underwent two jumping sessions carried out over two consecutive days. Blood samples were collected at rest (TPRE), after exercise (TPOST), and 30 minutes after the end of exercise (TPOST30). The values of pH, partial pressure of carbon dioxide (PCO2), partial pressure of oxygen (PO2), bicarbonate level (HCO3−), hemoglobin (Hb), and hematocrit (Hct) were measured. A significant effect of exercise workload and time (P < .001) on PO2, PCO2, HCO3−, Hb, and Hct values was found. The variation in the studied parameters resulted mostly reversible within TPOST30 in horses when subjected to EPI and EPII, whereas PO2, Hb, and Hct remained higher at TPOST30 than TPRE in horses when subjected to the second day of jumping section (EPIII) indicating a failure to recover. The results suggest that jumping sessions carried out over two consecutive days represent extra workload for horses, and this should be taken into account by veterinarian to prevent acid-base imbalance and for the maintenance of health and performance in equine athletes.