Acid‐Base Alterations in Barrel Racing Quarter Horses of Different Fitness Levels Assessed Via The Simplified Strong Ion Approach

Abstract

IntroductionThe evaluation of acid‐base balance of horses is important because it detects alterations that affect their performance and health. There are studies relating these changes with endurance type effort, but few regarding sprint exercise. The purpose of this study was to determine whether the fitness level of Quarter Horses performing barrel racing could be differentiated by quantitative acid‐base analysis.MethodsFor this purpose, 10 horses were distributed into two groups: high (HF) and lower (LF) fitness as defined by the trainer. GPS and frequency meter were used for the measurements. Venous blood gas analysis was performed using a portable analyzer (I‐stat) before and after exercise. Strong ion difference (SID), anion gap (AG), strong ion gap (SIG) and concentration of non‐volatile buffers (Atot) were determined. Variables before and after exercise were compared within and between groups by t‐test (P<0.05).ResultsThe average track distance was 125 m. There were no differences between maximum or average velocity and heart rate, which were 30.76 ± 0.53 km/h, 22.85 ± 0.28 km/h, 206 bpm ± 3.91 versus 27.7 ± 2.4 km/h, 21.94 ± 0.3 km/h and 203 bpm ± 5.77 for the HF and LF groups, respectively. SID values before exercise were significantly lower for the LF group. Both groups showed a significant increase in Atot and AG, while pH, HCO3‐, SIG and SID decreased significantly after exercise.ConclusionsMetabolic acidosis was observed using both the traditional and the quantitative approach. It was not possible to differentiate the fitness level of horses in the study.Ethical Animal ResearchAll procedures were approved by the institutional animal care and use committee of the university (CEUA, Process: 008481/11). Explicit owner informed consent for participation in this study is not stated. Sources of funding: UNESP Reitoria (PIBIC). Competing interests: none.