Respiratory system output cannot be improved with any training; the respiratory system of the horse is the major limiting factor of athletic performance. Although ventilation increases during exercise, the respiratory response is insufficient to prevent the development of arterial hypoxemia. The degree of hypoxemia can be an indicator of the performance, but arterial blood collection is complicated and impractical on the race track. The aim of the present study was based on the need to have an appropriate method to assess respiratory function during exercise under field conditions. This study was established to explore the usefulness of venous blood gas measurements in exercise tests. Eleven clinically healthy thoroughbred horses were used in the experiment. The same incremental exercise test was performed by each of the horses. Between each steps venous blood was collected from the left jugular vein. Blood samples were placed in special syringes under anaerobe conditions and stored on ice cubes until analyzes were performed. The time between collection and the analysis was less than five hours. Testing the hypothesis, a linear mixed model was fit to the pvO2 data. The analysis was carried out in R 2.15.1 statistical software. The venous partial pressure of oxygen (pvO2) increased parallel with increasing exercise as was expected based on arterial blood gas values described in the literature. During the suspected period of arterial hypoxia (highest level of exercise), the pvO2 was significantly higher, compared to low level exercise values in the venous blood. The pvO2 value did change oppositely to paO2 which reflect the physiologic limitation of equine ventilation during exercise. Venous blood gas parameters are not completely reliable to evaluate respiratory function in a resting horse but can be useful during exercise. The authors prove that some respiratory changes can be detected with simple sampling methods being appropriate on race tracks.
|Number of pages||7|
|Journal||Magyar Allatorvosok Lapja|
|Publication status||Published - Oct 1 2013|
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