Blood gas profile of horses disqualified from endurance races

Venous blood gases and components from 15 horses disqualified after completing 30, 40, 60km or 72, 90 and 140km endurance races are described. Horses were evaluated before any intervention to promote recovery. Partial oxygen pressure, carbon dioxide, oxygen saturation, bicarbonate ion concentration, pH, hematocrit and total plasma protein in venous blood were measured. Adaptive metabolic and respiratory responses were observed as a result from dehydration induced by racing as well as obvious changes in hematocrit and TPP. Increase in hematocrit values and total plasma proteins revealed a moderate hypovolemia due to exercise. Blood gas analysis results were not different between groups and were similar to horse finalists in other endurance races. We assume that different racing distances were not determinants for disqualification whereas individual fitness level was.