THE EFFECT OF SYSTEMATIC TRAINING ON PLASMA ELECTROLYTES, HAEMATOCRIT VALUE, AND BLOOD SUGAR IN THOROUGHBRED RACE HORSES

Abstract

Experiments were carried out on regularly ridden horses and thoroughbred race horses following a 10- to 40-minute training period for both groups and following 1- to 3-minute racing in the latter group. An increase was observed in the concentration of calcium in serum and in the concentration of potassium, inorganic phosphorus, and iron in plasma. In the trained race horses a considerable increase was noted in the haematocrit (Hct) value and in the haemoglobin (Hb) concentration of the blood, average values after the race being 23 g% and 66% respectively. In regularly ridden horses and in thoroughbred horses which were not in training, similar muscular exercise did not produce such a noticeable increase in the Hb concentration. Sixteen to twenty-four hours after a race or exercise a transitory, quite pronounced hyperbilirubinaemia of 3 mg% was observed. A large part of the mobilized red cells was not restored, but disintegrated, causing a transitory hyperbilirubinaemia. In blood samples drawn immediately after the race, the average fragility test value of the red cells increased, haemolysis occurring in 0.63% NaCl solution. Blood samples taken from thoroughbred horses after exercise and racing were hyperglycaemic while the blood sugar levels in exercised, regularly ridden horses were not significantly increased and even decreased following exhaustive galloping.These experiments support the hypothesis that the hyperglycaemia is the result of an emotional factor influencing a conditioned nervous response. Thus race horses differ from untrained, regularly ridden horses in that the former show reflex red cell mobilization and hyperglycaemia while the latter do not.