Hematological and cardiac alterations in Arabian horses submitted to incremental effort test in treadmill

Abstract

Alterations in heart rate and hematological variables of Arabian horses submitted to intense exercise in treadmill under tropical conditions were studied. Twenty four trained horses were adapted to exercise on a high performance treadmill and then submitted to an incremental (4; 5; 6; 7; 8; 9 and 10 m.s-1) exercise test. Heart rate was verified and blood samples were taken 15 seconds before the end of each exercise step to determine the hematocrit, concentration of leucocytes, erythrocytes and hemoglobin. From these data the mean corpuscular volume (MCV), the mean corpuscular hemoglobin (MCH) and the mean corpuscular hemoglobin concentration (MCHC) were calculated. The results show that there were significant variations in heart rate and hematimetric variables from the rest when compared to the values after the exercise. The hematological indexes MCV and MCH had also increased significantly in the stage of maximum effort (10m/s) demonstrating the occurrence of anisocytosis during the intense exercise. In such a way, the degree of the alterations of these physiological variables is related with the intensity and duration of the effort.