The effect of long-term aerobic exercise on blood parameters in Arabian horses

The aim of the study is to describe the general nature of changes in hematological and biochemical parameters of the blood of Arabian horses during acute adaptation to prolonged aerobic exercise. The study was conducted on Arabian horses at a stud farm in the Leningrad Region from April to June 2025. Ten clinically healthy horses aged 6–10 years, undergoing age-appropriate stud training and competing in endurance events, were selected. The animals were kept under identical conditions and fed the same balanced diet. Blood biochemistry was performed in the laboratory of the Department of Biochemistry and Physiology at the St. Petersburg State University of Veterinary Medicine. Analysis of the obtained data revealed that after completing the competitive distance, Arabian horses exhibited a significant increase in the number of leukocytes, neutrophils, and monocytes, while the number of eosinophils and lymphocytes decreased, indicating the development of myogenic leukocytosis and a stress leukogram. In response to exercise, concentrations of hemoglobin, total cholesterol, urea, urea nitrogen, alanine aminotransferase, muscle creatine phosphokinase, cardiac troponin I, and thyroxine also significantly increase. Mares have higher testosterone levels at rest than geldings, but after exercise, they decrease and become lower than those of geldings, while geldings experience an increase in testosterone levels. However, at this stage, it is impossible to determine whether this dynamic is related to gender or exercise intensity.