Long-Term Changes of Physiological Reactions in Young Lipizzan Stallions During Exercise Testing

The aim of the study was to determine the fluctuations of selected physiological parameters in young Lipizzan stallions (n = 10) during the initial phase of their training as indicators of adaptation to a graded exercise load and stress exposure. For this purpose, four exercise tests (ExT) with lunging were carried out over a period of one year. Physiological parameters (gait speed, heart and respiratory rate (HR and RR), rectal and body surface temperature (RT and BST), and cortisol and lactate concentration (CORT and LAC)) were measured before and after training. In all ExT, gait speeds increased (p < 0.001) during the transitions from walk to trot and canter, followed by a significant (p < 0.001) increase in HR, RT, BST, and CORT, but not LAC values. However, the gate speed has no influence on the measured parameters. The highest BST values and corresponding warming were measured in the cranial region, followed by the caudal and distal body regions. The values of the measured variables remained within the ranges for warm-blooded horses, indicating adequate adaptation of the stallions to the applied stress level, but their variations could depend on air temperature or humidity. The results presented contribute to the knowledge of the complex physiological processes that occur in horses during exercise and point to the importance of environmental factors for adaptation to exercise.