Variability of Selected Biochemical Parameters in Young Stallions During the 100-day Performance Test

The aim of the study was to evaluate variations in biochemical blood parameters of stallions during a 100-day performance test. The study was carried out with 20 clinically healthy stallions aged 3-4 years. The degree of adaptation to exercise loads during a 100-day performance test was assessed three times: (I) on the first day of training, (II) on the 46th day of training, and (III) on the 97th day of training. Sample collection and basic clinical tests were performed before training (1), directly after training (2), and after a 30-minute rest (3). Venous blood samples were analyzed for the concentration of total protein, glucose (GLU), and lactate, the activity of lactate dehydrogenase (LDH), and creatine kinase (CK), and total antioxidant status (TAS). Postexercise changes in the analyzed parameters showed that the loads were of moderate intensity. As a result of the 100-day training, postexercise variation in GLU concentration and CK and LDH activity was lower than at the beginning, which indicates that the body was stimulated to adapt to performing exercise tasks. The resting level of TAS was also found to increase. The results obtained suggest that the stallions are well prepared for increasing exercise loads.