Muscle Stress and Thermal Discomfort of Equines in a Brazilian Rodeo-Style Sport (Vaquejada)

This study aimed to evaluate the effect of the exercise performed under the semi-arid weather on horses submitted to a Rodeo-style Sport (Vaquejada) through hemogasometric, clinical, and thermographic variables. To conduct this study, a Vaquejada simulation test (VST) was conducted in agreement with the rules of the Brazilian Association of Vaquejada. Physiological, thermographic, hemogasometry, and biochemistry data were collected before and after a single race. After it, significant changes were observed for thermographic, physiological, hemogasometric, and biochemical variables. The general surface temperature (ST) and those by body region differed (P < 0.01) between pre- and post-exercise conditions. The RR, HR, CK, Lactate, K+, and AG increased (P < 0.01) after the exercise. A negative correlation between the maximum lactate concentration and the reduction (P < 0.01) of pH, HCO3-, TCO2, and EB was also observed after the exercise. No significant changes were observed in PO2, PCO2, SO2, and other serum electrolytes after the exercise. The thermographic profile evidences the environment of thermal, critical, and dangerous discomfort to which the animals are exposed. Thus, we believe horses used in this activity should not be submitted to consecutive and immediate exercises so that pathological complications from repetitive exertion are avoided.