Biochemical and hematological alterations in horses subjected to performance tests in a semiarid region

This study aimed to evaluate the hematological, physiological and biochemical alterations of quarter and crossbred horses subjected to vaquejada tests in semiarid regions and to determine the welfare conditions of the animals in these competitions. We evaluated 18 pure and crossbred Quarter horses, males and females, with ages ranging from two to 13 years and an average live weight of 476.5 kg, divided into three groups (animals in early training, animals in an intermediate phase and animals considered fit for competition). Four samples were collected at 30-day intervals. The physiological, hematological and biochemical parameters were measured at two time points: before, with the animal resting, and immediately after the vaquejada test simulation. The experimental design was subdivided into plots that were repeated over time (three types of training, two moments and four collections). The results were subjected to analysis of variance, and the means were compared via Tukey’s test at 5% significance. There was an effect of the moment of collection on the respiratory rate, hematocrit and glucose concentration. There was a marked increase in heart rate, approximately 25%, from the first collection to the subsequent collection, which remained constant until the last collection. The heart rates of the animals remained constant, but immediately after the test, the average heart rate of the animals at the beginning of training was lower than that in the other phases. More research is needed to determine the time at which physiological and biochemical parameters return to normal patterns and to predict possible injuries in the conditioning of horses participating in the vaquejada.