The Quarter-Horses regularly participate in non-traditional sports that simulate activities on cattle ranches. In the vaquejada races, the horses run at about 30 km/h, reaching maximum heart rates of around 200 bpm, indicating the great physical effort during competitions and with that could impact welfare. To test the hypothesis that vaquejada horses can be evaluated for the quality of welfare through a combination of non-invasive and invasive methods, an experiment was developed that aimed to assess the quality of welfare through thermography and blood biomarkers before and after vaquejada races. Ten vaquejada horses, which were in regular competition, were submitted to the vaquejadas racing test were used. Thermography was performed in 14 regions of interest (head, neck and thorax) in the following phases: pre-race and +1, +4 and +24 hours of the races. Blood samples were collected in pre-race, immediately after and +1, +4 and +24 hours of the races. Results were submitted to ANOVA and Tukey's test, with p set at 5%. Thermography showed that local temperatures before the race and +24 hours after the races were similar (p > 0.05), as well as between +1 and +4 hours after the races (p > 0.05), which showed higher surface temperatures than the first group (pre-race and +24 hours) (p < 0.05). There was also an increase in red blood cells, hemoglobin and hematocrit immediately after the vaquejada races (p < 0.05) with a return to normality +1 hour after the races. Plasma proteins rose after the runs and How to cite this paper: Silva, C.