As a reactive species, the red deer is sensitive to both negative exogenous and endoge-
nous stimuli. An intensive hunting period may have a particularly negative impact on game ani-
mals. The aim of this study was to determine the plasma cortisol level and biochemical parameters
in 25 wild red deer (Cervus elaphus) harvested during stalking hunts in correlation with the sex and
age of the animals. The mean cortisol concentrations in the stags and hinds analyzed in this study
were similar (20.2 and 21.5 ng/mL, respectively). Higher HDL cholesterol values were found in the
blood of the hinds than in stags (p < 0.05). Similarly, the mean levels of LDL cholesterol, lactate
dehydrogenase, and alanine aminotransferase were higher by 21%, 16%, and 42%, respectively, in
the blood of the hinds. In contrast, the levels of alkaline phosphatase, bilirubin, and aspartate
aminotransferase were higher in the stags (by 30%, 49%, and 36%, respectively). There was a neg-
ative correlation of the cortisol concentration with urea and bilirubin and a positive correlation
between cortisol and aspartate aminotransferase in the stags (p < 0.05). In turn, a negative correla-
tion was found between the cortisol and urea levels in the hinds (p < 0.05). In summary, the stress
caused by stalking hunts and the characteristic behavior of red deer during the mating season had
an impact on chosen biochemical parameters. The increased concentration of cortisol resulted in a
decrease in the carcass mass, which may lead to the deterioration of the physical condition of
animals on hunting grounds.