We work hard to minimize iatrogenic effects on deer during capture events. We have many ground capture options (e.g., darting, drop nets, and Clover traps) and helicopter net gunning to safely capture deer. However less is known about how these methods affect stress hormones (cortisol) and indicators of metabolic demand on the animals including serum concentrations of creatinine, blood urea nitrogen, creatine kinase, lactate dehydrogenase, and lactate. Understanding stressors is especially important in an area with high CWD prevalence. During winter of 2023-2024, we captured (ground and helicopter aided) 75 deer in West Tennessee in an area of high CWD to place collars and collect biological samples. We measured cortisol from deer in both years. We measured metabolic indicators in 2024 (mainly helicopter captures). Thirteen deer died within the first 30 days. We tested CWD status on 8 of the mortalities with 4 CWD+ and 4 CWD-. Although small sample size and high variability of the early mortalities with known CWD status, we found a mean cortisol of 6.5 ug/dl for CWD+ (n=3) and 4.4 ug/dl for CWD- (n=3). Cortisol was higher for helicopter captures (5.3 ug/dl, n=42) compared to Clover traps (4.6 ug/dl, n=3), drop nets (3.5 ug/dl, n=11), and darting (2.5 ug/dl, n=3). All physiological measures of metabolism were high for helicopter captures including lactate mean of 30.7 mmol/L. Helicopters with net gunning appeared to be the most stressful physiologically capture method. Stress may be higher in individuals in CWD enzootic areas and be exacerbated by capture events.
