MORTALITY, SURVIVAL, AND SEROLOGIC RESULTS FOR ELK (CERVUS CANADENSIS) IN THE CUMBERLAND MOUNTAINS OF TENNESSEE, USA.

Comprehensive disease surveillance has not been conducted in elk (Cervus canadensis) in Tennessee, US, since their reintroduction to the state 20 yr ago. We identified causes of death, estimated annual survival, and identified pathogens of concern in elk at the North Cumberland Wildlife Management Area (NCWMA), Tennessee, US. In 2019 and 2020, we captured 29 elk (21 females, eight males) using chemical immobilization and fitted individuals with GPS collars with mortality sensors. Elk that died between February 2019 and February 2022 were necropsied to identify causes of death; these included disease associated with meningeal worm (Parelaphostrongylus tenuis; n=3), poaching (n=1), vehicular collision (n=1), legal hunter harvest (n=1), and unknown due to carcass degradation (n=3). Using data from GPS collars and known-fate survival models, we estimated an average yearly survival rate of 80.2%, indicating that survival had not significantly increased from soon after elk reintroduction (79.9%). We collected blood, tissue, feces, and ectoparasites opportunistically from anesthetized elk for health surveillance. We identified lone star ticks (Amblyomma americanum; n=53, 85.5%; 95% confidence interval [CI], 73.72-92.75), American dog ticks (Dermacentor variabilis; n=8, 12.9%; 95% CI, 6.13-24.40), and black-legged ticks (Ixodes scapularis; n=1, 1.6%; 95% CI, 0.08-9.83). We detected evidence of exposure to Anaplasma marginale (100%; 95% CI, 84.50-100.00), Leptospira interrogans (70.4%; 95% CI, 49.66-85.50), Toxoplasma gondii (55.6%; 95% CI, 35.64-73.96), epizootic hemorrhagic disease virus (51.9%; 95% CI, 32.35-70.84), and Theileria cervi (25.9%; 95% CI, 11.78-46.59). Johne's disease (Mycobacterium avium subsp. paratuberculosis) is potentially established within the population, but has not been previously documented in eastern elk populations. Disease associated with P. tenuis was a primary cause of death, and more research is needed to understand its ecology and epidemiology. Research to determine population implications of other detected pathogens at the NCWMA is warranted.

EVALUATING THE EFFICACY OF NONINVASIVE FECAL SAMPLING FOR PREGNANCY DETECTION IN ELK (CERVUS CANADENSIS).

Elk (Cervus canadensis) were reintroduced to Tennessee, USA in the early 2000s, with limited reproductive monitoring since initial release. We assessed the efficacy of noninvasive sampling for determining pregnancy using invasive (capture) and noninvasive (fecal collection in the field) techniques at the North Cumberland Wildlife Management Area (NCWMA), Tennessee. We captured 20 female elk 2019-2020, used pregnancy-specific protein B (PSPB) in blood to determine pregnancy and compared results to fecal progesterone metabolite (FPM) concentrations using two commercially available enzyme immunoassay (EIA) kits. Based on PSPB concentrations, 8/11 and 3/4 of captured adult elk (≥2.5 yr of age) were pregnant in 2019 and 2020, respectively; no 1.5-yr-old elk were pregnant (n=5). Using the progesterone EIA kit, FPM concentrations were x̄=192.84±38.63 ng/g (95% CI, 96.48-289.20) for nonpregnant and x̄=536.17±74.98 ng/g (95% CI, 375.97-696.36) for pregnant captured females. For the progesterone metabolite kit, FPM concentrations were x̄=188.16±43.39 ng/g (95% confidence interval [CI], 76.63-299.69) for nonpregnant and x̄=693.52±126.52 ng/g (95% CI, 407.31-979.72) for pregnant captured females. From February to May 2019, we collected 357 fecal samples in 65 areas across 489.62 km2 of the NCWMA. Using extracted DNA and analysis of 15 microsatellites, we identified 62 unique individuals from 128 female fecal samples collected on the landscape. We categorized females from landscape-collected feces as nonpregnant (35.5-40.3%; Metabolite-EIA kits), undetermined (1.6-6.5%; Metabolite-EIA kits), or pregnant (62.9-53.2%; Metabolite-EIA kits) based on a 95% CI of captured female FPM concentrations, giving an overall pregnancy rate of 53.2% using the recommended EIA kit. The pregnancy rate in sexually mature females may be higher, as it was not possible to distinguish age classes of landscape-collected fecal samples; therefore, some may have been from younger age classes not expected to be pregnant. Analysis of FPM may be useful at a population level to detect pregnancy.

Physiologic and blood gas effects of xylazine-ketamine versus xylazine-tiletamine-zolazepam immobilization of white-tailed deer before and after oxygen supplementation: a preliminary study.

OBJECTIVE: To compare oxygenation and ventilation in white-tailed deer (Odocoileus virginianus) anesthetized with two treatments with and without oxygen supplementation. STUDY DESIGN: Randomized, blinded, crossover study. ANIMALS: A total of eight healthy adult white-tailed deer weighing 49-62 kg. METHODS: Each deer was anesthetized twice intramuscularly: 1) treatment XK, xylazine (2 mg kg-1) and ketamine (6 mg kg-1) and 2) treatment XTZ, xylazine (2 mg kg-1) and tiletamine-zolazepam (4 mg kg-1). With the deer in sternal position, arterial and venous blood was collected before and at 30 minutes during administration of oxygen at 1 L minute-1 through a face mask. PaO2 and heart rate (HR) were compared using two-way repeated measures anova. pH, PaCO2 and lactate concentration were analyzed using mixed-effects linear models, p < 0.05. RESULTS: When breathing air, PaO2 was < 80 mmHg (10.7 kPa) in six and seven deer with XK and XTZ, respectively, and of these, PaO2 was < 60 mmHg (8.0 kPa) in three and five deer, respectively. With oxygen supplementation, PaO2 increased to 128 ± 4 and 140 ± 5 mmHg (17.1 ± 0.5 and 18.7 ± 0.7 kPa), mean ± standard error, with XK and XTZ, respectively (p < 0.001). PaO2 was not significantly different between treatments at either time point. HR decreased during oxygen supplementation in both treatments (p < 0.001). Lactate was significantly lower (p = 0.047) with XTZ than with XK (2.2 ± 0.6 versus 3.5 ± 0.6 mmol L-1) and decreased (p < 0.001) with oxygen supplementation (4.1 ± 0.6 versus 1.6 ± 0.6 mmol L-1). PaCO2 increased in XTZ during oxygen breathing. CONCLUSIONS AND CLINICAL RELEVANCE: Treatments XK and XTZ resulted in hypoxemia, which responded to oxygen supplementation. Both treatments are suitable for immobilization of white-tailed deer under the study circumstances.