Author ORCID Identifier

Date Available


Year of Publication


Degree Name

Master of Science in Forest and Natural Resource Sciences (MSFNRS)

Document Type

Master's Thesis


Agriculture, Food and Environment


Forestry and Natural Resources

First Advisor

Dr. John J. Cox

Second Advisor

Dr. Matthew T. Springer


Safe and effective chemical immobilization is critical to minimize stress and risk of injury when capturing free-ranging, wild ungulates. Many traditionally favored high potency opioids have been phased out or become unavailable because of increased regulations, leading to the development of two pre-mixed combination drugs, butorphanol-azaperone-medetomidine (BAM) and nalbuphine-medetomidine-azaperone (NalMed-A). Both drugs have been used to chemically immobilize ungulates, but their efficacy has not been documented in elk captured and transported via helicopter. During 2020 – 2022, we chemically immobilized helicopter-captured female elk (Cervus canadensis) with a single IM-injection of BAM (n = 41) or NalMed-A (n = 78) and documented onset of action and physiological responses including heart rate, respiration, body temperature, and blood oxygen saturation. Mean induction times were 8.34 ± 0.03 minutes for BAM and 8.78 ± 0.08 minutes for NalMed-A. We reversed sedation with atipamezole (IM/IV) and naltrexone (IM), with comparable mean reversal times of 4.56 ± 0.09 and 4.14 ± 0.05 minutes for BAM and NalMed-A, respectively. All physiological responses decreased with induction of either drug, whereas post-induction heart rate and respiration were stable.

During these captures, we checked sedated female elk for signs of pregnancy to prepare for a 3-year calf survival study using vaginal implant transmitters to locate newborn calves across Kentucky’s Elk Restoration Zone. During 2020 – 2022, we captured 81 elk neonates and monitored their survival to one year of age or until a mortality occurred, allowing us to estimate elk calf survival for three survival periods (neonatal, summer, and annual), determine cause-specific mortality, and elucidate how maternal characteristics, morphometrics, health metrics, and weather conditions influence survival. Because survival monitoring was not yet completed for calves captured in 2022, we only reported mean survival ranges for calves captured in 2020 and 2021. During these years, we documented 14 mortalities and 6 unknown fates, which were censored. The top proximate cause of mortality was predation or suspect predation by black bears and coyotes (n = 7), followed by trauma (n = 2), and emaciation or abandonment (n = 2). Mean neonatal survival ranged from 0.822 (SE ± 0.057) to 0.844 (SE ± 0.054) and was influenced by total precipitation during the first week of life. Mean summer survival ranged from 0.730 (SE ± 0.067) to 0.772 (SE ± 0.064) and was influenced by total precipitation during the first week of life and femur length. Lastly, mean annual survival ranged from 0.556 (SE ± 0.074) to 0.681 (SE ± 0.071) and was only influenced by femur length. No maternal characteristics and health metrics appeared to influence survival during any period. Although our mean annual survival range is lower than the survival rates previously reported in Kentucky and other eastern elk populations, it is likely more representative of Kentucky’s fully established and stabilized elk herd 20 years after the completion the state’s reintroduction efforts.

Digital Object Identifier (DOI)

Funding Information

This study was supported by several funding sources. Internal sources of funding include the University of Kentucky Appalachian Center Eller & Billings Student Research Award in 2020 and the University of Kentucky College of Agriculture, Food, and the Environment's Karri Casner Environmental Sciences Fellowship in 2020. External sources of funding include the Kentucky Department of Fish and Wildlife Resources (2020 - 2023), the United States Department of Agriculture's McIntire Stennis Cooperative Forestry Research Program (no.: 1007266 and 10219360; 2020 - 2023), and the Rocky Mountain Elk Foundation Project Advisory Committee grant.