Health management during prolonged confinement in wood bison (Bison bison athabascae): a veterinary perspective

The Alaska Department of Fish and Game maintained an increasing herd of endangered wood bison (Bison bison athabascae) captive for 4 years longer than the anticipated 2 year quarantine after importation of 53 juveniles from... [ view full abstract ]

The Alaska Department of Fish and Game maintained an increasing herd of endangered wood bison (Bison bison athabascae) captive for 4 years longer than the anticipated 2 year quarantine after importation of 53 juveniles from Canada. Although the animals were obtained from a specific pathogen-free herd, the initial quarantine testing and pathogen screening focused on regulatory diseases and known pathogens such as Johnes disease, Tuberculosis, Brucellosis and Bovine Respiratory Disease complex. Parasitic treatments were comprehensive. However, during the prolonged confinement in a public zoological park, unanticipated husbandry, medical, nutritional, trace mineral deficiencies and parasitic disease issues arose. In response to routine health monitoring and disease surveillance, management and veterinary treatment protocols were developed and constantly evolving in consultation with international bison experts. Adaptive management strategies were tested and instituted to successfully resolve each issue identified. Tranquillization, anesthetic and handling protocols were developed to reduce stress and injuries. Successes included a treatment of anemic calves and yearlings (n=19) in poor body condition to improve health especially vitamin and trace mineral balance. Prior to treatment the mean blood selenium (0.122 ppm) was at the lower limits of the normal range for cattle. After treatment, blood selenium, serum iron and copper increased significantly. Most importantly, mean body condition scores increased by 4% in this cohort indicating a positive response to the treatment regime. Herd health continued to improve over 12 months and blood cell indices were within the normal range prior to release. Cohorts of bison including adults were successfully treated for vitamin, selenium and copper deficiencies, grain overload, verminous gastritis, weak calf syndrome and low pregnancy rates. In March 2015, 100 healthy bison of all age classes with high BC scores were transported via cargo air craft for a soft release/reintroduction to Alaska, 200 years since the species last roamed the state.