Description of box trapping, immobilisation, anaesthesia monitoring and blood chemistry and serology in free-ranging European wildcats (Felis silvestris) in Southwest Germany

Abstract

Specific questions in wildlife research and surveillance require safe and efficient capture, handling and anaesthesia protocols to enable sampling and transmitter placement in free-ranging individuals. For wild felids, various protocols are available, but detailed reports for European wildcats (Felis silvestris) are scarce. In particular, tools for anaesthesia monitoring under field conditions and reference values for heart rate, respiratory rate, oxygen saturation and body temperature are missing. In the present study, European wildcats were caught in box traps before being released into catch bags for manual restraint. Inside the bags, ketamine-xylazine anaesthesia was applied via intramuscular injection, adjusted to the animal’s body weight. During anaesthesia, samples were taken, and vital variables were monitored continuously. Haematology and blood chemistry parameters were obtained, along with serological markers for antibodies against feline immunodeficiency virus (FIV), feline coronavirus and antigens of feline leukaemia virus (FeLV). In total, 29 wildcats were captured, of which 21 were examined and marked with passive integrated transponders. Twelve wildcats were collared with GPS transmitters. Handling time under anaesthesia averaged 30 min (range 26–35 min). Heart rate ranged between 76 and 170 beats/min and respiratory rate between 20 and 52 breaths/min. Relative arterial oxygen saturation stayed mainly between 93 and 99%, and rectal temperature ranged between 36.2 and 40.2 °C. Further, FeLV antibodies were detected in 2/21 samples. The applied protocol facilitated safe and sufficient examination, sampling and transmitter placement, as well as the establishment of haematological and blood chemical values in free-ranging European wildcats for the first time.