Low dose ketamine-xylazine protocol for immobilization of problematic wild rhesus macaques (Macaca mulatta)

Rhesus macaques, known for their adaptability and proximity to human settlements, often pose challenges when their behaviour becomes problematic or pose a threat to both the environment and human population. Chemical immobilization of problematic rhesus macaques has emerged as an approach to mitigate these challenges. This study investigated the use of ketamine (a dissociative anaesthetic) 5 mg/kg body wt combined with xylazine (α₂-adrenoreceptor agonist) 2 mg/kg body wt in achieving temporary immobilization for the capture of problematic rhesus macaques and then transport them to a safe and natural habitat. The anaesthetic combination was delivered intramuscularly through a dart with the mean induction time of 3.56±0.15 min. Different physiological variables were recorded at different time intervals once the animals were safe to handle. It was found that this combination provided 86.21±1.63 (mean±SE) min window of anaesthesia and analgesia with a mean recovery period of 30.19±1.67 min that provided sufficient time to translocate problematic rhesus macaque.