Immobilization and Anaesthesia in Asiatic Lions (<i>Panthera</i> <i>leo</i> <i>persica</i>)

Abstract | A total of 12 trials were conducted in 8 Asiatic and hybrid lions (Panthera leo persica) for diagnostic and surgical procedures. All the lions were immobilized with a combination of xylazine and ketamine at the rate of 1.00 mg/kg and 2.00 mg/kg body weight, respectively, using darts based on assumed body weight. Ketamine and propofol intravenously were used as induction agents sufficiently to achieve deep plane of anaesthesia and good jaw muscle relaxation in six trials each of treatment I and II. The commercially available large animal endotracheal tubes and custom made silicon medical grade tubes were used for intubation either by direct visualization or by digital palpation of glottis. Anaesthesia was maintained with isoflurane. The study revealed that the young lions required 1.08±0.10 and 2.70±0.26 mg/kg and adult required 1.06±0.30 and 2.64±0.08 mg/kg body weight of xylazine and ketamine, respectively for immobilization. Ear flick reflex was taken as an indicator for safe and appropriate time for approaching the lion after immobilization, which was completely abolished only after 1.37 and 2.01 minutes after recumbency in young and adult lions, respectively. Based on the radiographic distance between snout and distal larynx endotracheal tubes of one meter length and 30 mm diameter were suitable for intubation and the larynx was located between 5th and 6th cervical vertebrae. The dose of ketamine and propofol required for induction was 1.00 mg/kg and 1.92 mg/kg body weight, respectively, in immobilized lions and intubation could be safely performed under propofol induction by oropharyngeal digital palpation of glottis for administration of inhalant anaesthetics. Both ketamine and propofol could be used as induction agents in lions immobilized with xylazine-ketamine and for further maintenance with isoflurane.

Keywords | Asiatic lions, Anaesthesia, Ear flick reflex, Intubation, Xylazine, Ketamine, Propofol