Chemical Immobilization in Captive Large Felids: A Retrospective Clinical Study

Large felids are animals of considerable ecological, scientific, and conservation interest, characterized by complex behaviors, vulnerability to anthropogenic pressures, and specific management requirements both in natural habitats and controlled environments. Despite their importance, the scientific literature on the pharmacological restraint of these species remains limited. This retrospective study involved the creation of a structured and comprehensive dataset to organize information collected from clinical cases managed by the Veterinary Anesthesiology team of the University of Padua between 2016 and 2024, with the objective of analyzing the pharmacological immobilization techniques employed. Over the study period, 84 clinical cases were evaluated, involving 60 large felids: 6 pumas (Puma concolor), 12 lions (Panthera leo), 17 leopards (Panthera pardus), and 25 tigers (Panthera tigris). Of these, 67 cases required pharmacological immobilization for medical or surgical procedures, distributed as follows: 8 pumas, 15 lions, 18 leopards, and 26 tigers. The animals’ ages, the reasons for pharmacological immobilization, and the anesthetic protocols employed were analyzed. A total of 11 anesthetic protocols were used, with the dexmedetomidine–ketamine–midazolam combination (Protocol 1, PRT1) applied in 34 cases and the dexmedetomidine–ketamine–midazolam–butorphanol combination (Protocol 2, PRT2) applied in 10 cases. Specific time points were identified to standardize anesthetic records, with particular focus on key phases such as induction, maintenance, and recovery. Qualitative evaluations reported in the anesthetic records, namely immobilization score, reaction to manipulation, and quality of induction, were also considered. From PRT1, 10 cases were designated as PRT1-P (Protocol 1–Propofol), in which propofol was the sole supplemental anesthetic administered during maintenance. For PRT1, PRT1-P, and PRT2, physiological parameters were analyzed between 40 and 90 minutes after the administration of the first induction drugs. The recovery phase was assessed only in PRT1-P, due to heterogeneity in anesthesia management across the other groups. All protocols provided reliable pharmacological immobilization, ensuring the safety of both animals and operators. In particular, PRT1, PRT1-P, and PRT2 allowed the maintenance of adequate anesthetic depth while keeping physiological parameters within satisfactory ranges, even during medium- to long-duration procedures.