Chemical Restraint in Southern Tiger Cats (<i>Leopardus guttulus</i>) with Methadone or Morphine Associated with Xylazine-Ketamine

Abstract The Southern Tiger Cat ( Leopardus guttulus ) is an endangered species, requiring effective anesthesia for clinical procedures, yet species-specific studies are lacking. This study aims to assess and compare the effectiveness of methadone or morphine combined with xylazine-ketamine for the immobilization of Southern Tiger Cats ( Leopardus guttulus ). The animals were randomly allocated to receive sedation with methadone (0.3 mg kg) or with morphine (0.5 mg kg) in association with xylazine-ketamine (1.0 mg kg and 10.0 mg kg, respectively) intramuscularly. Electrocardiography parameters and physiological variables were recorded every five minutes since the application. After 40 minutes of assessment, reversal protocol for opioids and α2-adrenergic agonist was applied using naloxone and yohimbine, and the quality of recuperation was evaluated. In this study, no significant differences were noted between groups or assessment times in the physiological variables monitored. One subject, presented idioventricular accelerated rhythm, attributed to morphine administration and confirmed by its reversal. Recovery evaluation demonstrated favorable outcomes, although some animals presented adverse effects, exacerbated by supplementary ketamine doses. The morphine-xylazineketamine and methadone-xylazine-ketamine protocols demonstrated similar efficacy in Southern Tiger Cats ( Leopardus guttulus ), exhibiting stable physiological parameters and smooth recovery. The use of antagonists facilitated uneventful recovery, contributing valuable insights into anesthetic protocols for endangered species. The applied protocols provided safe examination and valuable insights into anesthetic protocols for this endangered species.