Immobilization, cardiopulmonary and blood gas effects of ketamine-butorphanol-medetomidine versus butorphanol-midazolam-medetomidine in free-ranging serval (Leptailurus serval).

Abstract Objective To compare ketamine–butorphanol–medetomidine (KBM) with butorphanol–midazolam–medetomidine (BMM) immobilization of serval. Study design Blinded, randomized trial. Animals A total of 23 captures [KBM: five females, six males; 10.7 kg (mean); BMM: 10 females, two males; 9.6 kg]. Methods Serval were cage trapped and immobilized using the assigned drug combination delivered via a blow dart into gluteal muscles. Prior to darting, a stress score was assigned (0: calm; to 3: markedly stressed). Drug combinations were dosed based on estimated body weights: 8.0, 0.4 and 0.08 mg kg–1 for KBM and 0.4, 0.3 and 0.08 mg kg–1 for BMM, respectively. Time to first handling, duration of anaesthesia and recovery times were recorded. Physiological variables including blood glucose and body temperature were recorded at 5 minute intervals. Atipamezole (5 mg mg–1 medetomidine) and naltrexone (2 mg mg–1 butorphanol) were administered intramuscularly prior to recovery. Data, presented as mean values, were analysed using general linear mixed model and Spearman’s correlation (stress score, glucose, temperature); significance was p Results Doses based on actual body weights were 8.7, 0.4 and 0.09 mg kg–1 for KBM and 0.5, 0.4 and 0.09 mg kg–1 for BMM, respectively. Time to first handling was 10.2 and 13.3 minutes for KBM and BMM, respectively (p = 0.033). Both combinations provided cardiovascular stability during anaesthesia that lasted a minimum of 35 minutes. Recovery was rapid and calm overall, but ataxia was noted in KBM. Stress score was strongly correlated to blood glucose (r2 = 0.788; p = 0.001) and temperature (r2 = 0.634; p = 0.015). Conclusions and clinical relevance Both combinations produced similar effective immobilization that was cardiovascularly stable in serval. Overall, BMM is recommended because it is fully antagonizable. A calm, quiet environment before drug administration is essential to avoid capture-induced hyperglycaemia and hyperthermia.