Effect of Intranasal Midazolam-Butorphanol Premedication on Sevoflurane Anaesthesia in Traumatised Buzzards (Buteo...

Stress management is vital for safe avian anaesthesia. Intranasal (IN) midazolam-butorphanol may reduce handling stress and anaesthetic requirements in buzzards (Buteo spp.) OBJECTIVES: To evaluate the clinical efficacy and cardiopulmonary effects of IN midazolam-butorphanol premedication compared to mask induction with sevoflurane in buzzards.

Sixteen juvenile buzzards of undetermined sex were randomly allocated into two equal groups. The experimental group received IN midazolam (2 mg/kg) and butorphanol (1 mg/kg). The control group received sevoflurane mask induction without premedication. Heart rate (HR), respiratory rate (f_R), ECG, SpO₂, Pe'CO₂, body temperature and sevoflurane vaporiser setting (SVS) were monitored at 0, 5, 15, 30 and 60 min. Aortic peak velocity (APV) was measured via echocardiography. Data (mean ± SD) were compared using Student's t-test, and repeated-measures ANOVA (p < 0.05).

Statistical analysis revealed no significant differences between groups regarding peri-anaesthetic, f_R, body temperature, Pe'CO₂ and APV. However, SpO₂ was significantly higher in the premedicated group at 15 min (p = 0.045). Notably, the premedicated group required significantly lower SVS at 0 and 5 min compared to the control group (p = 0.001). Repeated-measures analysis indicated significant differences in SVS (p = 0.042) and HR (p = 0.033) with the control group showing higher SVS and lower HR; regarding ECG parameters, both QT (p = 0.001) and ST intervals (p = 0.011) were significantly prolonged in the control group. All physiological variables remained within acceptable limits, and all birds recovered uneventfully from anaesthesia.

The IN midazolam-butorphanol provided superior induction quality, significantly reduced inhalant anaesthetic requirements and maintained stable cardiopulmonary function. This protocol is a practical alternative for the anaesthetic management of traumatised buzzards.