Butorphanol–azaperone–medetomidine and ketamine–butorphanol–azaperone–medetomidine chemical immobilization in habituated subadult female giraffe (Giraffa camelopardalis)

Objective

To describe the effects of butorphanol–azaperone–medetomidine (BAM) and ketamine–butorphanol–azaperone–medetomidine (KBAM) used for the chemical immobilization of giraffes.

Study design

Quasi-experimental trial.

Animals

A group of 10 habituated subadult female giraffes.

Methods

Five giraffe were immobilized with BAM (0.02 mL cm^–1 estimated shoulder height) and five with KBAM (0.015 mL cm^–1 estimated shoulder height BAM and 200 mg ketamine). Time to events were recorded (time to recumbency and recovery time). Physiological variables (heart rate, respiratory rate, rectal temperature, invasive arterial blood pressure and peripheral oxyhaemoglobin saturation) were recorded every 5 minutes and arterial blood gas analysis was performed every 10 minutes after instrumentation. Atipamezole (5 mg mg^–1 medetomidine administered) and naltrexone (1 mg mg^–1 butorphanol administered) were administered intramuscularly at 30 minutes post-recumbency for recovery. Time to events, physiological and arterial blood gas data were compared between drug combinations using a two-sample t-test (significance was p < 0.05). Data are shown as mean ± standard deviations.

Results

All giraffes were successfully immobilized. Based on measured shoulder height, the doses administered were 0.70 and 0.48 mg cm^–1 for butorphanol, 0.28 and 0.2 mg cm^–1 for azaperone and medetomidine in BAM and KBAM, respectively. Times to recumbency were 17.1 ± 9.3 and 6.3 ± 1.1 minutes for BAM and KBAM respectively (p = 0.06). All giraffes had hypoxaemia and hyperlactataemia, with PaO₂ values of 52 ± 13 and 41 ± 4 mmHg and lactate values of 14.4 ± 6.1 and 11.0 ± 5.5 mmol L^–1 for BAM and KBAM, respectively. Recoveries were calm with minimal ataxia.

Conclusion and clinical relevance

BAM and KBAM produced reliable chemical immobilization for 30 minutes. The addition of ketamine to the BAM combination is recommended because of its faster induction time. Because of clinically significant hypoxaemia, oxygen supplementation should be administered if these drug combinations are used.