Complication with re-sedation in southern Ground-hornbills (Bucorvus leadbeateri) following partial reversal of two orally administered sedation protocols

The combination of midazolam, medetomidine and azaperone (MMA) was compared with the combination of butorphanol, azaperone and medetomidine (BAM) for the sedation of southern Ground-hornbills when administered orally in a bait. The BAM combination (30 mg butorphanol, 12 mg azaperone and 12 mg medetomidine per ml of solution) at a dose of 0.14 ml/kg was the only combination that did not result in re-sedation after reversal. However, induction of sedation was long, and sedation was only deep enough for capture, handling, and minor, non-invasive procedures. The MMA combination and higher doses of the BAM combination resulted in quicker inductions although individuals showed mild to severe signs of re-sedation, starting at 4 hours after reversal and continuing for as long as 17 hours after reversal. Care should therefore be taken when administering these combinations orally to southern Ground-hornbills as it appears that absorption, metabolism and excretion are unpredictable in this species.