Avian Sedation

COMPARISON OF THREE MIDAZOLAM-BASED SEDATION PROTOCOLS IN BUDGERIGARS (MELOPSITTACUS UNDULATUS) AND BLACK-CHEEKED LOVEBIRDS (AGAPORNIS NIGRIGENIS)

This randomized, crossover study evaluated three sedation protocols administered subcutaneously in nine budgerigars (Melopsittacus undulatus) and nine black-cheeked lovebirds (Agapornis nigrigenis). All protocols included midazolam (5 mg/kg), combined with butorphanol (5 mg/kg) (BM), medetomidine (20 lg/kg) (MM), or alfaxalone (13 mg/kg) (AM). Mortalities from suspected cardiorespiratory arrest were observed when AM was used in lovebirds, even after reduction of alfaxalone dosage to 3 mg/kg, and therefore this protocol was excluded from further use in this species. Induction and recovery times were recorded and their quality assessed. Sedation depth and heart and respiratory rates were measured every 5 min and radiographic positioning was attempted at 10 and 20 min. At 30 min, midazolam and medetomidine were reversed with flumazenil (0.05 mg/kg, SC), and atipamezole (0.2 mg/kg, SC), respectively. MM consistently provided deep sedation in both species, with successful radiographic positioning at every attempt. As expected, heart rate was often lower with MM than with other protocols, but no associated complications were noted. In budgerigars, BM had the lowest radiographic positioning success rate (10 min: 5/9, 20 min: 3/9), whereas in lovebirds it provided significantly deeper sedation (P < 0.001), allowing radiographic positioning in all subjects. In both species, BM provided the shortest recovery times. AM resulted in reliable radiographic positioning of all budgerigars at 10 min, but not at 20 min (5/ 9), and provided consistently poor recoveries. This study highlights how differently two psittacine species of similar size may react to the same sedation protocols. AM sedation cannot be fully reversed and produced significant undesirable effects, several of which have been previously reported with alfaxalone administration to avian species. The authors therefore caution against using alfaxalone-midazolam combinations in budgerigars and black-cheeked lovebirds. Both BM and MM provided reliable sedation in these species, and appear to be suitable alternatives to AM.

Sedation of Wild Pyrenean Capercaillie (Tetrao urogallus aquitanicus) Using Intramuscular Midazolam

Global Positioning System (GPS) tracking offers key information in the study of movement ecology of threatened species. Nevertheless, the placement of GPS devices requires animal capture and handling, which may represent a challenge to the individual’s survival after release, mainly due to capture myopathy. The Pyrenean Capercaillie (Tetrao urogallus aquitanicus) is a threatened galliform especially sensitive to handling, extremely elusive, and challenging to capture. Our goal was to adapt a sedation protocol for Pyrenean Capercaillies undergoing GPS tagging, in order to increase their welfare and safety during the procedure. From 2018 to 2021, 23 wild Pyrenean Capercaillies were captured and sedated for GPS tagging as part of a European conservation project of emblematic Pyrenean avian species. The birds received intramuscular (IM) sedation with midazolam (ranging from 1.9 mg/kg to 8.08 mg/kg) and were handled for 20 to 40 min. Sedation was reversed with flumazenil (0.1 mg/mL IM). The sedated capercaillies were less responsive to stimuli (i.e., closed eyes and recumbency), showing discrete to no response to handling (i.e., placement of the GPS device, physical examination, cloacal temperature measurement, or reflex tests). Such response was compared in birds with sedation doses above and below the average dose (5.17 mg/kg). Only one clinical sign showed statistically significant differences between the two groups (“open-mouth breathing” sign, p = 0.02). A mortality rate of 4.35% was registered (one individual died during handling). Sedation facilitated the handling of the birds and faster interventions in the field, without increasing mortality when compared to handling without sedation. Therefore, sedation was shown to be a useful tool to reduce stress related to capture and handling of the threatened Pyrenean Capercaillie.

Evaluation of dexmedetomidine-midazolam sedation in budgerigars (Melopsittacus undulatus)

OBJECTIVE

To evaluate the sedative effects of IM administration of a high or low dose of dexmedetomidine in combination with midazolam in budgerigars (Melopsittacus undulatus).

ANIMALS

20 healthy adult budgerigars.

PROCEDURES

In a prospective, randomized, blinded study, birds were sedated with a high dose (HD; 0.04 mg/kg, IM; n = 10) or low dose (LD; 0.01 mg/kg, IM; 10) of dexmedetomidine in combination with midazolam (3 mg/kg, IM). Twenty minutes later, atipamezole (0.4 mg/kg [HD group] or 0.1 mg/kg [LD group], IM) and flumazenil (0.1 mg/kg, IM) were administered for reversal of sedation.

RESULTS

Times to first effect and to sternal recumbency after administration of the sedatives and times to standing and eating after administration of the antagonists did not differ between groups. Most birds (9/10 in the HD group and 7/10 in the LD group) lost the righting response by 10 minutes after sedative administration, and the peak effect for radiographic positioning was by 15 minutes. Although it was not clinically relevant, most birds showed mild resedation by 60 minutes after administration of the reversal agents. There was no significant cardiorespiratory compromise detected with either protocol.

CLINICAL RELEVANCE

Dexmedetomidine-midazolam can safely and effectively provide a dose-dependent level of sedation in healthy budgerigars. The HD protocol is recommended for radiographic positioning, as it allows for a more reliable, deeper plane of sedation.