Effect of Three Different Sedatives on Electroretinography Recordings in Domestic Pigeons (Columba livia)

Abstract

This study was conducted to compare the effects of 3 different sedative agents on electroretinography (ERG) in domestic pigeons (Columba livia). Six pigeons were sedated with alfaxalone, xylazine, and medetomidine at separate times with a 1-week washout period between sedative administration. After sedation with each agent, pigeons underwent the modified ERG protocol adapted from the standardized protocol for dogs. The scotopic mixed rod and cone response was recorded after 20 minutes of dark adaptation, and the photopic cone response and photopic flicker response were recorded after 10 minutes of light adaptation. Either a 1-way analysis of variance or a Kruskall-Wallis test was used to compare the a-wave and b-wave implicit time and amplitude. No significant differences were observed in the scotopic mixed rod and cone response among all 3 sedatives used. Compared with alfaxalone, medetomidine significantly prolonged the a-wave implicit time, depressed the b-wave amplitude of photopic cone response, and prolonged the peak implicit time of the photopic flicker response (P < .05). These results show that medetomidine has a depressant effect on photopic ERG in pigeons at a dosage that produces light sedation.