Comparative investigations on inhalation anaesthesia with isoflurane (Forene®) and sevoflurane (SEVOrane®) in racing pigeons (Columba livia Gmel., 1789, var. domestica) and presentation of a reference anaesthesia protocol for birds

A conventional inhalation anaesthesia using an isoflurane and sevoflurane-oxygen-nitrous oxide-mixture was performed in each six domestic pigeons (Columba livia Gmel., 1789, var. domestica). Over a period of 60 minutes routine anaesthetic monitoring including reflex score (12 reflexes, cloacal body temperature and pulse oximetry) was performed. For anaesthesia maintainance 4.0 +/- 0.3 Vol. % sevoflurane compared to 2.0 +/- 0.2 Vol. % isoflurane were used. The induction period using sevoflurane was shorter (95 +/- 9 sec) than by using isoflurane (154 +/-2 sec). The recovery period was significantly shortened using sevoflurane (162 +/- 12 sec) compared to isoflurane with 186 +/- 12 sec. Results show, that the use of sevoflurane is indicated especially in patients hearing anaesthesia risks, but has a number of advantages, though anaesthetic potency is approximately 50% lower than in isoflurane, causing higher costs. Furthermore low toxicity of sevoflurane leads to a lower burden for the surgical staff through socalled >>waste gases<<, which play an important role in avian anaesthesia using a head chamber for application. Beside a review on current techniques in avian anaesthesia this paper includes a standardised detailed anaesthesia protocol description of avian inhalation anaesthesia regarding the technical equipment as well as its practica, which allows an exact documentation of the anaesthetic, meeting legal requirements, too. The results show that inhalation anaesthesia with isoflurane or sevoflurane has to be preferred even in birds when compared to ketamine anaesthesia, the future use of which has to be restricted to sedation and immobilisation partly due to animal welfare grounds.