Development of a practice guideline for general anaesthesia of free-living small mammals in compliance with animal welfare standards

Small mammals are important species in the context of landscape conservation. Many small mammal species are endangered due to the severe changes our landscape has undergone for many decades. Live capture of these small mammals may be necessary to provide the information and insight needed for species conservation.


Sampling small mammals in the field was challenging from an animal welfare perspective. To reduce fear, pain, and stress, a brief period of general anesthesia may be appropriate to maintain animal welfare, depending on the manipulation planned. Ether, historically used for general anesthesia, was no longer permissible due to its severe irritation of mucous membranes, and field-tested, welfare-compliant alternatives were lacking. For this reason, the Institute of Fish and Wildlife Health (FIWI) is developing alternative, animal welfare-compliant protocols and material recommendations for inhalation anesthesia in free-living small mammals under field conditions. Using a new, customized mobile isoflurane anesthesia machine, the FIWI veterinary team was in the field this summer performing the first isoflurane anesthesia of free-living mice. In collaboration with biologists from the Zurich University of Applied Sciences (ZHAW) and the Solothurn Museum of Nature, various long-tailed mice, voles and shrews were successfully captured and anesthetized. Now the collected data will be evaluated. The project is funded by the Eva Husi Foundation for Animal Welfare.

Contact: Iris Marti, Mirjam Pewsner