Humane killing

Most animals are killed at the end of an experiment, either because their tissues are required as part of the study or because they would otherwise suffer. Methods used to kill animals have the potential to cause pain, suffering and distress, so deciding whether - and how - animals should be killed is an integral aspect of ethical review and a topic that comes within the remit of institutional ethics and animal care and use committees.

There is debate about the `humaneness┬┐ of some commonly used killing techniques, for example exposure to carbon dioxide and some physical methods such as cervical dislocation. Research into the animal welfare implications of different techniques is ongoing, and it is important to ensure that `standard┬┐ techniques and protocols within the establishment are reviewed and refined as necessary to reflect current knowledge.

Regarding individual projects, decisions on the most humane technique for killing animals should be made on a case by case basis, rather than defaulting to routine methods. Factors to take into account include the species, stage of development, size and weight of the animal, the scientific objectives, facilities available and staff competencies. It is important to try to understand the experience of the animal and the associated harms; for example whether they will be moved from their home cage; restrained; exposed to anything they find unpleasant; or experience pain or distress between the application of the technique and death. All of these potential harms should be given due priority when deciding on both killing techniques and the overall justification for projects.