As long as animal research still happens, millions of animals will continue to lose their lives for the purpose of science. Generally, this is planned into experiments before research licences are granted and regulation defines how this can happen. 

Why are animals used in research euthanised? 

Animals are euthanised during experiments for two main reasons: planned and emergency. 

Planned reasons include: 

• Terminating a procedure as part of a humane endpoint 

• Killing surplus animals that aren’t needed or don’t have the ‘right’ characteristics 

• To harvest organs and tissue for ex vivo work, which means research that’s performed on tissue or organs outside the body 

Emergency reasons include: 

• When an animal is in severe pain or distress which can’t be alleviated in another way 

How are animals euthanised in a schedule 1 killing?

Under Schedule 1 methods of killing that are suitable for any animal other than foetal, larval or embryonic forms, meaning any animal that has been born, are outlined under ‘Table A’.

The five methods under Table A are: 

1. Anaesthetic overdose
2. Exposure to carbon dioxide gas in a rising concentration
3. Dislocation of the neck
4. Concussion of the brain by striking the cranium
5. Destruction of the brain by free bullet using an appropriate rifle, gun or ammunition, or captive bolt or electrical stunning followed by destruction of the brain or draining of blood before the return of consciousness

Some of these methods are only suitable for certain animals or weights.

These methods may only be carried out by a registered veterinary surgeon or by a licence holder under the Welfare of Animals at the Time of Killing (England) Regulations 2015, Welfare of Animals at the Time of Killing (Wales) Regulations 2014, or Welfare of Animals at the Time of Killing (Scotland) Regulations 2012.

‘Table B’ outlines the methods of killing that are suitable for foetal, larval, and embryonic forms of animals.

The four methods under Table B are:

1. Anaesthetic overdose
2. Refrigeration, disruption of membranes, maceration, or exposure to carbon dioxide  
3. Cooling of foetuses followed by immersion in cold tissue fixative
4. Decapitation

How is it confirmed an animal has been killed?

To fulfil ‘schedule 1 killing’ requirements, it must be confirmed the animal has been killed using specific methods.

1. Confirmation circulation has stopped permanently, this is usually confirmed by cutting an animal’s femoral artery
2. Destruction of the brain
3. Dislocation of the neck
4. Draining of blood (exsanguination)
5. Confirmation of the onset of rigor mortis
6. Instantaneous destruction of the body in a macerator, although this is uncommon in a research capacity.

What needs to be considered when choosing a method?

Several factors need to be considered when selecting which method under schedule 1 to use, like:

• Scientific outcome. The method chosen must be appropriate for the scientific outcome that is desired. This could include the type of sample that needs to be taken from an animal, what is being measured in terms of data, and how long death will take to occur

• Legislation. This outlines which methods are suitable for which species, weight, and stage of development

Ultimately, the best thing for the animals is not being used in research. Alternatives to animal research ensure a future where no animal suffers for science. 

Where animals are still being used, their welfare must be the priority.