Policy: The ARC recommends anesthetic overdose or CO2 asphyxiation for euthanasia of mice and rats fifteen (15) days of age and older[1]. When physical methods of euthanasia are used, they must be conducted in accordance with the AVMA Guidelines on Euthanasia and should be performed outside of the housing area. Physical methods of euthanasia must be skillfully executed by well-trained personnel to ensure a quick and humane death. Equipment used for euthanasia must be maintained in good condition.
Decapitation
Decapitation provides a means to recover chemically uncontaminated tissues and body fluids. There is inherent danger in the use of a guillotine and personnel should take adequate precautions for their own safety. The AVMA Guidelines on Euthanasia state that "The equipment used to perform decapitation must be maintained in good working order and serviced on a regular basis to ensure sharpness of blades. The use of plastic cones to restrain animals appears to reduce distress from handling, minimizes the chance of injury to personnel, and improves positioning of the animal" (AVMA Guidelines, p. 45).
Thus, the ARC requires the following[2]: 1) after each day of use, the decapitation equipment should be wiped clean of any biological fluids to prevent buildup of potential corrosion; 2) after cleaning, a few drops of light machine oil (e.g., 3 in 1) should be applied to blade surfaces and blade channels, and the blades run together several times to spread the oil evenly over all moving surfaces; 3) blades should be replaced or sharpened regularly depending upon frequency of use.
Cervical Dislocation
Cervical dislocation induces rapid loss of consciousness and does not chemically contaminate tissue when performed in conscious animals. Consistent with the AVMA Guidelines on Euthanasia, cervical dislocation may not be performed on rodents weighing greater than 200g, since the large physical mass in the cervical region makes manual cervical dislocation physically more difficult. Decapitation may be used if a physical method is required for rodents weighing more than 200g.
Training of Personnel
Personnel responsible for performing euthanasia by physical methods must be properly trained and proficient in carrying out these techniques. Therefore, personnel who will perform decapitation or cervical dislocation without the use of anesthesia must be identified in the approved protocol, and the principal investigator must include a plan for training of personnel who are not experienced in these techniques prior to independently performing euthanasia. Whenever possible, training personnel in physical euthanasia methods should initially include the use of anesthetized animals, or animal carcasses, before practicing on an unanesthetized animal. The DLAM training team (dlamtraining@mednet.ucla.edu) are available for consultation and training in these methods when needed.
Euthanasia of Animals in Housing Rooms
Use of a physical method of euthanasia can be accompanied by ultrasonic vocalizations and pheromones released during handling/restraint prior to euthanasia, and by odors released from the blood after euthanasia, any of which may serve as stress cues to other animals. Therefore, unless it is a health emergency, euthanasia involving a physical method should be performed outside the housing room.
References
Nirah H Shomer, Krystal H Allen-Worthington, Debra L Hickman, Mahesh Jonnalagadda, Joseph T Newsome, Andrea R Slate, Helen Valentine, Angelina M Williams, and Michele Wilkinson. Review of Rodent Euthanasia Methods. J Am Assoc Lab Anim Sci. 2020 May 1;59(3):242-253. doi: 10.30802/AALAS-JAALAS-19-000084. Epub 2020 Mar 5. PMID: 32138808
[2] Records of equipment maintenance should be retained for at least six (6) months and made available for ARC inspection upon request.
Approved 7/26/04; Revised 6/14/10, 11/14/16, 9/9/24
Replaces ARC Policy on Euthanasia of Rodents by Decapitation 9/24/01