Assessing cervical dislocation as a humane euthanasia method in mice.

Area of Science:

• Veterinary Medicine
• Animal Welfare Science

Background:

• Cervical dislocation (CD) is a common method for mouse euthanasia, approved by the AVMA Panel on Euthanasia in 1972.
• Despite its widespread use, scientific assessments of the humaneness and efficacy of CD have been limited.

Purpose of the Study:

• To compare the efficacy of three cervical dislocation (CD) methods and one thoracic spinal dislocation method in inducing respiratory arrest in anesthetized mice.
• To evaluate the utility of postmortem radiography in assessing the success of euthanasia and identifying spinal lesions.

Main Methods:

• Four spinal dislocation methods were tested on anesthetized mice: three targeting the cervical region and one targeting the thoracic region.
• Euthanasia success was determined by the time to respiratory arrest.
• Postmortem radiography was used to identify spinal lesions in both successfully and unsuccessfully euthanized mice.

Main Results:

• Of 81 mice undergoing CD, 17 (21%) experienced unsuccessful euthanasia, with 5 showing cervical spinal lesions.
• Successful CD euthanasia (64 mice) consistently showed radiographic lesions in the cervical or atlantooccipital region (63/64 mice).
• Thoracic dislocation failed to induce respiratory arrest in all 18 mice tested, and postmortem radiography had minimal promise for quality control.

Conclusions:

• Cervical dislocation (CD) in mice has a significant potential for unsuccessful euthanasia.
• Anesthesia may be beneficial for training and assessing CD techniques.
• Postmortem radiography is not a reliable tool for quality control assessment of CD euthanasia.