IACUC Policy: Euthanasia    
Policy # IBT-205.00 IACUC Approval: January 27, 2014

The purpose of this document is to define the policy regarding appropriate euthanasia.

This policy applies to all animal care and use subject to oversight by Texas A&M Health Science Center animal facilities and labs.

IACUC must review and approve methods of euthanasia submitted by the Principal Investigator.
Attending Veterinarian (AV) answers questions or concerns about the methods of euthanasia described in this policy.
All Researchers must utilize only the methods of euthanasia approved in their Animal Use Protocol.

AVMA – American Veterinary Medical Association
Euthanasia – “Good Death” in Greek


I.            Categorization of Euthanasia- as outlined in the AVMA Guidelines on Euthanasia. 

    1. Acceptable-Consistently produce a humane death 
    2. Acceptable with conditions-Certain conditions must be met to produce a humane death. Scientific justification is required., including cervical dislocation and decapitation, are used on mice or rats over 10 days of age. 
    3. In all cases, the techniques used must be reviewed and approved by the Institutional Animal Care and Use Committee (IACUC).

II. General considerations

    1. Euthanasia should be performed in procedure rooms or laboratory space away from other mice and rats, when possible. 
    2. Death must be ensured prior to bagging the animal for disposal. 
    3. Personnel performing euthanasia must be properly training in their approved technique to ensure that pain and distress are minimized. 
    4. Chemical methods of euthanasia (CO2 chamber, inhalant anesthetics) must be followed with a physical method (cervical dislocation, bilateral thoracotomy, or exsanguination) to ensure death unless otherwise justified.
    5. Animals should be handled gently as possible prior to euthanasia, and an examination must be performed after euthanasia to confirm the absence of a heartbeat. 
    6. The heart can still beat after breathing has stopped, so simply checking for the cessation of respiration is not adequate.

When animals need to be euthanized by the PAR for humane/veterinary reasons (may or may not be on protocol), animals will be humanely euthanized as per PAR euthanasia policy.

III.            Use of Carbon Dioxide Euthanasia in Rodents

    1. A CO2 chamber is the most commonly used method of euthanasia for small rodents.  COmust originate from a compressed gas cylinder equipped with the appropriate regulator/flowmeter assembly.  CO2 generated from dry ice is not an acceptable method of euthanasia.  The chamber must allow visualization of the mice and rats during euthanasia.  
    1. Proper technique must be followed to ensure a humane death, as CO2 may have noxious properties.  Place the mice or rats into a clean chamber that has not been pre-charged with CO2.  Do not overcrowd the chamber-all mice or rats must be able to make normal postural adjustments.   Rodents from different cages should not be combined in the chamber as this increases distress.  Gradually increase the flow of CO2 into the sealed chamber to minimize distress.  For example, an appropriate flow rate is approximately 20%-30% of the chamber volume per minute.  Leave the mice or rats in the chamber for 4-5 minutes until respiration has ceased.  Remove the mice or rats and confirm the absence of respiration.  A physical method (cervical dislocation, bilateral thoracotomy, and exsanguination) must be used in conjunction with CO2 to ensure death.  

 IV.             Special Considerations for Rodent Fetuses & Neonates

CO2 is not an effective method of euthanasia for rodent fetuses & neonates less than 14days of age.  One of the following methods should be utilized:

    1. Fetuses
      a.Fetuses up to 14 days of gestation: Euthanasia of the dam or removal of the fetus results in rapid fetal death since fetuses cannot survive outside of the uterus
          b.Fetuses from 15 days of gestation to birth: Decapitation with surgical scissors or cervical dislocation are acceptable physical methods. An injection of a chemical anesthetic overdose is an acceptable chemical method.
      2. Neonates 
      a. Neonates up to 10 days of age: Injection of chemical anesthetics, decapitation, and cervical dislocation are acceptable methods of euthanasia. Cervical dislocation or decapitation without anesthesia requires scientific justification, review and approval by the IACUC.
          b. Neonates up to 5 days of age: Hypothermia may be used as a method of anesthesia provided they are not placed directly on the frozen surface (i.e., place them in a latex bag or cloth). 


  1. AVMA Guidelines on Euthanasia. March 2013.
  2. National Research Council. Institute for Laboratory Animal Research. 2011.  Guide for the Care and Use of Laboratory Animals.  Public Health Service, Bethesda, MD.
    1. Public Health Service Policy on Humane Care and Use of Laboratory Animals http://grants.nih.gov/grants/olaw/references/phspol.htm.
    2. Silverman, Jerald, et.al. 2000. The IACUC Handbook: The Basic Unit of an Effective Animal Care and Use Program. Baltimore, MD.
    3. ARENA/OLAW Institutional Animal Care and Use Committee Guidebook, 2nd Ed. 2002.

00- Original version – January 27, 2014