STANDARD EUTHANASIA GUIDELINES FOR RODENTS
(revised July 2004)

General Considerations:

• Euthanasia techniques must be consistent with the AVMA Guidelines on Euthanasia, June 2007. Methods are chosen to minimize animal pain and distress consistent with needs of the research protocol.



• The method of euthanasia must be specified in the approved Institutional Animal Care and Use (IACUC) protocol. Any chemical euthanasia method must be followed by a physical method from which the animal cannot recover such as decapitation, cervical dislocation, bilateral thoracotomy, tissue perfusion, or dissecting of a major organ



• Use of anesthetic for euthanasia must be an overdose, not an anesthetic dose. Regardless of amount of chemical administered, animal must be completely non-responsive to noxious stimuli (hind paw pinch) before any physical means are applied.



• Sodium pentobarbital and ketamine are controlled substances and must be maintained according to the UCSF Controlled Substances Program



• Physical methods of euthanasia such as decapitation or cervical dislocation of unanesthetized animals require demonstration of competence, and may be approved with proper justification in the IACUC protocol.



• The techniques listed below are suggested common methods for euthanasia of rodents. Other methods outlined in the AVMA Panel on Euthanasia are acceptable with proper justification in the approved IACUC protocol.

Techniques:

Mice > 8 days old

1. Intraperitoneal injection of at least 200 mg/kg sodium pentobarbital euthanasia solution, or other anesthetic at an overdose. Pentobarbital is best diluted to a concentration of no more than 60 mg/ml. Intraperitoneal injection must be followed by cervical dislocation, decapitation, bilateral thoracotomy, or other physical means from which an animal could not recover, after the animal has been determined to be non-responsive to noxious stimuli.



2. Inhalation of CO2 from a pressurized tank in an uncrowded chamber (a standard size mouse cage may contain no more than 5 mice) followed by cervical dislocation, decapitation or bilateral thoracotomy. The regulator for the CO2 tank should be turned no higher than 6 psi. Animals must be left in the chamber for a sufficient time (4 or 5 minutes) so that complete asphyxia has been attained. Whenever possible euthanize mice in their home cage to minimize the stress of being handled and placed into an unfamiliar enclosure.

Mice < 8 days old

1. It is acceptable to place neonates in a CO2 chamber for 4-5 minutes first to anesthetize them, then follow with decapitation. Alternatively, rapid decapitation with sharp scissors may be performed. Remove all other live mice from workspace when performing this procedure.



2. Intraperitoneal injection of at least 200 mg/kg sodium pentobarbital euthanasia solution. Pentobarbital should be diluted to a concentration of no more than 60 mg/ml. After testing for response to painful stimuli, follow with cervical dislocation, decapitation, bilateral thoracotomy, or other physical means from which an animal could not recover.



3. Inhalation of CO2: Place neonates in a single layer in a mouse cage. Place cage in chamber, and fill with CO2 for 4 or 5 minutes. Leave animals in the chamber for at least one half hour. After one half hour, test for response to painful stimuli, then place in a bag and freeze. Note: this procedure may not be done in facilities where a freezer (-10 degrees C) is not available.

Rats and Hamsters

1. Intraperitoneal injection of at least 200 mg/kg sodium pentobarbital euthanasia solution. This is best diluted to a concentration of no more than 60 mg./ml. Intraperitoneal injection must be followed by cervical dislocation, decapitation, bilateral thoracotomy, or other physical means from which an animal could not recover after the animal has been determined to be non-responsive to noxious stimuli.



2. Inhalation of CO2 from a pressurized tank in an uncrowded chamber, followed by cervical dislocation, decapitation or bilateral thoracotomy. The regulator for the CO2 tank should be turned no higher than 6 psi. Animals must be left in the chamber for a sufficient time (4 or 5 minutes) so that complete asphyxia has been attained. Whenever possible euthanize rats and hamsters in their home cage to minimize the stress of being handled and placed into an unfamiliar enclosure.

Guinea pigs

1. Sedate animal (ketamine/xylazine is commonly used). Once deeply sedated (5 - 10 minutes after injection), inject at least 200 mg/kg sodium pentobarbital euthanasia solution intraperitoneally. This must be followed by bilateral thoracotomy or other physical means from which an animal could not recover recover after the animal has been determined to be non-responsive to noxious stimuli.



2. Inhalation of CO2 from a pressurized tank in an uncrowded chamber, followed by cervical dislocation, decapitation or bilateral thoracotomy. The regulator for the CO2 tank should be turned no higher than 6 psi. Animals must be left in the chamber for a sufficient time (4 or 5 minutes) so that complete asphyxia has been attained. Whenever possible euthanize guinea pigs in their home cage to minimize the stress of being handled and placed into an unfamiliar enclosure.

Disposal:

The UCSF Biosafety Committee requires that all animal carcasses, tissues or organs contaminated with infectious agents be discarded in biohazard bags. Due to the difficulty of determining the infective status of most carcasses, the UCSF policy is to treat all carcasses as infected and they must be put in red biohazard bags. The sealed bags must be stored in waterproof containers in designated cold rooms or freezers until removed by the animal waste management contractors. Do not place the red bags in dirty cages being transported to the cage wash facility. Contact the Laboratory Animal Research Center (LARC) at 476-2204 for any information regarding carcass disposal. Training: Only trained individuals should perform euthanasia. Training is provided in individual or group workshops through the IACUC Training and Compliance.