Euthanasia of Rodent Fetuses and Neonates

BACKGROUND

The AVMA Guidelines for the Euthanasia of Animal: 2013 Edition (p. 50) provides recommendations for the euthanasia of prenatal or neonatal animals. PHS Policy on Humane Care and Use of Laboratory Animals requires IACUCs to use the recommendations of the AVMA Guidelines on Euthanasia.

Rodent fetuses along with other mammals are unconscious in utero and hypoxia dose not evoke a response. Therefore, it is unnecessary to remove fetuses for euthanasia after the dam is euthanized.

IACUC Guidelines for Rodents

Mouse and rat: Fetus     < 15 days gestation

Guinea pig: Fetus < 35 days gestation                          

Euthanasia of the dam or removal of the fetus results in rapid death of the fetus.

Mouse and rat: Fetus ≥ 15 days gestation

Guinea pig: Fetus ≥ 35 days gestation

1.  Euthanize the dam, then remove the entire uterus or pups with amniotic sac intact. The immediate cessation of uterine blood flow and oxygen delivery to the fetus results in rapid death. Fetuses must be removed from the uterus/amniotic sac to verify death.

2.  If fetuses are removed from the uterus and begin to breathe, additional steps must be taken to euthanize each fetus.

  • Intraperitoneal injection of euthanasia solution or chemical anesthetic agent(euthanasia dose is three times the anesthetic dose)
  • Decapitation - Cervical dislocation
  • Anesthesia* followed by chemical fixation or rapid freezing in liquid nitrogen

Mouse and rat: Neonate < 10 day

  • Intraperitoneal injection of euthanasia solution or chemical anesthetic agent (euthanasia dose is three times the anesthetic dose)
  • Decapitation
  • Cervical dislocation
  • Anesthesia* followed by chemical fixation or rapid freezing in liquid nitrogen

Mouse and rat: Neonate ≥ 10 days

Guinea pig: Neonate (all ages)

Follow guidelines for adults.

*Anesthesia may be achieved by an injectable agent or isoflurane; alternatively, hypothermia may be used in pups < 6 days of age if adequately justified.

The Guide for the Care and Use of Laboratory Animals (the Guide, NRC 2011) states: "because neonatal rodents are resistant to the hypoxia-inducing effects of CO2 and require longer exposure times to the agent alternative methods should be considered (e.g., injection with chemical agents, cervical dislocation, or decapitation)." (p. 124)

In all cases, the person performing the euthanasia must be fully trained in the appropriate procedures.

For other species, please contact a veterinarian.

PUBLIC STATEMENTS: Report of the ACLAM Task Force on Rodent Euthanasia, 2005 (p. 2-3)

NIH Office of Animal Care and Use Animal Research Advisory Committee. Guidelines for the Euthanasia of Rodent Feti and Neonates, Revised 6/22/16.

 

Approved: May 2005

Revisions Approved: 8/2008, 12/2012, 4/2013, 5/2018