Toe-clipping (removal of the first bone of certain toes, corresponding to a predetermined numbering code), as a method of identification of small rodents, should be used only when no other individual identification method is feasible and should be performed only on neonatal mice up to 7 days of age, consistent with the “Guide for the Care and Use of Laboratory Animals” (8th edition, 2011). 
Toe clipping can be considered under the following conditions:

  1. This method should only be used when no other less invasive method is available. All available alternative methods of identification must first be considered.
  2. A written explanation of why it is necessary is required, including a discussion of why alternate methods are unsatisfactory. This will be considered and must be approved by the IACUC.
  3. It should only be performed on neonatal mice up to 7 days of age and the minimum number of toes should be clipped. Under all circumstances, aseptic technique should be followed. Use of anesthesia or analgesia should be commensurate with the age of the animals.
  4. The Attending Veterinarian should review the technique/procedure.

IACUC approved: July 2011