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Institutional Animal Care and Use Committee

Guideline #5

Tail Clipping

Tail clipping of mice and rats is often used to obtain tissue samples for analysis.

Tail clipping of mice or rats without anesthesia (local or general) may be performed only once on an animal and only up to the time of weaning (21 days of age). For this procedure, only 1-2 mm of tissue can be removed each time. This procedure is a KSU pain or distress category C.

Anesthesia is required for the animal in the following situations:

  • Animals older than 21 days of age
  • If a repeated sample is needed: the sum total of tissue removed cannot exceed 5 mm of tail tissue
  • If greater than 5 mm of tissue is required: post procedural analgesia is required unless adequate scientific justification for no analgesia is provided by the investigator and approved by the IACUC. This is considered a KSU pain or distress category D (alleviated pain and distress)
  • Anesthesia can be in the form of a topical anesthetic such as lidocaine/prilocaine cream or general anesthesia can be utilized.

In all cases, bleeding must be controlled.

Tissue obtained from ear punching as a form of identification can also be used for analysis.

If you have any questions about this process, please contact the Comparative Medicine Group (CMG) at 532-5640.

Any deviations from the guideline concerning tail clipping will be considered and reviewed by the IACUC on a case by case basis.