The assessment of pain and distress depends on animal observation and professional judgment. Qualified personnel must use subjective measures to determine the presence of pain or distress. Attempts to categorize the intensity of pain or distress as “mild,” “moderate,” or “severe” would require even more subjective measures.

The assessment of pain and distress does not depend on any single indicator. A very broad spectrum of behavioral changes can be related to distress. The Carstens and Moberg (2000) article recently published in ILAR Journal underscores the importance and the diversity of behavioral responses.

We know there are significant differences in pain response between species, between breeds, within strains, and among individual animals. Their response is further modified by the animals' gender, environment, age, nutritional status, and weight. In fact, an infinite combination of factors can influence an animal's pain response. Therefore, it would be impossible to reduce the assessment of pain and distress to a prescribed checklist that would allow us to identify with certainty what is painful or not painful, distressful or not distressful.



Assessment of pain and distress should be a collaborative effort and include the investigator, attending veterinarian, IACUC, and animal care staff. However, the concern for pain and distress should begin at the institutional level. The institutional leadership must establish a culture that demands respect and consideration for laboratory animals. In addition, the institution is responsible for ensuring that the people who work with the animals are qualified. The responsibility for assessing personnel qualifications and training may be delegated to the IACUC or the attending veterinarian, but it is ultimately the institution that must set high standards for personnel qualifications and provide the resources for appropriate training. The institution is also responsible for ensuring that there is adequate veterinary and animal care, that appropriate equipment and facilities are in place, and that a fully functional and qualified IACUC exists.


Investigators have the initial responsibility for assessing the potential for pain and distress in their laboratory animal models. They must consult with their veterinarians if there is the potential for pain and distress, but I advocate that investigators discuss their research protocol with a member of the veterinary staff to ensure that all aspects of the project support optimal animal welfare. Many of

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