Which of the following roles is NOT specified by USDA AWAR?

The role of Senior Researcher is not explicitly defined by the USDA Animal Welfare Act Regulations (AWAR). In contrast, the other roles mentioned are clearly outlined within the regulations governing animal care and use.

The Institutional Official is responsible for ensuring that the institution complies with all applicable laws and regulations, indicating the highest level of institutional oversight. The Attending Veterinarian plays a critical role in ensuring the health and welfare of laboratory animals, providing expertise on veterinary care, and overseeing animal care personnel. The Nonaffiliated Member serves on the Institutional Animal Care and Use Committee (IACUC) to provide an outside perspective, ensuring that the welfare of animals is considered from a broader community viewpoint.

While researchers and their roles are integral to the animal research process, the USDA AWAR does not specify a "Senior Researcher" as a defined role within its framework, which makes this option the correct choice for the question. Understanding these definitions is crucial for maintaining compliance with animal welfare standards and ensuring responsible research practices.