Which of the following information need not be present on an official tag?

In the context of animal research and care, compliance with the Animal Welfare Act (AWA) mandates that certain information must be included on official tags associated with animals. Tags are used to identify animals and maintain accurate records pertaining to their care and status.

The information that is typically required on official tags includes identifying numbers for the animal, which help keep track of individual animals in research settings. Additionally, tags often carry the identification of the dealer or source of the animals, which is essential for tracing the origin of laboratory animals and ensuring compliance with regulations.

The inclusion of "USDA" on a tag indicates federal oversight and compliance with the requirements set forth by the United States Department of Agriculture, particularly with regard to the care and treatment of animals used in research. Hence, this detail is significant for regulatory compliance.

On the other hand, the date of birth does not necessarily have to be present on every official tag. While knowing the age of the animal may be important for certain aspects of animal husbandry and research protocols, it is not mandated that this information is included on an official tag. Therefore, this detail can be omitted without violating any regulatory requirements, validating the choice that the date of birth need not be present on an official tag.