References

Category B Animals

From USDA AWA Regulations and Standards, Section 2.36 (b)8: 
“(b) The annual report shall:…

State the common names and the numbers of animals being bred, conditioned, or held for use in teaching, testing, experiments, research, or surgery but not yet used for such purposes.”

http://www.access.gpo.gov/nara/cfr/waisidx/9cfr2.html