The third edition (January 2010) of the Guide for the Care and Use of Agricultural Animals in Research and Teaching (the Ag Guide) was the collaborative effort of a group of 64 authors and provides a science-based reference and performance-based guidelines for institutions that use agricultural species in research and teaching. The adoption of the Ag Guide by the AAALAC Board of Trustees as a primary standard signifies its importance in the AAALAC accreditation process.