510 ILCS 30/6

No dairy or breeding cattle more than 6 months of age shall be imported into the State of Illinois unless they are accompanied by an official interstate health certificate showing the cattle negative to an official test for brucellosis within 30 days prior to the date of entry, except as otherwise provided in this Act. The Department may by regulation impose additional requirements on specific classes of cattle from Class B and Class C states as defined under the Brucellosis Eradication Uniform Methods and Rules approved by the U.S. Department of Agriculture.