510 ILCS 30/6.2: Entry into State without test.

Except as otherwise provided in this Act, dairy and breeding cattle may enter Illinois without an official test for brucellosis when accompanied by an interstate health certificate approved by the State Animal Health Official of the state of origin and issued by an accredited veterinarian of the state of origin or a veterinarian employed by the Animal and Plant Health Inspection Service of the United States Department of Agriculture, or any successor agency, showing:

1. Such cattle to have originated from a Class Free State or a certified brucellosis-free herd and giving the certified herd number; or

2. Such cattle to be official female brucellosis calfhood vaccinates 24 months of age or under for beef breeds and 20 months of age or under for dairy breeds.