510 ILCS 30/6.7
Bison, except steers, spayed heifers, or calves under 6 months of age, may be imported into Illinois if consigned direct for immediate slaughter to an approved slaughtering establishment and accompanied by a consignment certificate, or if accompanied by an official health certificate indicating the bison:
(c) Were negative to an official brucellosis test within 30 days prior to importation.
Bison steers, spayed heifers, or calves under 6 months of age may enter Illinois when accompanied by an official health certificate, or consigned for immediate slaughter to an approved slaughtering establishment accompanied by a consignment certificate.
(from Ch. 8, par. 139.7)
(Source: P.A. 78-818.)