Ill. Admin. Code tit. 77, § 996.600
b) Any veterinarian may participate in the program. A veterinarian shall file with the Department an application/agreement to participate on which the veterinarian shall supply a fee schedule listing the fees charged for dog and cat sterilization, examination, and the pre-surgical immunizations specified in the Act and this Part in the normal course of business. The dog or cat sterilization fee may vary with the animal's weight, sex, and species. (Section 30 of the Act)