The Commissioner of Agriculture shall supervise commission sales stables where equines are sold at public auctions. Any person, firm or corporation engaged in the business of selling equines at auctions shall annually apply to the commissioner for a license upon a form to be prescribed by the commissioner. The fee for a license to hold one public auction annually shall be thirty dollars and the fee for a license to hold more than one public auction annually shall be one hundred dollars. Each such license shall be issued for the period of one year from July first and may be revoked for cause. If, in the judgment of the commissioner, any provision of this section has been violated, the commissioner shall send notice by registered or certified mail to the licensee, who shall be given a hearing, and, if violation is proven, the licensee’s license shall be revoked. All stables and sales rings shall be kept clean and shall be suitably disinfected prior to each sale. The provisions of this section shall not apply to the private sale of equines conducted by the owner thereof. Any person, or any officer or agent of any corporation, who violates any provision of this section or who obstructs or attempts to obstruct the Commissioner of Agriculture or the commissioner’s deputy or any of the commissioner’s assistants in the performance of the commissioner’s duty shall be fined not less than one hundred dollars or more than five hundred dollars.