When the commissioner has reason to believe that the test or tests were not made in a competent or reliable manner, he may require that such animals shall be confined in quarantine at destination or other designated place, and be subjected to a retest at the expiration of a period not to exceed 60 days. If, upon testing, they shall be found to be infected with any contagious or infectious disease they shall be subject to the provisions of N.H. Rev. Stat. § 436:10-20.