If, after such examination, tubercular animals are found, the department shall have authority to order such disposition of them as it considers most desirable and economical. If the department deems that a due regard for the public health warrants it, it may enter into a written agreement with the owner, subject to such conditions as it may prescribe, for the separation and quarantine of such diseased animals. Subject to such conditions, the diseased animals may continue to be used for breeding purposes.