Mo. Rev. Stat. § 267.220

Notwithstanding any provision in sections 267.170 to 267.410, the department shall allow and permit the owner of any animal found to be a reactor to retain the animal in quarantine and use the animal for breeding purposes in his own herd if necessary or desirable in order to preserve valuable breeding cattle; but, the permission shall not be granted if the state veterinarian determines that the eradication program would be adversely affected and permission shall not be granted unless the United States Department of Agriculture agrees that tuberculous * status will not be affected. The reactor animal may not be sold, transferred or moved except on a special permit issued by the department.