Animals to be added to a herd shall comply with the following requirements: From another herd of like or higher status, no retest shall be required; from a herd of lower status, the animal to be added shall pass two negative tests not less than sixty nor more than ninety days apart, during which time it shall be kept separate from the herd. All retests for addition shall be made at no expense to the state. Animals which are added to herds under supervision, which have not been retested and maintained apart from the herd as required, are not eligible for remuneration if they react. No person shall remove ear tags from any animal or exchange them from one animal to another.