Any bovine in which tuberculosis or brucellosis is diagnosed by the commissioner or his agent on physical examination, or by means of the tuberculin or brucellosis test, which is not immediately slaughtered under the supervision of the commissioner or his agent, shall be marked by inserting in its left ear a metal tag upon which is stamped a number and the word “Reactor”, and by branding the letter T or the letter B, not less than 2 nor more than 3 inches high on the left jaw.