I just recently purchased two heifers from a brucelloisis free state and I live in a free state. One heifer is 13 mo. old and the other is 14 mo. old. Neither had been vaccinated for brucellosis. My question is.......should I vaccinate them now? I understand that if they are ever tested it could show up as a false/positive, but don't I need to protect these heifers before they are bred? My vet only says it is up to me if I do it or not. He's non-commital.