The New Zealand Brucellosis Eradication Scheme was introduced in 1971, following five years of compulsory calfhood vaccination withBrucella abortusstrain 19. Each of the 25 veterinary administrative districts was divided into zones and the eradication effort was concentrated on one zone at a time, ensuring best use of manpower and resources and orderly expansion of the scheme to involve all eligible cattle by 1977. Every effort was made to inform each farmer of the requirements of the scheme and to scheduling the testing programme to fit the farmer's management system.