Field operations in the Brucellosis Eradication Scheme

Abstract

The New Zealand Brucellosis Eradication Scheme was introduced in 1971, following five years of compulsory calfhood vaccination with Brucella abortus strain 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.

Blood samples are collected into evacuated tubes from the caudal blood vessels of cattle by teams of technicians led by a livestock officer. Sera are separated at district processing centres and sent to the Central Brucellosis Laboratory for complement fixation testing. Sometimes the brucellosis card test is used as a screening test at the district laboratories to reduce the workload at the central laboratory. Herds are tested every 60 days until a test clear of reactors is obtained. Two clear tests 6 months apart allow a herd to be accredited free from brucellosis. When Brucella infection persists in a herd, or when an accredited herd becomes re-infected, the district veterinary officer carries out an on-farm investigation to define the nature of the problem. Herds, once declared free of brucellosis, are maintained under surveillance by bulk milk ring tests for dairy herds, and periodic blood sampling in beef herds, and also by the routine investigation of all abortions.