M. bovis eradication phases explained
The 3 main phases to Mycoplasma bovis (M. bovis) eradication are:
- delimiting
- provisional absence
- confidence of absence.
Delimiting
As at June 2022, we are in a delimiting phase. As part of this phase, we are using network surveillance (checking for infection within the infection network and properties linked to the network) and background surveillance (checking for infection outside the network).
There is more work to be done in this phase as we clear infection from all confirmed properties and finish the network surveillance activities.
Provisional absence
The programme will use background surveillance to confidently declare that New Zealand is free from M. bovis. To achieve this, our bulk tank milk screening and beef and drystock cattle surveillance will need to run for 1 dairy production cycle (at least 2 years) without finding any Confirmed Properties.
Confidence of absence
If no infection is found during the provisional absence phase, we will move to a confidence of absence phase.
In this phase, background surveillance will continue for another 2 to 3 years.
Once we have reached a very high level of confidence, we will have achieved our objective of eradicating M. bovis from New Zealand.
Declaration statement to world authority
Once we have confidence of absence, our intention is to submit a declaration of freedom to the World Organisation for Animal Health. We need to give strong supporting evidence of our declaration.
The background surveillance data gathered during the provisional absence and confidence of absence phases will form a key piece of evidence in this declaration.

Maintaining good on-farm biosecurity essential
The need to practice good biosecurity is imperative through all 3 phases. If M. bovis is uncovered during either the provisional absence or confidence of absence phases, the country would need to return to an earlier phase. This would increase the length of time required to eradicate the disease.