What does TB freedom mean?

In the context of the TB Plan review, ‘TB freedom’ means confidence that there are no TB infected farmed cattle or deer herds in New Zealand, and there are no infected possum populations likely to cause re-infection of livestock.  Currently for possums disease freedom is defined as achieving at least 95% confidence, through a structured ‘Proof of Freedom’ process, that TB is no longer present in an area.

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What does eradication mean?

In the context of the TB Plan review, ‘eradication’ of TB is defined as having a very high level of confidence, based on modelling of data collected through programme activities over time, that TB is no longer present in any livestock, possums, pigs or deer.

Eradication is a step beyond TB freedom because it’s about a high level of confidence that TB is gone from all species of interest (livestock, possums, pigs and deer), over a longer period of time.

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Does eradication mean eradication of possums? 

No – it means the eradication of TB disease, by suppressing TB vectors (possums) to low-enough density for the time required to ensure disease dies out of the possum population.  Once the TB disease is gone, the possum population may recover unless control is undertaken by others.

OSPRI will still need to consider how to maintain good operational relationships with regional councils and others undertaking pest control work nationally.  

 

What does elimination mean?

In the context of the TB Plan review, ‘elimination’ is the act of removing infection from the target population, that is, the process rather than the end result.

 

What happened to the objective of achieving TB freedom in livestock by 2026? That’s what it says on OSPRI’s website?

The milestone of TB freedom in livestock by 2026 was set in 2015, the last time the TB Plan was reviewed. New Zealand has come very close to that, with around 0.01 percent of herds infected (15 out of about 75,000 at 30 June 2025). However, as has been seen in recent years, there will continue to be outbreaks while reservoirs of disease remain in the possum population. It is not practically possible to achieve or maintain absolute zero herd infections until the disease is no longer present in possums.

OSPRI will update its operations, including its website, once final decisions are made following the review.

 

Where does the figure of 75,000 herds come from?

For the purposes of TB management, OSPRI defines a herd as ‘all cattle or deer under the day-to-day management of a single Person in Charge of Animals (PICA). This includes a single animal or a large group’.

This definition aligns with international definitions used in monitoring TB prevalence.

Using this definition, there are 75,107 herds in New Zealand, as stated in the OSPRI 2023-24 annual report.

 

Will ‘prioritising possum hot spots’ take the focus away from herd freedom from TB?

On the contrary, the intent is to eliminate TB from possums so that they don’t keep reinfecting herds. This will help us achieve herd freedom.  Alongside this priority, OSPRI will continue management of infected herds and surveillance testing to limit the spread of infection.

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What will prioritising hot spots mean for other areas where there are still infected possums?

The programmes in other areas will continue until those areas are cleared.

 

Is the use of aerial 1080 necessary?

Yes. The review confirms that aerial 1080 is the optimal, most cost-effective tool for larger, ‘landscape scale’ possum control operations, such as difficult-to-access steep and remote back country and extensive areas of South Island pastoral lease and Crown lands.

The alternative, greater use of ground control (trapping and toxins), is significantly more expensive and cannot achieve the level of coverage necessary to knock down possums in steep and difficult to access areas, potentially allowing the disease to persist in reservoirs of infected possums, from where the infection will spread again.

 

Are there any new technologies that could reduce the reliance on aerial 1080 and/or improve the cost effectiveness of the programme?

There is a lot of research and development underway, with a number of emerging technologies that may be useful for disease diagnosis, wildlife vector surveillance, and control practices over the next decade.

This includes pest surveillance options such as drones and thermal imaging to estimate possum numbers in less-forested areas, and advances in testing for infection.

However aerial 1080 remains the best possum control tool available to deliver rapid, effective and large-scale control over landscapes where the terrain or vegetation cover prevent reasonable access for workers on the ground.

 

Will the targeted testing approach come with greater risk of more infected herds?

While there would be less frequent testing, OSPRI is confident it can target higher-risk herds for testing, reducing the chances of missing an infection. Over time, as funds saved from targeting testing are used to eliminate the disease from possums, then the risk of re-infection from possums will drop.

 

What will happen with possum control in areas where TB has been eradicated?

Pest control carried out under the National TB Plan does deliver significant biodiversity benefits.  However, the control of possums and other pests is only carried out under the Plan where control contributes to the achievement of the Plan’s TB-related objectives.  As is already the case in many TB free areas, agencies with pest control roles (e.g., regional councils and the Department of Conservation) and individual landowners will develop and fund their own possum control plans and programmes.    

 

What is happening with wild deer and pigs?

While wild deer and pigs can become infected with TB in the wild from infected possums, the disease does not spread from them to farmed livestock.

Research over many years has shown that prolonged possum control results in the disease reducing across possums, wild pigs and wild deer.

 

But isn’t TB in wild pigs and deer a problem for farmed herds in other countries?

In New Zealand there is a much lower density of wild pigs and deer, and secondly there is less opportunity for wild pigs and deer to interact with farmed livestock.

For example, in Michigan, United States, wild deer were eating out of farm feed bins, while in Spain wild pigs were using the same watering holes as farmed cattle.

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What’s DOC’s role in possum control?

The Department of Conservation (DOC) commits resources to possum control at priority sites to ensure the long-term survival of species and the ecosystems that support them https://www.doc.govt.nz/nature/pests-and-threats/animal-pests-and-threats/possums/

DOC also has a role in administering conservation land and in some areas works closely with OSPRI on possum control on land it administers.

There are benefits to the TBfree programme from DOC’s possum control activities, and DOC was an observer on the TB Plan review. However, TB control and eradication is not DOC’s primary focus.

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Why is there a projected shortfall after 2031?

Primarily because the previous budget forecast back in 2015 did not account for inflation. 

The intent was that the amount farmers (and the Government) have to contribute would start to decline from 2031. However the impact of inflation means that there has been less money available for possum control, so the risks and infection levels have not fallen as quickly as anticipated in 2015.

 

What will happen to farmer levies after 2031?

It’s too soon to say. The projected shortfall is based on the modelled annual cost, including accounting for inflation going forward, but over the next few years more work will be done to confirm what the costs beyond 2031 will actually be.