For more than sixty years, New Zealand has justified widespread possum control, including extensive aerial 1080 operations, on two principal grounds: protecting native biodiversity and reducing the spread of bovine tuberculosis (TB). Few would argue that protecting livestock and wildlife is unimportant. The real question is whether today’s programme still targets the greatest sources of risk, or whether it continues to follow assumptions that deserve renewed scrutiny.
Bovine TB remains a significant issue for the cattle industry, and New Zealand has rightly invested heavily in controlling it. Yet disease management should continually be tested against evidence. Scientific understanding evolves, farming practices change, and so too should public policy. A programme that began decades ago should not be immune from critical review simply because it has existed for a long time.
Much attention has focused on possums as wildlife reservoirs of infection. Considerably less public discussion centres on other recognised pathways, including the movement of infected cattle between farms. Illegal or uncontrolled stock movements have repeatedly been identified as an important means by which TB can spread. If this pathway contributes significantly to new outbreaks, it deserves at least the same level of public attention as wildlife control.
Questions also remain about diagnosis itself. The tuberculin skin test is an established screening tool, but like any screening test it is not perfect. Some cattle identified as reactors are subsequently found to have no visible TB lesions during post-mortem examination. That does not automatically mean the test is wrong, nor does it invalidate the wider eradication programme. However, it does remind us that screening tests have limitations and that policy decisions involving compulsory slaughter deserve continual evaluation rather than unquestioning acceptance.
Equally important is measuring success. After decades of aerial poisoning programmes, what proportion of TB reduction can be directly attributed to possum control? How much results from improved herd management, better surveillance, stricter movement controls and modern biosecurity measures? These are not anti-science questions. They are exactly the questions that should accompany any long-term public programme involving substantial environmental intervention.
The environmental costs also deserve honest consideration. Aerial 1080 operations affect large areas of public land used for hunting, tramping, fishing and other outdoor recreation. Whether one supports or opposes its use, such operations impose environmental and social costs that should be justified by clear, measurable outcomes. If alternative measures can achieve similar or better disease control with fewer environmental impacts, they should be openly examined.
None of this argues for abandoning TB control. Nor does it argue that possums play no role in disease transmission. Rather, it argues that public policy should remain evidence-led, continually reviewed, and directed towards the greatest sources of risk rather than simply continuing historical practice.
The issue is not whether bovine TB should be controlled. It is whether New Zealand is asking the right questions about how best to achieve that goal.
There may be no goal to achieve. The late Richard Prosser, a top MP, in Parliuament’s question time asked Ag Minister Nathan Guy about possums and Tb. Guy replied 9830 possums were tested in a study – none had Tb.
Yup. I still haven’t found any proof. But isn’t it terrible that people can blame a bovine disease on another animal that DOC has already demonised and everyone just believes it and slaughters it with impunity.
The late Bill Benfield, an ardent conservationist, in his book “The Third Wave” wrote the possum, ‘a marsupial about the size of a cat, enjoys the worst press of all our exotic animals. We are told it is responsible for the canopy collapse in our forests, for the presence of bovine Tb in our cattle herds and for the predation upon our native bird life.”
The possum- Tb link is a myth.
The level of Tb in New Zealand cattle is far below, in fact many hundreds of times below, world standards for a nation to be declared Tb free. The world standard for “Tb free” was 0.1% infection rate, yet for many years New Zealand has been at 0.0014% and even below for many years now.
Bureaucrats keep themselves in a “cushy” job by inventing an imaginary pest.
I think it was about a dozen years ago, a Marlborough farmer brought to his farm cattle from two TB infected areas, i.e., Inangahua and Clarence Reserve to the then Tb-free Northbank on the Wairau valley. Tb outbreaks then occurred.
The Animal Health Board (now OSPRI) then publicly blamed possums and in league with the Department of Conservation, dropped 1080 poison over the adjoining Richmond Forest Park.
I spoke to an AHB vet, a pleasant chap. I said “it’s not possums, it’s Tb introduced on stock trucks by farmer X. You should be prosecuting him instead of blaming possums and dropping poison on public lands.”.
He didn’t contest what I had said and just smiled knowingly.
The farmer was prominent in Federated Farmers.
Nevertheless TB continued at the area. AHB used the skin test to carry out testing, but the skin test has an error rate according to sources, of 25-30% error -waste of time. that error means animals with Tb can be passed clear of Tb by the error prone skin test to remain in the herd and infect any stock whose immune system is shaky.
Farmers and vets call those infected but passed as clear animals, as “sleepers”.
One farmer fed up with continuing reactors, personally paid for blood tests – much more accurate (98%? I’ve been told) and identified 5 sleeper animals that had been passed by the skin test. The infected animals were removed and he was Tb clear. No more reactors.
In the meantime AHB/DoC’s 1080 drop killed off a flock of keas that lived on nearby Mt Patriarch, plus local wekas and heavens knows how many other birds.
One farmer got so fed up
There is no political will to change our current paradigm, as regards possums, TB, and Aerial 1080.
As Goebbels and Hitler discovered, so too have the powers-that-be here in New Zealand.
If you tell a lie that is big enough .. and you tell it often enough .. then people will come to believe it is true.
If somebody floated the idea as brand-new today .. let’s indiscriminately, aerially spread thousands of tonnes of a WHO Class 1A ecotoxin .. capable of killing everything that consumes oxygen .. proven to kill indigenous native species (eg Kea) .. in direct contravention of the Manufacturer’s Warnings (clear aware toxic carcasses, and don’t apply anywhere near streams or waterways) .. across millions of hectares of otherwise pristine bush and backcountry .. it would be dismissed as absurd .. totally, unthinkably, environmentally unacceptable.
And yet that is exactly what we continue to do today.
Everybody is comfortable with it (almost).
The funding streams are established.
The public have totally accepted the lie.
Anybody who objects is marginalised, and discredited.
That’s despite the fact we are the only country in the world .. that does what we do .. in the manner in which we do it.
No other country in the world is so stupid …
There’s too many people making a lot of money out of keeping the Tb infected possum myth alive and Tb Free have promised to stand with DoC until 2050 when NZ will be pest free which will never happen.
Same again. Helpless and hopeless blame possums. If you want to know huu is w to avoid tb ask a tb free farmer.
Don’t muck around feeling sorry for yourself. Look carefully at what you are doing and change what is wrong.
Reduce overcrowding and under feeding, increase quality feed and reduce stress.
You may not be able to totally mitigate the stress of bad weather or calving but you should see what your tb free neighbours do and ensure you are doing your best.
Itbb by is often obvious when a farm changed hands and tb goes away. Think about that.