Ashley Cullen tags and records details of young calves on his farm in compliance with M.bovis. Photo/ John Stone
Northland's position as a major beef producer makes it particularly vulnerable to cattle disease Mycoplasma bovis, a regional farming leader says.
Northland Federated Farmers dairy chairman Ashley Cullen said beef farming systems had highly mobile stock flows, making them particularly vulnerable to M. bovis due to the large number of young stock that farmers brought into the region.
Northland farmers buy in stock from around the country and the reverse happens too.
The typically younger stock is grown to heavier weights to produce beef for New Zealand's export and local markets. Young stock could be sourced from dairy or beef farmers — as dairy, dairy beef cross or beef breeds.
A single animal might change hands five times in its lifetime.
Cullen said this made the need for farmer compliance with New Zealand's national animal identification and tracing scheme (NAIT) critical.
M. bovis was first confirmed in New Zealand in July 2017 on a South Canterbury farm.
Canterbury (in particular Ashburton), Otago and Southland have been the disease's epicentre, with three-quarters of New Zealand's confirmed M. bovis properties since then.
General stock movements helped its spread nationally.
Cullen said a ban on transporting cattle from the South Island across Cook Strait should have been put in place soon after finding M. bovis in New Zealand.
"That would have given us the best chance of limiting the disease's spread to the North Island."
Authorities clearly had not realised the full implications of confirming New Zealand's first M. bovis case on a farm near Oamaru in July 2017.
Northland is one of five regions in New Zealand MPI figures currently show to have farms with confirmed active, presence of the disease along with (in ranked order) Canterbury, Southland, Otago and Hawke's Bay. The disease's presence predominates in Canterbury and the South Island generally.
The South Island has 12 properties under the strongest 'restricted place notice' quarantine control category for confirmed active, M. bovis presence, along with the six North Island properties bringing New Zealand's total number of properties in this category to 18.
I wouldn't wish M. bovis on my worst enemy.
The 'restricted place notice' quarantine category has been placed on 14 Northland properties since the national eradication campaign began — nine now cleared with the five properties remaining.
A further 55 properties have been in the second strongest 'notice of direction' quarantine category for the possibility of having the disease — 32 now cleared with 23 properties remaining. Both these quarantine categories are issued under the Biosecurity Act 1993.
"The Northland figures are an alert more needs to be done to deal with the situation here at the top of New Zealand," Cullen said. "They're also an alert we need to be vigilant. Farmers need to be more proactive on sorting out where we're getting our animals from."
Still lots of issues
Tracking and tracing stock movements is one of the major M. bovis identification methods. It was used to first identify the disease in Northland through tracking cattle that came into the region from infected properties.
M. bovis hits dairy and beef cattle at all ages. Dairy and beef farming are closely linked with the former supplying much of the young stock the latter then grew on.
Cullen said there were still a number of issues with farmers wanting to be sure any cattle coming onto their farms were from an M. bovis-clear property.
New Zealand's NAIT scheme was a major tool in helping make sure any cattle coming onto farms were from M. bovis free farms but it had its weaknesses.
"A Northland farmer might buy in young stock, the NAIT system identifying the property of their vendor," Cullen said.
"But that vendor might have previously bought the Northland-bound stock on to his own property from a number of other farms to put together an adequately-sized lot to sell in the north. The national tracing system doesn't show where those collated animals originally came from."
Northland lifestyle blocks posed a particular M. bovis risk in this sense.
"I'm concerned about the number of lifestyle blocks in Northland. Those on these blocks may not always know about the legal requirement for all stock movements to be recorded through the NAIT system. A lot of lifestyle block animals could be sold on Trade Me then travel for miles."
Latest Ministry for Primary Industry (MPI) figures in New Zealand's almost $1 billion Mycoplasma bovis eradication campaign show Northland has five currently active confirmed Mycoplasma bovis properties — the biggest number of farms in this category in the North Island.
These farms are under the eradication campaign's strongest 'restricted place notice' quarantine category.
Changing practices
M. bovis is changing New Zealand farming practices.
Closed dairy herds, double fencing, using full artificial insemination to produce the next season of dairy calves rather than including a bull for the tail end of mating, buying runoffs rather than sending stock off farm for grazing and using only virgin bulls for mating are among these changes.
Maungaturoto-based Cullen does not have the disease on his farm and wants to keep in that way.
"I wouldn't wish M. bovis on my worst enemy."
He has adopted a closed-herd approach on his 200-cow dairy herd as part of staying M. bovis free. This means, in principle, not buying in stock — but when he has to, making sure as best he can it is from an M. bovis free property.
The NAIT scheme doesn't identify M. bovis status, his efforts relying on asking vendors about their M. bovis status.
Cullen said it was important to check the M. bovis status of all farms adjacent to properties a farmer was buying stock from — the disease spreads by physical contact between animals.
Double fencing boundaries between properties was a possible option to help fight the spread of the disease.
This would mean having the usual property boundary fence and a second fence, 5 metres inside that boundary fence.
Neighbouring farmers doing the same could create a 10 m buffer between properties that could then be planted in trees.
Double fencing might take out about 5 per cent of a paddock's grazing area but was worth it in the long term if it avoided M. bovis infection.
New Zealand is partway through a near $1 billion world-first M. bovis eradication campaign that began after July 2017 testing on a South Canterbury farm identified it in this country for the first time.
The actual or potential presence of M. bovis was stressful for farmers, Sue Rhynd, Northland Rural Support chairwoman, said.
"The disease is the same as a flood or a drought, it has the same impact on your farming operation. Make sure you're prepared."
Rhynd said farmers facing even a hint of potentially having M. bovis on their property should be proactive about talking with their dairy company, area manager, supporting professionals and banks.
"It's really stressful if you don't have a good understanding of the business and your support people don't either."
Farmers needed to make a plan to deal with M. bovis.
Rhynd said affected farmers should make sure all their farm records were up to date, particularly those that dealt with livestock movements through (NAIT). They should also make sure budgets were current. It was important they stayed ahead of the game, preparing for what was to come next in dealing with the disease on their property.
M. bovis symptoms include abortions, untreatable mastitis in dairy and beef cows, severe pneumonia in up to 30 per cent of infected calves, swollen joints and lameness (severe arthritis) in all ages of cattle.
"Farmers are doers by nature," Rhynd said. "They have their plans for what they're going to do with their business. When a disease like Mycoplasma bovis is likely, it stops them in their tracks."
Self-care was critical: "That's the most important thing because you can't make good business decisions if you're not sleeping well, eating well and looking after the basics. Sometimes it's as simple as just breathing properly."
110,000 slaughtered
Latest Biosecurity NZ figures on the Ministry for Primary Industries M. bovis website show the eradication campaign has resulted in more than 110,000 cattle being slaughtered across the country and almost 840,000 disease identification tests have been carried out to date.
A regular monthly milk testing regime has just been introduced to New Zealand last month as part of the country's ongoing M. bovis eradication programme.
This regular monthly bulk tank milk testing is done at the farm dairy when milk tankers collect milk.
Results showing the disease's potential presence through the milk testing are then followed up with on-farm livestock blood testing. Farms with more than 10 per cent of stock showing the presence of M. bovis antibodies are then put on to 'notice of direction' quarantine category.
The bulk tank milk testing can throw false positive results. As many as 80 per cent of farms undergoing further livestock blood testing are shown to not have the disease.
Placing a farm under 'notice of direction' quarantine means potentially-infected stock can't be moved off the property.
This doesn't necessarily apply to the whole property, focusing rather on specific infected stock which are kept separate from others on the property.
Authorities categorise the possibility of having the disease in two categories, the likelihood of its presence being greater under the 'notice of direction' quarantine category rather than the lower likelihood of it being on properties placed under the less strict active surveillance.
MPI's chief science adviser Dr John Roche last month said it was important for New Zealanders to realise there was another 12 to 18 months of heavy lifting ahead in eradicating M. bovis — tracing and casing farms and depopulation before shifting to longer-term background surveillance.
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