More update
South Canterbury rich-lister's diseased cows may have been sent to other farms
Farms outside the van Leeuwen Group are now being investigated to check if they received cows from infected farms.
Officials have confirmed the disease-hit van Leeuwen Group has transported cows to other farms.
It raises the potential for the cow disease Mycoplasma bovis to have spread beyond the group's 16 farms in South Canterbury.
"As per normal dairy farming practice, some animals have been bought and sold from the group previously. We have traced back six months, and in that time a small number of transactions have occurred," Geoff Gwyn of the Ministry for Primary Industries (MPI) said.
Aad and Wilma van Leeuwen's robotic dairy barn at Makikihi, South Canterbury. The disease has been detected on two surrounding farms the couple own but not at this giant barn.
At the same time he announced bulk milk tests would be done on tankers across the country next week to see if the disease outbreak was more widespread.
The tests would be based on a sample of more than 200 milk tankers.
READ MORE:
* Cow disease found in second South Canterbury dairy farm
* Rich-list South Canterbury farmer devastated by impact of cow disease
* Cows infected with Mycoplasma bovis must be destroyed now: Damien O'Connor
Farmers are concerned about the potential spread of the disease Mycoplasma bovis.
Mycoplasma bovis is a disease affecting dairy cows which causes mastitis, lameness, pneumonia and abortions. Once a cow is infected, it is impossible to be cured and has to be put down.
Widespread in the rest of the world, it was detected in New Zealand for the first time last month on a van Leeuwen farm. It has now been discovered on a second farm within the group owned by the rich-listers, who are estimated to be worth $60 million.
MPI said so far 25 animals on the first affected farm had been euthanised by the farmer for welfare reasons. A further group of affected animals had been checked by a vet and were fit for transport to slaughter.
"People in the area will start to see stock movements and I understand this is something that is worrying local farmers. I'd like to reassure them that any risk from transporting cattle from the van Leeuwen farms to processing plants has been assessed as negligible and is being managed. This movement of the stock is being permitted by MPI and vehicles will be cleaned and disinfected after use under MPI supervision," Gwyn said in a statement.
Mycoplasma bovis posed no risk to human health or the safety of food products – meat or dairy.
"There is no reason to hold meat and milk from the affected farms back from processing," Gwyn said.
Those farms outside the van Leeuwen Group that were being investigated were not yet under "Restricted Place Notices". They were being checked on a "precautionary basis to build our picture of the disease distribution, but at this time there is not a sufficient level of risk to require the imposition of controls".
Labour primary industries spokesman Damien O'Connor queried whether local farmers were being contacted by MPI.
"I was told by a neighbouring farmer who had to walk his cattle past one of the affected farms that he had not been advised what to do by MPI, although he had been in touch with NAIT [the animal tracing agency]," O'Connor said.
Meanwhile, North Island dairy farmers are questioning whether cattle should be allowed to be transported from the South Island and have their herds potentially threatened with the cow disease.
They did not want to be named, but said they had contacted the Ministry for Primary Industries (MPI) and Federated Farmers with their concerns.
Federated Farmers' dairy group chairman and Waikato farmer Chris Lewis said it was a "good question" as to whether authorities should be closing off Cook Strait from cattle transport.
"At the moment there are concerns up here [in the North Island] and farmers take these things very seriously. The question needs to be asked of MPI: do they have confidence in the biosecurity arrangements around those farms?"
MPI responded that it regarded transport across Cook Strait as a safe activity.
"MPI considers that its current movement restrictions imposed on the farms in the van Leeuwen Dairy Group are sufficient to manage the risk as it is currently understood.There are certainly no stock being moved from the affected farms to the North Island."
Lewis said although the disease was common elsewhere, as an island nation New Zealand wanted to protect its status of having fewer diseases than in other countries.
"We have had a lot of pests and diseases come into the country. Here we have the opportunity to get rid of this disease because it is on only one or two farms, so we have to make the most of this opportunity."
Gwyn said the the main way the disease could spread was through direct contact between cattle, such as nose to nose.
"All the other potential factors such as on equipment, clothing and footwear, effluent and vehicles present a comparatively low risk."
MPI is holding a community meeting on Wednesday to update progress in the response. The meeting is at 11am at the Papakaio community hall, just north of Oamaru.
(20min delay)