Seven Otago farms test clear for cattle disease


The first test results from seven of Van Leeuwen Dairy Group’s farms have returned negative for cattle disease Mycoplasma bovis.
The bacterial disease has previously been confirmed on two VLDG properties in the Waimate district, the first time the disease had been detected in New Zealand.
In an update on Monday, response incident controller Eve Pleydell said two further rounds of testing would be required on those seven farms before they could be declared free of the disease. Results were pending for the remaining seven VLDG properties.
Good progress was made during the weekend, as laboratory teams continued to test thousands of milk and blood samples from VLG farms and neighbouring properties, Dr Pleydell said.
To date, 2610 samples had been received. Nine of the 62 neighbouring properties had so far tested negative.
Dr Pleydell said it was important to find out if the disease was already occurring in other parts of the country.
The Ministry for Primary Industries was working with regional veterinary laboratories, Massey University and animal industry bodies to collect and analyse samples, including milk from cows with mastitis, discard milk and routine bulk milk samples.
The first samples from the regional laboratories would be arriving at MPI’s animal health laboratory, at Wallaceville, this week.
One of the rumours circulating was
the disease had come from imported semen.
At a public meeting last week, MPI specialist incursion investigator Tom Rawdon said he personally believed it was a “red herring”.
World Wide Sires New Zealand general manager Hank Lina said MPI had confirmed there was no evidence that resistance had developed to mycoplasma in imported bovine semen.
“MPI’s validation that imported semen was not the cause of the mycoplasma outbreak is bittersweet. We’re naturally delighted to have this confirmation of our standards and systems, but our hearts go out to the Van Leeuwen family, who are living through a farmer’s worst nightmare,” he said.
Meanwhile, a new diagnostic test for M. bovis, developed in Australia, is being used in both Denmark and Finland to investigate the prevalence of the disease.
Dr Nadeeka Wawegama, a research fellow at the University of Melbourne who has developed the test that could detect both sub-clinical and clinically infected cattle, said a few other countries had also shown interest in using the test.
When contacted to ascertain the effect of the disease in Australia, Dr Wawegama said Dairy Australia confirmed in 2006 M. bovis was in some dairy herds and it was considered a “significant” pathogen.
Once confirmed, the infected dairy cattle were culled, as there were was no antibiotic treatment.
It was also done to prevent the spread to the herd and milk from the infected cattle could also not be used on calves, so the economic loss was “very big”, she said.
Mycoplasma bovis which does not infect humans and presents no food safety risk can cause mastitis, abortion, pneumonia and arthritis.
Studies suggested at least 50% of Australian dairy herds were affected by subclinical mastitis, at a cost to industry of more than $60 million a year.
Otago Daily Times

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