M. bovis found on two NZ farms

The disease, although quite common in other parts of the world including Australia, has infected a dairy herd in South Canterbury which is the first recorded case of it in New Zealand. The Ministry for Primary Industries (MPI) is responding to the detection of the cattle disease Mycoplasma bovis in 14 cows in the dairy herd. About 150 cows on the property have clinical signs that indicate they, too, may be affected. MPI is now tracing movements of animals on and off the property to ascertain if other properties are at risk.

Photo: Mark Pasveer

Geoff Gwyn, the ministry’s director of response, said Mycoplasma bovis did not infect humans and presented no food safety risk. He said there was no concern about consuming milk and milk products. Ministry vets were informed of sick cattle at the property last week and the disease was confirmed 5 days later at the ministry’s Animal Health Laboratory. A team of officials are said to be “working hard at the farm to ensure the disease did not spread.”

No impact on human health

Federated Farmers dairy group chairman Chris Lewis said the important point to stress was there no impact on human health, and the disease did not affect milk products. Mr Lewis said: “It’s something I’ve never heard of before and I don’t have a clue about how it would have arrived here. The farmer had done everything right as soon as he noticed the symptoms in his cattle”. Restrictions forbidding the movement of stock from the farm have been put in place by the Ministry until the scale of infection is determined. Mr Gwyn said: “Right now we’re working with the farmer to contain the disease to the affected farm and treat the animals showing symptoms. We are very appreciative of his support in this work.”

According to Sydney University Associate Professor John House there is no treatment available for milking cows, which, if affected, have to be culled.

Mycoplasma bovis can infect both calves and cows and cause pneumonia, udder infection (mastitis), abortion, arthritis, tendinitis, middle-ear infection and endometriosis and is potentially fatal. The Ministry has urged farmers to contact their vet if stock show unusual levels of mastitis, abortions or present with arthritis or pneumonia. The disease spreads easily, including through nose to nose contact, feed, water and bedding material and by workers.

Mr Gwyn added: “If Mycoplasma bovis becomes established in a dairy herd, close to 100% of calves will become infected. However, they may not develop clinical disease or shows signs of being ill.”

Unclear how disease entered NZ

On 31 July it was confirmed that a second dairy farm in South Canterbury, that was already under biosecurity scrutiny, was confirmed positive for Mycoplasma bovis. At this stage it is unclear as to how or when the disease entered New Zealand.