M. bovis … what is it and what are we doing about it?

DairyNZ biosecurity readiness and response manager Chris Morley says mycoplasma bovis is extremely difficult to detect.
Photo Laura Bagrie

The Mid Canterbury farming community was rocked earlier this week with the announcement by the Ministry for Primary Industries that mycoplasma bovis had been confirmed as being on a farm near Ashburton. So what is the cattle disease, what are its risks and costs, can we get rid of it and what is the ministry doing to achieve that? Colin Williscroft reports.

Prior to mycoplasma bovis being discovered on a dairy farm near Glenavy in July last year, New Zealand was one of a handful of countries worldwide, another being Norway, where the disease was not present.

Very few people here, including most farmers, knew anything about it, despite it being common in most cattle-producing countries around the world, occurring throughout Australia, North America and Europe.

M. bovis causes illness in cattle including mastitis, abortion, pneumonia and arthritis.

It’s important to realise that the disease does not affect people – it is not a food safety risk.

DairyNZ biosecurity readiness and response manager Chris Morley told public meetings in Methven and Ashburton on Thursday that the disease is known as a “silent spreader” – cows can be infected but not fall ill.

That’s one of the things that makes it difficult to detect – it hides, often not presenting itself until cows come under some sort of pressure and can surface months later.

Because of that cows carrying the disease often appear healthy, so in a country like New Zealand where stock movement between farms is common, cows can be moved around with no-one being any the wiser as to them carrying the disease until it’s too late.

If you want a human analogy think herpes. It might be in your system but most of the time you’d never know. However, a bit of fatigue or other health problems and everything changes.

A concern, but some perspective

As mentioned, the disease is common internationally. Most other countries have it in their normal cattle supply and they successfully manage it.

M. bovis is not listed with the OIE (the world animal health organisation) and, according to MPI, the disease does not present a trade risk for New Zealand animal products. It will not affect prices paid for New Zealand export beef or prices on Global Dairy Trade.

That’s not to take away from the devastation that will be felt by those whose herds have tested positive. Some of those people will have had their herds culled, while those who haven’t still have that prospect hanging over them.

On top of that, because no-one in this country wants the disease on their farm, they face being ostracised by those around them.

So why the worry?

Despite it not affecting humans, M. bovis poses significant animal welfare risks, which come at a cost to both the cows themselves and the farmers who work them.

If we’re looking at purely financial implications we’re talking higher vet bills to treat animal health problems and lower production due to either sick animals or abortion. Either way, not things dairy farmers want to consider.

Because of that, and the fact the disease has not been present before, no-one wants a bar of it.

Another concern is that no-one is sure how the disease arrived in New Zealand in the first place.

MPI response incident controller David Yard says the ministry is looking into possible pathways, including imported embryos, semen, medicines, animals, feed or used farm equipment, but the reality is they may never know the answer.

The local situation

The Ashburton property that tested positive for M. bovis was not the one initially being investigated. That property is still providing inconclusive test results, despite MPI saying it is highly likely it will end up with a positive result.

The confirmed property was identified through a milk surveillance programme, not through tracing suspected properties connected with the van Leeuwan farms where M. bovis was first discovered in New Zealand.

MPI’s Justin Mercer told the Mid Canterbury meetings that there was no link identified between the local property and those already identified as infected, but much of the investigation was still to be completed, with the ministry trying to trace movements between the local infected property and about 30 other farms.

What Mercer could assure farmers was “until we have a clearer picture, we won’t be culling further herds”, referring to the herds culled early in the outbreak, which led to the destruction of 4800 cattle.

Not just dairy

Much of the focus right now over M. bovis has been on the dairy industry but there are also implications for beef farmers.

Beef + Lamb New Zealand is working closely with the Ministry for Primary Industries (MPI) on its response to M. bovis and chief executive Sam McIvor is encouraging all beef farmers and rural contractors to help protect their farms and businesses by following the guidance available on the MPI website, keeping an eye out for unusual symptoms in animals and reporting them to their vet, and ensuring all farm records and NAIT records for stock bought, sold or moved are accurate and complete.

MPI has also been working with staff at Anzco’s Mid Canterbury feedlot over testing procedures.

Current containment controls

All infected farms and those with suspect results are in a “quarantine lockdown” through restricted place notices, Mercer said.

That means no animal or risk goods on or off, while any movement of cattle requires a permit from MPI and all vehicles have to follow a cleaning and disinfection process when they leave.

He said staff from AsureQuality (MPI’s managing partner for biosecurity) are ensuring that cleaning, disinfecting and permit requirements are being complied with.

What is MPI testing for?

MPI veterinary incursion investigator Kelly Buckle says given that M. bovis can hide in infected cows, showing up months later, the ministry is testing for both the actual bacteria and the cows’ immune system response to that bacteria, with tests targeting up to 130 cows in a herd.

She says that before the ministry can make decisions about how to deal with the disease, it needs to find out how far it has spread, so it is taking a multi-layered approach to its testing programme.

This includes finding out as much as it can about infected farms, bordering farms, stock movement and both district and nationwide bulk and discard milk.

MPI is also working with milk companies on a nationwide surveillance programme that involves monitoring herds by testing milk from mastitis-affected, lame or otherwise sick cows. The programme begins in Mid Canterbury next week.

On-farm biosecurity

Morley says it’s time farmers stepped up to the plate in this area.

“Don’t rely on others to protect your patch, protect it yourself – we all have a role to play,” he told those at the Mid Canterbury meetings, referring them to advice on the MPI and DairyNZ websites.

“Record all animal movements on and off your farm,” he said, even if that task was one viewed as an unwanted chore in the past.

It’s been acknowledged that compliance with the National Animal Identification and Tracing Scheme (NAIT) is an area where farmers are letting themselves down and Agriculture and Biosecurity Minister Damien O’Connor says he’s told officials to take a tougher approach with farmers and all other users who do not meet their obligations under the scheme.

He says most animal movements to sale yards and meat processors are recorded within the required 48 hours after they are completed, however a large percentage of farm-to-farm movements are not recorded.


MPI has a compensation plan in place for those affected by restricted place notices and notices of direction but Yard says anyone thinking of going down that path needs to realise they will have to prove they will be out of pocket.

He says compensation is available for damage or destruction of property and money lost due to restrictions imposed under the Biosecurity Act on the movement or disposal of goods.

“Farmers will be compensated but under the (Biosecurity) Act they will have to prove they will end up no better or worse off, so it’s not a licence to pursue a wishlist.”

It’s also a lengthy process that will require accurate records, he said.

Transporting animals

Farm service providers, such as transport companies, are stuck between a rock and a hard place over the biosecurity concerns brought about by mycoplasma bovis.

MPI’s Justin Mercier says vehicles pose only a negligible security risk and it is safe for cattle to be transported from infected farms.

He said there is a strict cleaning and disinfection protocol to be followed and MPI has contractors to ensure the rules are being followed.

Mercier does have some advice for farm service providers.

“Farms should be using routine on-farm biosecurity practices to minimise risk to their animals. Service providers can help minimise risk by complying with the farm’s cleaning and disinfection requirements.”

He says it’s important that service providers don’t arrive on-farm unannounced.

“Let the farmer know you plan to visit their farm and ask their requirements,” he says, adding that it’s important they work with farmers over biosecurity on-farm.

“Clean and disinfect footwear, protective clothing and equipment before coming on-farm.

“Be proactive, assure farmers of your hygiene practices.”

Mercier acknowledges that extra cleaning of equipment such as trucks will add time and financial costs that had not been considered necessary in the past.

However, it was for everyone’s benefit that farmers and providers work together to make sure there are no shortcuts taken in this area.