Mycoplasma bovis: European semen is the likely source

It is now increasingly evident that European-sourced semen, imported legally but containing live Mycoplasma bovis that survived the antibiotic cocktail, is the likely source of the organism in New Zealand dairy.

The evidence suggests it struck first in Southland, but there is a likelihood that the same semen has struck on other farms, and then spread from there via progeny.

It is also likely that Mycoplasma bovis arrived in New Zealand via this semen by late 2014 or even earlier.  This is an important issue because so far MPI has only focused on events since the end of 2015.

If the above statements about semen and time of entry are correct, then there are profound implications for the eradication program. In effect, we could be fighting six or more fires from the different strikes and possibly more that have yet to be identified.

The above explanation is also the likely reason why the spread of the infection has been much faster than MPI and its advisers expected. The stealth bomber dropped its load in multiple places.

The reason that I believe semen is now the most likely source of the disease is that no other single source can explain the range of infected properties.  I have been puzzled for many weeks by MPI’s somewhat soothing claims about farm linkage, which did not fit with the evidence famers were telling me.

What I found was that three infected Canterbury farms that lacked obvious live animal links to either the Van Leeuwens or Zeestratens, plus the Van Leeuwens and the Zeestratens themselves, were all using the same source of Northern European semen. This does not constitute proof, but it does provide a pointer.

The official position of MPI to date has been that there has been only one outbreak. Initially, MPI said that it started in South Canterbury and that it was confident the outbreak started in 2017. I have seen official correspondence from MPI stating that MPI was only interested in animal movements for 2017. Eventually they had to concede that it arrived in Southland well prior to this, most likely by their current calculations at the end of 2015 or early 2016.

MPI has not publicly stated how it thinks the organism entered New Zealand, but the inference is apparent from other actions. Quite clearly, MPI has recently been of the perspective that it was likely to have been through infected veterinary drugs, perhaps imported illegally. That source is still a possibility, but there are increasing challenges to that likelihood, including that it does not explain the rapid spread.

MPI’s focus on veterinary drugs was highlighted by its warranted raids on three properties, including a veterinary clinic based on Waiheke Island. Also, within the MPI Pathways Report as to how Mycoplasma bovis might have got to New Zealand, all reference to veterinary drugs, including even the inclusion of the category, was redacted prior to release of the report. For those who could identify the missing category, that redaction highlighted where MPI’s detective focus lay.

A key piece of evidence as to how the disease might have got to New Zealand is the genetic tracing.

So far, the New Zealand variant of Mycoplasma bovis is unique within the international Mycoplasma bovis database. However, it is only one locus (mutation) away from its parent, an apparently old European variant, with this variant having also been identified, but less common, in the United States.

Mycoplasma bovis genetic variant map; NZ variant dark green with red outer circle. Source MPI Paper 2017/1


The synthesis of information from within the genetic map suggests that it probably came from one specific source in Europe.  That does not preclude the possibility that variants of Mycoplasma bovis have been here for a long time. But it does indicate that all of the limited samples tested so far have likely come from one European source. But note that I said this comes from the limited samples tested for genetic variation. There is scope for debate about the interpretation of the map.

If I am correct, and semen is the source, then no farmer is to blame for the arrival of the disease. Also, the likelihood is that no importer of semen has broken the law. Rather, the laws around importation of frozen semen and also embryos were not strict enough.

The law did not require donor bulls to be tested. All that was required was that no Mycoplasma bovis had been found. But if you don’t look, then you can truthfully say you have no evidence of it being present.

Alternatively, if the infection has come through imported veterinary drugs, then things get somewhat murkier. But even then, unless the drugs were imported illegally, or used for an illegal purpose, then the farmers concerned are not to blame. Once again, the rules have been that you cannot import drugs known to come from an infected source, but there was no requirement to test.

This situation of not having to test arises from the fact that Mycoplasma bovis has always been regarded internationally as a minor disease. Also, whereas Mycoplasma bovis can hide from antibiotics when it is inside the animal – what is called ‘in vivo’ – it is more susceptible to the antibiotic drugs when present within semen or drugs. So, the usual response has been to treat the semen with antibiotics and then hope.

It is already known that Mycoplasma bovis genetic material has been found in imported frozen semen used by infected properties. This is stated in MPI’s Pathway Report. However, so far it has not been possible to culture this in the test tube, suggesting it has all been killed by the antibiotics. But it would only have taken one faulty batch for it to have slipped through.

Back in 2017, it was possible for MPI to say that there were no documented cases of Mycoplasma bovis being transmitted anywhere in the world through frozen semen. However, that is no longer the case, with a documented transfer in Finland reported in a paper within the Journal of Veterinary Microbiology. This paper has been circulated within some New Zealand veterinary and agricultural science groups, but it has not been acknowledged by MPI.

So far, New Zealand appears to be the only dairy-producing country to have raised the status of Mycoplasma bovis to that of a major disease. We may have been right to do this, but to date the rest of the world has not followed.  Rather, in all these other countries farmers manage the disease themselves. There have been some nasty outbreaks, but nearly all farmers have it under control as just a minor nuisance with appropriate management.

With hindsight, it is obvious that there was a contradiction between on one hand our New Zealand attitude that Mycoplasma bovis is important and on the other hand the biosecurity processes that we had in place. Our biosecurity arrangements were those of a country, like elsewhere in the world, who thought that the disease was just a nuisance that could be lived with.

There still remain other possibilities as to how Mycoplasma bovis got to New Zealand. For example, live animals are an obvious risk but there have been no animals imported since 2013. Prior to that there were imports from Australia, but the current evidence is that the New Zealand variant of the disease did not come from Australia – it has the wrong genetics for an obvious Australian source.

There is also the prospect that it came in via embryos. Over the last ten years there have been more than 5000 embryos imported to New Zealand. Most of these embryos probably went to the companies that sell semen. They would have used these embryos to produce new genetic material for their bull mating teams. There has been very little discussion about this as a potential source, including as a mechanism for Mycoplasma bovis getting into the semen.

Trying to see through the murk of MPI to get solid information is extremely difficult. Those of us who have a science background have found it impossible to date to get access to people with whom we can have an intelligent science-based conversation. The presentations to industry have been very superficial.

MPI points out repeatedly that it is advised by a Technical Advisory Group (TAG). MPI has recently provided the names of the 11 people in the group. Eight of them live overseas. I have tried to contact the NZ-based chair of the group but this person is also currently overseas on other business.

There are only two reports from the TAG that I can find. One was from a meeting in November 2017 and the latter was the report from a telephone hook-up in February 2018.  It seems that this group is very much part time and is called in sporadically. And they are themselves dependent on information provided by MPI. In their first report, they were politely but firmly critical of the quality of the information they were receiving.

It is clear that MPI does indeed have some specialist expertise within its team.  For example, the anonymous and redacted MPI Pathways Report was clearly written by someone who has lots of relevant expertise in terms of disease pathways. But that person is also operating from limited data.

MPI has currently advised the media that the reason it thinks Mycoplasma bovis has only been here for a maximum of two years is because of the genetic tracing and genetic time-clock. I have to question that judgement and I would love to hear the precise words of the scientist who supposedly made that call.  I know a little about genetic time-clocks and I suspect that there would have been all sorts of caveats that the scientist placed on that.

The key element of a genetic time-clock is the rate of mutations. We know that Mycoplasma bovis has great ability to evolve, but there is also evidence that this rate varies considerably in different environments.

One of the messages from the suspected botulism outbreak some five years ago was that scientific information, once transferred through multiple levels of non-scientist management, in that case within Fonterra, gets highly distorted. We need to be confident the same thing is not happening here.  The recent report on methamphetamine contamination here in New Zealand also illustrates what happens when non-scientists make an ‘inexplicable leap of logic’ (to quote Chief Government scientist Sir Peter Gluckman).

The question has to be asked as to why MPI is being so precious with the information they have at hand?

One suggestion I am getting is that MPI at senior levels has a culture of telling farmers no more than what is necessary, and MPI considers itself the arbiter of what farmers need to know. Or it could be, that with no science-trained biosecurity experts in their ten-person leadership team, and similarly at the next level of program management, that messages are getting muddled and omitted as they work their way through the chain. The third reason is that MPI lacks nimbleness. Like many bureaucracies, as the evidence changes, the non-scientist leaders struggle to stop defending a position and move quickly to solid ground.

It may also be that MPI is trying to protect its ability to take a court case against illegal actions. That is the only conclusion that can explain the ridiculous redaction of even mentioning ‘veterinary drugs’ as a potential category.

The problem for farm businesses – and there are well over 10,000 of these that are in risk management mode – is that it is impossible to put together sound plans without transparency of information.

In minimising risk, farmers have to make judgements as to where the greatest risks lie and act accordingly. Getting these assessments right is going to be crucial to the potential overall success of any national eradication program. Farmers and Government are in this together; it is not just Government.

In the current situation, there is a need for all of the semen companies to come forward and explain the measures that they are now taking for the coming season. Indeed, right now there are farmers using semen for next year’s autumn calving.

We need to know for each of those semen companies as to the measures they now have in place to minimise risk from their semen. This is not just for imported frozen semen, but also for fresh local semen where there are historical links back to imported embryos or semen, or where the bulls have been in contact with other bulls that have such a background. In fact, with the extent of the current outbreak, it needs to be for all of their bulls.

Although the Pathways Report from November 2017 suggests possible measures that can reduce the risks from semen, these are not yet legal requirements. So, all semen companies need to front up and tell us precisely what they are doing. I know that some companies have already changed their practices, but I do not know for all companies. The notion of ‘trust us’ is not good enough.

My own judgement right now is that the greatest risk to dairy farmers is from what are known as ‘service bulls’ which are used as follow up after two or three cycles of artificial insemination. Particularly risky is any bull that contains European-sourced genetics or which has been in contact in any way with such an animal. For graziers who run dairy support blocks, the greatest risk is that the calves coming onto their property will be infected.  Where female calves from different farms are run together by these graziers (as is common, particularly in the North Island), then there is a risk of subsequently transferring the organism back to all of the home farms.

About Keith Woodford

Keith Woodford is an independent consultant, based in New Zealand, who works internationally on agri-food systems and rural development projects. He holds honorary positions as Professor of Agri-Food Systems at Lincoln University, New Zealand, and as Senior Research Fellow at the Contemporary China Research Centre at Victoria University, Wellington.
This entry was posted in Agribusiness, Dairy, Mycoplasma bovis, Uncategorized. Bookmark the permalink.

12 Responses to Mycoplasma bovis: European semen is the likely source

  1. Rod McKenzie says:

    Great research and analysis, Keith

  2. Owen says:

    Keith, I have an interesting development I would like to discuss with you please regarding M. bovis. Could you text 0274424933 with a suitable ph no to call you and best time, please..

  3. Pingback: Rural round-up | Homepaddock

  4. farmerbraun says:

    If I knew the name of the North European semen company that is common to the five farms mentioned as infected, then I might not have a sleepless night.

  5. Matt Walker says:


    My apologies for being overly critical of you recently. Upon reflection you obviously have a tough job, and a lot of courage in being as outspokenly critical as you have been.

    Looking forward to reading this article presently.


  6. Matt Walker says:

    Beautiful analysis of the evidence, IMO. I think you’re possibly correct that no farmer is to blame…Although it is a well established scientific fact that animal agriculture is strongly implicated in the development and spread of infectious disease, particularly antibiotic resistant variants.

    I do feel somewhat sorry for them, though, because from what I have been told they are obligated under incredibly lengthy contracts to continue operations, even if they realize some time in that they want out. Please correct me if I am wrong about that, this is simply what I have been told by some in the industry.

    “Farmers and Government are in this together; it is not just Government”

    I think we are all in this together, the entire population.

    “It may also be that MPI is trying to protect its ability to take a court case against illegal actions. That is the only conclusion that can explain the ridiculous redaction of even mentioning ‘veterinary drugs’ as a potential category.”

    I think you may very well be right about that.

    “One suggestion I am getting is that MPI at senior levels has a culture of telling farmers no more than what is necessary, and MPI considers itself the arbiter of what farmers need to know. Or it could be, that with no science-trained biosecurity experts in their ten-person leadership team, and similarly at the next level of program management, that messages are getting muddled and omitted as they work their way through the chain. ”

    Excellent point, have been thinking along very similar lines myself recently.

    “Trying to see through the murk of MPI to get solid information is extremely difficult. Those of us who have a science background have found it impossible to date to get access to people with whom we can have an intelligent science-based conversation. The presentations to industry have been very superficial.”

    Precisely my experience. I’ve often tried writing to independent committee emails, only to be replied to by MPI staff. I have absolutely no way of knowing whether my communications were ever passed on to the committees that I assumed I was writing to.

    Excellent and courageous article. I am even a little worried for you, and if it comes down to it willing to stand with you if push comes to shove on this. For what it’s worth, you’ve earned my upmost respect.


  7. Stephen Averill says:

    I have great respect for kieth’s knowledge on agriculture but strongly disagree with his views on feeding calves non pasteurised milk and the risks associated with m bovis.Millions of calves will be born this spring and in the first hour after being born, will struggle to their feet and have a much needed feed of colostrum from their mother.Can you imagine every dairy farmer staying up night and day making sure their calves dont get a possible drink of m-bovis???Keith needs to go back to university and get a phd in PRACTICAL FARMING.Only then we will able to say he is true genius.Keep up your good work though Kieth,we need you.Regards Stephen Averill.

    • Keith Woodford says:

      I have a strict policy in regard to ad hominems at this site and this comment of yours went close. Let’s stick to the issues.
      I don’t think I made any mention in this particular post to calf milk, but regardless, I have on multiple occasions referred to ‘red’ (hospital cow) milk and the importance of this being pasteurised (or else thrown out).
      Let there be no doubt, it is the use of hospital milk that has led to the widespread dispersion of infected Southland calves here in NZ. In many parts of the world it is normal practice to pasteurise all milk that is fed to calves. On the larger farms in the USA it is also normal to separate the calf at time of birth and ensure all colostrum is pasteurised, but this is indeed scarcely feasible on smaller farms and with calves born in the paddock.
      If Mycoplasma bovis does become endemic in New Zealand then farmers will need to work out their own procedures. The common practice overseas on small and medium farms is that although calves do initially drink from their mothers, thereafter calves are held in separate pens to minimise cross contamination, and many farmers do then go the next step to only feed pasteurised milk to these calves.
      So, if Mycoplasma bovis does become endemic then life on NZ dairy farms will become somewhat different.
      Keith W

      • Stephen Averill says:

        Thanks for your reply Keith’ I have been milking 40 cows and feeding all the milk to 300 bull calves for the last 30 years.I also supplement the calves with 1.5 tonnes of milk powder and 5 tonnes of meal 16%.The calves are exposed to pasture at 10 days of age and have an average weaning weight of 115kgs.80 calves are sold on contract to the same farmers for many years,who much prefer them to milk powder calves and pay me a substantial premium.The remainder are taken through to yearlings and again sold to repeat clients.The cow herd is closed and all replacement heifers stay on farm.Have you any suggestions on what I should do? ps Going back to university is great as the first year is now free!! Thanks Stephen Averill

      • Keith Woodford says:

        My comments are somewhat generic as I don’t know where you are in NZ or where your calves come from.

        In terms of the source of your calves, the risk is lessened if they all come from one or two properties. They need to travel to your farm in isolation from other calves (no shared trucks) and not go to a saleyard.

        I think it is advisable to have on-sale contracts in place, and to have agreed with the subsequent purchasers as to where your animals are sourced and that this is approved by them, and that unless the property goes IP or RP or NOD then the animals will be purchased.

        I am aware of one Southland farmer with 1000 bulls who thought he had a contract in place with a corporate buyer but then got a solicitors letter wriggling out of the contract on the basis that the farmer could no longer guarantee good health of the animals. As I understand it, this property was a trace property but nothing came up positive. The problem is that there are now approximately 3000 trace properties in NZ and this is growing all the time.

        And I am aware of another large scale calf rearer who lost 600 calves (out of approximately 2500 calves) in 2016 from what now appears to be Mycoplasma bovis,. That farmer has had to sell the property.

        In this coming season, calf rearers without cast iron on-sales are the people at risk of getting caught. And often these are people who do not have the financial where-with-all to withstand such a blow. Calf rearers who have the capacity to take their animals right through to slaughter weight are at less risk. This is because the risk is not so much the disease but the risk of not being able to find a buyer.

        Keith W

  8. Stephen Averill says:

    Hi keith. I rang my brother in law in Buckinghamshire England this morning to get advice on managing m bovis.David has a 300 cow milking herd and has been successfully farming for 30 odd years and was runner up for England farmer of the year. A good person to talk to.He has had his challenges over the years with two confirmed cases of BSC in his herd and a fmd out break that was only 13 miles from his farm.Interestingly the fmd had no financial impact on his operation at all and was able to have his have his milk collected on a daily basis .The milk was then processed and exported to overseas markets!!A lot of people do not realize that fmd is non transmissible through milk! little wonder why Dairy NZ and Fonterra are quite happy to import palm kernel from an endemic fmd country and play Russian roulette with the NZ meat industry!! David said that the first time he had heard of M Bovis for a long time was when it was on the international news about what was happening in NZ.M Bovis ,like a lot of diseases is best managed by the farmers themselves rather than the government and tax payer.The disease is not anything as serious as what is being made out through the media.NZ is scoring a major own goal here and this senseless mass cull must stop now.We are destroying our international reputation by the day .I”m not sure about you going back to university though Keith,For a nominal fee you can ring me on 06 8760947 and give all the advise you need.Keep up the fight .Thanks Steve

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