Mycoplasma bovis update: important information for beef farmers

// Biosecurity

Beef + Lamb New Zealand, alongside DairyNZ and the Ministry for Primary Industries (MPI), is a partner in the Mycoplasma bovis (M. bovis) eradication programme.

image  of beef herd

In the latest update, the M. bovis programme has announced it has cleared a property and identified a new Active Confirmed Property.

Although this new case means there is currently only one farm known to be infected, we are halfway into a 10-year programme and it is likely more infected properties will be identified before eradication is achieved.

The new confirmed infected property neighbours a property with strong links to the Wakanui cluster in mid-Canterbury.

The programme is continuing to investigate the infection source and is working with the farmer to depopulate the property in a way which minimises disruption as much as possible.

As a result of the new infected property, the programme will also be tracing animal movements and other risk events. This will likely see an increase in the number of farms under movement restrictions while the programme ensures the risk of disease spread is mitigated.

Important advice for beef breeders

As we move into late autumn, beef breeders are planning mating for their herds, using either service bulls or artificial insemination. Bull buying season is underway, while many bull breeders (and some commercial breeders) will also be planning artificial insemination programmes for this spring.

Bull health

While an unlikely situation in the beef industry, bulls which have been in contact with infected cows and then moved to another herd are a risk for the spread of M. bovis. All bulls should arrive on-farm properly identified and with their movement history details.

Make sure you let the vendor or agent know that you expect this. Hold bulls separately from the main herd for at least seven days to assess their health status for M. bovis and other diseases, and to complete treatments like drenching.

If you have any concerns about the bull's health, contact your veterinarian before you mix them with the herd.

Artificial insemination precautions

The risk of transmission via imported semen is considered very low, especially after the introduction of a new import health standard last year, but very low risk is not the same as no risk. As a precaution, ask your semen supplier for advice on what testing the bull and/or semen has been subjected to.

While MPI assesses the M. bovis transmission risk associated with bovine semen imported before April 2022 as very low due to required antibiotic treatments, bovine semen imported after that date is subject to improved antibiotic treatments or PCR testing for M. bovis.

As a precautionary measure, the programme will undertake more testing of older imported semen to improve the understanding and mitigate some of the risk presented by it. Breeders considering purchasing semen imported prior to April 2022 should contact their breeding centre to ensure that the semen has undergone appropriate testing. Breeders with stores of semen held on-farm or in centres should contact the importer to see if the semen is within scope for MPI testing.

Why is this testing being required now?

In September 2022, a new strain of M. bovis was identified on a dairy farm in mid-Canterbury, which has now been depopulated, cleaned, disinfected, and all movement restrictions have been lifted. All animal and risk events on and off this farm have been followed up and no further infection has been identified. Imported bovine semen is considered the most plausible source of introduction of this new strain.

The M. bovis programme‘s extensive bulk milk testing, beef and drystock, and network surveillance gives us confidence that M. bovis is not widespread in New Zealand. More biosecurity advice relating to autumn is available on the M. bovis website: Autumn seasonal calendar.