Minimising the bull buying disease risk | Beef + Lamb New Zealand
M Bovis

Minimising the bull buying disease risk

Bull selling season is in full swing and farmers may be nervous about buying beef bulls in light of the Mycoplasma bovis outbreak.
Wednesday, 30 May 2018

Paul McCauley, Beef + Lamb New Zealand’s Biosecurity liaison says while bulls are considered a low risk stock class, there are measures farmers can take to reduce the risk of bringing Mp. bovis onto their properties.

These include determining the health history of the source herd, ensuring the bulls are transported in clean trucks and quarantining the bulls for as long as possible from your other stock. It is highly recommended that accurate records are kept detailing how new bulls have been kept separate from home stock.

If the bulls are of dairy origin and Mp.bovis  has not been detected in the herd’s bulk milk and discard milk tests, then the risk of these bulls spreading infection is lower than from a property where test results are unavailable.

If the bulls are from a beef property and Mp. bovis test results are unavailable, then the best indicator of the level of risk from these bulls remains the health status of the herd(s) the bulls have been running with – pay particular attention to the herd's levels of mastitis and lameness.

A pre-purchase check list compiled by the Ministry for Primary Industries is available at:

Testing for Mp. bovis

  • Because infected animals shed bacteria intermittently, testing will not completely exclude the possibility of infection.
  • Three or more negative tests from the same bulls from the same property will provide some confidence that the farm is Mp. bovis free, depending upon how the testing was undertaken.
  • Testing can be prolonged, can lead to inconclusive results and the possibility of false positive or false negative results. We advise farmers to consult their vet if strongly motivated to undertake testing.

Determine the health status of the herd and individual bulls

  • Ask the stud breeder if there have been any prolonged animal health issues in the herd or individual animals.
  • Ask whether the bulls remained on the one property in their lifetime and whether have they been exposed to any trading cattle or dairy grazing animals?


Ensure any bulls purchased are transported in clean trucks.  Ideally, trucks should be hosed down between herds and again at the end of the day.

Do the paper work

Ensure all animals are ear-tagged, that movements are registered with NAIT and that you receive an Animal Status Declaration (ASD) form with every group of animals purchased.


Keep purchased bulls away from other cattle already on your property for as long as possible and record how this was quarantine process was implemented.

Other livestock

Mp. bovis is a cattle-specific disease. There is no risk of direct transmission of disease from other species of livestock.

Follow the guidelines

Mp. bovis is mainly spread by direct contact with infected cattle or by feeding raw milk.  According to information from Ministry for Primary Industries, Mp. bovis is not thought to be transmitted in urine and faeces and is not windborne or spread in running water.

It is a disease that moves relatively slowly between farms and other animals cannot transmit it.

Farmers should consider standard biosecurity advice to prevent their stock coming into nose-to-nose contact with neighbour’s cattle. This could be achieved by creating boundary fence buffer zones using electric out-riggers or a separate electric fence two metres back from the boundary.

B+LNZ urges farmers to require cleaning and disinfection of footwear, protective clothing and equipment of visitors working with their cattle.

Find out more

For more information, visit: