Mycoplasma bovis (M. bovis) is a bacteria that can cause serious health conditions in cattle, including mastitis (udder infection), pneumonia, arthritis, and ill-thrift in calves. Less commonly it can cause progressive neurological disease in calves, conjunctivitis, and reproductive losses.
The infection is:
Cattle can be infected with M. bovis without showing any signs of disease. During times of stress such as during calving, early lactation, drying-off, transport or exposure to extreme weather conditions, infected cattle are more likely to show signs of infection.
Infected animals may ‘shed’ (release) bacteria in milk and/or nasal secretions, enabling the bacteria to spread to other cattle.
M. bovis was detected in New Zealand for the first time in 2017.
A law change in 2018 means M. bovis is now listed as an Unwanted Organism under the Biosecurity Act 1993.
M. bovis typically spreads between cattle when they are in close contact for a prolonged period of time (i.e. when they are together in a paddock, pen, or milking shed). Usually, infection spreads between farms when infected cattle are brought into a previously uninfected herd.
M. bovis can also be spread to calves that are fed milk from infected cows.
The bacteria may be spread via genetic material containing the bacteria such as semen, but this means of spread is extremely rare compared to spread via the movement of live cattle and milk.
M. bovis is fragile in the environment – it only survives for very short times when exposed to heat, drying and UV light, but can survive longer in cool, moist and dark environments.
Equipment used as part of the milking process has been linked to the spread of infection between cattle on individual farms.
M. bovis is unlikely to survive in grazing areas and areas used in baleage and silage production. The ensiling process creates an acidic environment (approx. pH 4.5) where M. bovis bacteria are unlikely to survive. Silage and baleage pose an extremely low risk of spreading M. bovis and may be fed as usual or transferred off the farm for sale.
The risk of M. bovis spreading via organic material such as soil, effluent, and other feed types is also extremely low.
M. bovis can have a devastating effect on farm production and animal welfare. However M. bovis does not infect humans and is not a food safety risk.
It’s not considered a disease of relevance to trade by the World Organisation for Animal Health (the OIE) and internationally, there are no regulatory restrictions for meat and dairy products due to M. bovis. Infection is common in many food producing nations, and where infected cattle aren’t showing signs of infection they are processed for human consumption.
In New Zealand, our laws mean any animals that are very sick, severely injured or have medications in their bodies are not processed for human consumption. All animals are also examined after slaughter to ensure the meat is safe and suitable for consumption.
You should contact your vet and MPI as soon as possible if:
Making sure good biosecurity practices are in place on your farm, reduces the risk of M. bovis.