About Mycoplasma bovis (M. bovis)

Range of symptoms can indicate M. bovis infection

M. bovis is a bacterium that can cause serious health conditions in cattle. It has little effect on other animals, and doesn’t affect horses, other pets or humans.

Signs in cattle include:

• unusual mastitis in cows that doesn't respond to treatment
• reproductive losses
• pneumonia
• arthritis
• conjunctivitis 
• lameness and swollen joints. 

Signs in calves include: 

• high numbers of deaths
• severe pneumonia, starting as a hacking cough
• droopy ears
• ear discharge
• head tilt
• abnormal gait
• fading calves
• arthritis
• conjunctivitis
• lameness and swollen joints. 

Not all infected animals display symptoms, but they can still spread M. bovis to other cattle. 

The M. bovis bacteria can hide from the immune system. This makes it hard for cattle to fight off infection, as well as making it difficult to diagnose in an individual animal. 

Treatment with antibiotics is usually unsuccessful. 

M. bovis can spread in different ways

M. bovis can spread when infected animals shed (release) bacteria in: 

• milk
• colostrum (first milk produced by a cow after giving birth)
• nasal secretions 
• semen. 

The disease typically transfers between cattle when they drink milk or colostrum from infected cows or when they are close together — for example, when they: 

• mix in a paddock, pen, milking shed or calf shed
• walk down a road where nose-to-nose contact is possible with cattle in nearby paddocks
• stray across boundaries.

M. bovis most often spreads between properties when infected cattle join a healthy herd. 

It can also spread through the equipment used on infected cows during the milking process. 

M. bovis is fragile in the environment

M. bovis bacteria only survive for very short times when exposed to heat, dry conditions or UV light. They can survive longer in cool, moist, dark environments.

M. bovis is unlikely to:

• survive for long periods in grazing blocks or areas used in baleage and silage production
• spread through organic material such as soil, effluent or feed types (baleage and silage).

No risk to food safety or international trade

The M. bovis bacterium isn’t a risk to human health and it’s safe to eat meat and drink milk from infected cattle. 

M. bovis is not considered a disease of relevance to trade by the World Organisation for Animal Health and internationally. There are no regulatory restrictions for meat and dairy products due to M. bovis.