M. bovis can cause serious health problems in cattle
M. bovis is a bacterial disease that creates an animal welfare and productivity issue. It 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.
How M. bovis is spread
Infected animals may shed (release) bacteria in milk, colostrum, nasal secretions, or semen, enabling the bacteria to spread to other cattle. Cattle can be infected with M. bovis without showing any signs of infection.
M. bovis typically spreads between cattle when they have close contact, such as when they:
- mix together in a paddock, pen, milking shed, or calf shed
- walk down a road where nose-to-nose contact is possible with cattle held in paddocks adjacent to the road
- stray across boundaries via break-ins or break-outs
- are calves and are fed milk or colostrum from infected cows.
It can also spread via the equipment used on infected cows as part of the milking process.
M. bovis most commonly spreads between properties when M. bovis-infected cattle are introduced into a healthy (previously uninfected) herd.
M. bovis in the environment
M. bovis is fragile in the environment. It only survives for very short times when exposed to heat, drying, and UV light. It can survive longer in cool, moist, and dark environments.
M. bovis is unlikely to survive for long periods in grazing blocks or areas used in baleage and silage production.
The risk of the disease spreading via organic material such as soil, effluent, or feed types (baleage and silage) is also extremely low.
Look out for signs and report M. bovis
Signs in cattle include:
- unusual mastitis in cows that doesn't respond to treatment
- reproductive losses
- high numbers of calf deaths.
Signs in calves include:
- severe pneumonia, starting as a hacking cough
- ear infections – the first sign typically being one droopy ear, progressing to ear discharges, and in some cases a head tilt
Not all infected animals display symptoms, but they can still spread M. bovis to other cattle through close contact.
M. bovis mainly affects cattle and has little effect on other production animals. It does not affect horses and other pets.
Look out for signs of M. bovis and report any signs to:
- your veterinarian
- MPI on freephone 0800 80 99 66.
Six ways farmers can help eradicate M. bovis
- Run cattle in management units that don't mix. Minimise introductions and keep any introductions low risk (for example, keep mobs separate for their duration on grazing blocks).
- Secure boundaries through fencing and due diligence. Make sure nose-to-nose contact is not possible between cattle held on neighbouring properties.
- Keep NAIT (National Animal Identification and Tracing) updated. NAIT is a legal requirement and key to good biosecurity, as it makes it easier and faster to trace animals.
- Ensure any equipment or biological products you bring on-farm are M. bovis-free. Make sure equipment (such as borrowed milk feeding equipment) is clean and disinfected prior to use on your property.
- Avoid trading colostrum and milk – the lowest risk for spread of M. bovis is calf milk replacer.
- Make sure donor bulls have been tested for M. bovis and if you use artificial insemination, ask your semen supplier what assurance they can provide that the semen is free of M. bovis.
These good on-farm biosecurity practices will help limit the spread of other diseases as well.