Mycoplasma Bovis
Understanding Mycoplasma bovis: An Overview
Mycoplasma bovis is a bacteria which can lead to a range of diseases in cattle, including mastitis, arthritis, ear infections (otitis) and pneumonia. The organism is regarded as an “atypical” bacteria, due to the lack of a cell wall which makes it more
difficult to treat using antibiotics.
Transmission and Persistence in Cattle
The bacteria tends to persist for varying periods of time in infected animals, and shedding can be intermittent. Apparently health animals can carry the organism as “commensals” or bacteria which live on internal tissue surfaces such as the respiratory tract. Infection can be introduced into previously uninfected herds through the introduction of one of these carrier animals.
These animals can carry the infection in the tonsils/ respiratory tract/ as ear infections or mastitis. Infected animals can pass the infection onto other animals via secretions such as nasal secretions, aerosols or in the milking parlour via milk at milking time. Outbreaks of disease tends to be more severe in herds which have no previous exposure. Replacement animals can be screened using the antibody elisa test , although the absence of antibodies does not always mean that the animal is free from infection.
Pneumonia and Arthritis: Key Health Concerns
Mycoplasma bovis can cause pneumonia, either alone or as part of a mixed infection with other viruses. Infection of the lungs with mycoplasma bovis results in the development of chronic abscesses which are resistant to treatment. Mycoplasma bovis may be accompanied with arthritis in one or more joints, or arthritis may occur without pneumonia.
Mycoplasma is also associated with highly contagious mastitis, resulting in very high Somatic Cell counts, and often visually abnormal milk which can be purulent (but odourless) . It can also be present sub clinically with little or no visible changes in milk but resulting in elevated SCC.
Impact on Mastitis and Milk Quality
Once an active infection becomes established in a herd secretions from infected joints/ aerosols and droplets from the respiratory tract and milk samples can be infectious. It is thought that transfer via milk is one of the most common sources of mycoplasma related ear infections in calves.
Detection and Monitoring Strategies
Use of PCR testing to monitor the bulk tank for the presence of the mycoplasma bovis organism is a useful monitoring tool. Testing of pools of milk samples (5 individual samples) taken from cows during milking can be used to identify cows which are shedding Mycoplasma bovis. Control measures for mycoplasma mastitis focus on identifying infected carriers and culling of same, or in larger herds, establishment of two groups, an “infected” and “clean” group. Some options are available for the use of commercial or autogenous vaccines in infected herds. In the case of autogenous vaccines, a pure culture from the herd is required to create “seed material” for the vaccine. Treatment in mastitic/ arthritic cows is unrewarding and not generally recommended, apart from perhaps the use of analgesics to control pain and inflammation.
Seeking Further Information and Support
For more information on any of the above contact FarmLab Diagnostics
