At the time of writing Mycoplasma has been confirmed on 39 farms, the most recent being a farm near Cambridge in the Waikato. It seems it will only be a matter of time before it is found in the BOP.
Mycoplasma bovis is a bacterium that causes a range of diseases in cattle that don’t respond to treatment. It is highly undesirable to have it in NZ or on your farm because of its cost in terms of productivity and culling. However to be kept in perspective it is not the end of the world and is not a reason to give up on farming. Most countries including Australia have Mycoplasma and farmers in those countries have learnt to live with it. On the plus side is that it is a relatively slow moving disease and there is no danger to humans and no risk to humans from consuming meat or milk products from infected animals.
In adult cattle it causes:
· Non responsive mastitis usually involving multiple quarters. The affected quarters are swollen (rubbery) but not hot or painful and will rapidly dry off. The cow does not get sick.
· Abortions or early small calves.
· Swollen joints that are painful and hot and cause marked lameness.
· Severe pneumonia starting with a hacking cough
· Ear infections starting with a droopy ear & sometimes head tilt
· Conjunctivitis leading to sticky white eyes
· Swollen legs/joints that are painful & hot
All these can be symptoms of other common diseases but the key is that response to treatment is poor or several animals are affected or individual animals have more than one sign. If suspicious ring us as soon as possible.
A big part of the problem with Mycoplasma is that it is a wretched disease to diagnose. The immune response is variable, and the shedding of the organism is affected by stress factors such as pregnancy, lactation, transport etc. This means that even a perfect test will miss some carrier animals because they are simply not shedding at the time of testing. To be reasonably sure a herd is negative requires several tests at intervals. Added to this is that some tests also have high false positives.
· For animals showing symptoms then a sample of the relative exudate i.e. Milk, joint fluid etc will be diagnostic.
· For milking herds several bulk samples over time will determine herd status.
· For dry stock there is no easy answer. Nasopharyngeal swabs are the best bet but are difficult to do and probably have to be repeated to give a true indication of herd status.
Mycoplasma is mainly spread by direct contact between infected animals. It potentially can also be spread on equipment that has been used on infected animals eg milking machines, AI and veterinary procedures. It is spread through bodily fluids but not as far as it is known through urine or faeces. It is not windborne or spread through rivers and streams.
Prevention is focused on farm biosecurity and cleaning & disinfection. For detailed notes visit the MPI and DairyNZ websites.
· Where practical limit cattle movements onto your farm. Mycoplasma can be present in apparently healthy animals and there is currently no commercially available pre-movement test that can be applied to detect infection.
· Create boundary buffer zones to prevent contact with neighbours stock. Do not graze paddocks at the same time as neighbours stock is next door.
· Do not buy in or lease stock. If you do ask questions about the farms stock health and history. A supplier farm that breeds its own stock will be safer than someone who buys stock from elsewhere and grows it.
· If you have to graze out stock check on the biosecurity of the grazier and who else grazes there and what their history is. Talk to your grazier about not mixing mobs and avoiding nose-to-nose contact with other stock. Insist your carrier transfers your stock in a clean truck by themselves.
· Keep all newly arrived stock on farm separate for at least 7 days. Monitor them for signs of disease and if in doubt call a vet.
· Make sure animals have NAIT tags and all sending and receiving movements are sent to the NAIT sysyem
· Manage access on farm. This includes limiting people who come on to farm and to where. It also includes equipment and stock trucks.
· Have a suitable cleaning and disinfectant protocol for boots, equipment and visitors. Equipment, boots etc have to be clean before they can be disinfected. Suitable disinfectants include 1% Virkon, 0.2% citric acid and Trigene.
Managing the disease:
There has not been a lot come out about managing Mycoplasma because the hope is we will eradicate it. However overseas experience suggests that stress plays a huge part in managing the disease. Key points are:
· Ensure all animals are kept healthy and in good condition.
· Be proactive with diseases that can be prevented e.g. BVD, worms, facial eczema, trace elements, mastitis etc etc
· Minimise stress e.g. Feed, transport, housing, time walking, overcrowding, yarding time etc.
· Identify and cull clinicals ASAP to minimise spread
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Local farmers, associated rural communities and Te Puke town people have supported Te Puke Vet Centre for over 50 years. During those years scores of receptionists, nurses and vets have lived and enjoyed the benefits of this great town and area. It is very important for Te Puke Vets that we are strongly integrated with the local community and as part of that we are proud to support many local schools, sports clubs, service organisations and community events.