There are 13 species of Mycoplasma that can affect cattle, however, some are more aggressive to their host than others. The most significant in the UK appears to be Mycoplasma bovis.
Read more: Disease Focus On Mycoplasma
The disease was only discovered in the 1960’s and first found in the UK in the 1970’s. It is thought to be involved in a third to a quarter of all pneumonia cases in Britain. Once in a herd, it is a disease that is notoriously difficult to diagnose and control let alone eradicate.
Clinical signs
The most common clinical sign of mycoplasma in the UK is pneumonia, sometimes as a sole agent but more commonly in combination with other viral, bacterial and parasitic agents. This can occur at any age in beef or dairy cattle, sometimes with poor response to treatment and there are cases of relapse commonly reported. Head tilt and ear drop are symptoms seen particularly in younger animals. In lactating animals, it can present as mastitis, though often as an incidental finding in cases of poor response to treatment. Arthritis leading to joint swellings can present. Less frequent symptoms include inflammation of the eye, meningitis, infertility and abortion.
Control
Due to mycoplasma’s lack of a cell wall, there are only a limited number of antibiotics that are effective against the disease. Furthermore, because of its broad genetic variability, there is growing resistance to some of those antibiotics and therefore it is no longer considered prudent for some of those antibiotics to be used in anything other than in human medicine. Certain dairy processing firms are starting to look at reducing the use of these antibiotics and ultimately preventing their use altogether. If mycoplasma is present on-farm, a non-antibiotic approach to control should be a target in the future, for example, thorough steam clean and disinfection of accommodation between groups of calves in an all-in all-out system in each shed is important to reduce transmission.
Diagnosis
Diagnosis is attained:
- at the time of active infection via fluid samples taken directly from the lungs or swabs from the back of the nose
- from samples at post mortem
- from blood samples at least four weeks after clinical signs presented
Speak to your veterinary surgeon to work out the best method to determine the presence of the disease on your farm.
Prevention
The most effective way to prevent any disease from entering a herd is to run a closed herd (that means preventing contact of stock with neighbouring animals, not buying in stock or even bringing in a bull). The most effective method of preventing disease in a pre-weaned calf is to ensure adequate colostrum consumption within its first 24 hours of life. Other recommended methods include only feeding pasteurised colostrum/whole milk to calves and improving housing/ventilation. Improving unhygienic milk feeding practices is also recommended and automatic feeding systems have been implicated in the disease spread. There are indications that calves may be infected whilst in the dam which could mean colostrum pasteurisation is futile.
Vaccine
Currently, there are no vaccines that are licensed in the UK, however, there are a couple of options in terms of acquiring a vaccine. There are some companies that can create autogenous vaccines specific to the mycoplasma on the farm. Alternatively, a new vaccine created in USA has been granted access for use in the UK through a special import certificate (SIC) scheme. It is a one-shot vaccine covering three strains of the disease and will cover the animal for a year.
In the case of protecting youngstock from pneumonia after weaning, they should be vaccinated at 60 days of age, however, if pneumonia occurs prior to weaning, it is recommended that the dam is vaccinated at drying off (it has a 60 day milk withhold). This will give the best chance of creating a good immune response to the disease for the cow and, therefore, a better chance of creating colostrum that will adequately protect the calf for the first few weeks of its life. Later, this should be followed up with the vaccine for the calf at 28-35 days of age which will allow the calf’s own immune system to build its own active immunity.
This course of action will protect the calf through its most vulnerable period to pneumonia by reducing mortality, lung damage, antibiotic use and risk of antibiotic resistance; therefore, increasing growth rate and ultimately giving animals a better chance of entering the milking herd at two years of age. Best results will be seen where other causes of pneumonia are either controlled or not present. The author is aware of one farmer who has seen an increase in growth rate of 25% since starting the use of this vaccine. If in any doubt then speak to your veterinary surgeon for advice.
