If you’ve recently received a new herd of calves and, up to a month later, they are showing signs of respiratory disease, then you may have mycoplasma bovis present in your cattle.

Mycoplasma bovis is the most prevalent pathogen and invasive cause of mycoplasma mastitis in dairy cattle and can cause a wide range of issues in cows such as pneumonia or arthritis. Mycoplasma bovis bacteria is contagious and affects young or mature animals and subsequently, their milk productivity. Early detection is critical.

Bacteria such as Mycoplasma bovis can greatly affect your cattle’s health, growth rates, milk production and profit margins, so it’s essential to be aware of these diseases, the causes, the symptoms, and how to go about preventing and treating them.

What is Mycoplasma Bovis?

Mycoplasma bovis is a bacterial organism that causes a range of different problems in cows such as treatment-resistant mastitis, pneumonia, arthritis, or late-term abortions. It is a major, but often overlooked, pathogen that is considered one of the most important causes of calf pneumonia worldwide.

The bacteria can be dormant in animals with no symptoms whatsoever. However, the stress to a cow during transportation, calving, drying off, or extreme weather can trigger the bacteria to be released in their milk and nasal secretions. The secretions can infect other cows who may likely present symptoms or also become carriers of the bacteria.

This pathogen attaches itself to mucosal surfaces, then invades tissue and frees toxins that can cause severe cellular damage. It can then move through the bloodstream to other tissues like joints causing arthritis and lameness. Additionally, Mycoplasma can suppress an animal’s immune system and can increase the severity of disease caused by other pathogens.

How is Mycoplasma Bovis Diagnosed?

Diagnosis of M. bovis can be made by serology or PCR (polymerase chain reaction) testing by taking culture from individual animals, or by bulk milk serology or PCR for the identification of infected herds. ELISA testing can be used for serology on individual animals, but is better used to identify seroconversion or high titres in groups of animals.

The PCR test works by capturing DNA from a virus or bacteria and amplifying it until it can be identified. This test is conducted when the animal is shedding, as this is when it is best able to detect Mycoplasma bovis. Infected cattle will always shed when showing clinical signs of illness, but they may also shed without showing any other symptoms.
Where did Mycoplasma bovis come from?

Mycoplasma bovis arrived in New Zealand from late 2015 to early 2016. It is transmitted between cattle by close contact between animals and in their bodily fluids. For example, nasal secretions, mucus, and milking equipment can spread it.

Calves can be infected by drinking milk from infected cows.

Since 2017 262 farms were confirmed as having it, the latest figures show only 11 farms are actively infected. Although M bovis is still a concern across dairy cow farms, the ministry of primary industries is confident that New Zealand is working hard to eliminate this infection.

Any animals that come onto your farm are a potential source of disease for your herd. Similarly, if you send any of your cattle away for grazing, they can be at risk from unknown exposure.

What are the Symptoms of Mycoplasma Bovis?

There are several Mycoplasma species, but Mycoplasma bovis is the most problematic in cattle. Overseas research tells us that half of the cattle with normal lungs carry M. bovis, but this pathogen is found in a whopping 98% of cattle with chronic pneumonia.

Respiratory diseases caused by Mycoplasma bovis typically portray fairly mild symptoms. A cattle’s body temperature is more likely to be close to normal, but they may also present with mild fever. There would likely be a clear and runny nasal discharge.

Symptoms to look out for in your cattle if you’re worried that Mycoplasma is present include increased respiration, as faster breathing is often a sign of illness. Some calves may present with a harsh hacking cough, discharge from the nose, and watery eyes, fever, and decreased appetite. Even arthritis, tendon inflammation, or lameness that appears around a week after pneumonia symptoms arise, are all signs you may have Mycoplasma bovis present in your herd.

Cattle infected with M. bovis related bovine respiratory disease typically show signs of pneumonia three to four weeks after arrival at a farm and will not respond well to treatment. A couple of weeks later, some of these pneumonia cases will develop symptoms of arthritis and some cattle will die from the infection three to six weeks after arrival.

Does Mycoplasma Go Away?

Infections related to Mycoplasma bovis can go away on their own without any medical intervention, though this generally happens when the symptoms are milder. If your cattle are experiencing severe symptoms, a Mycoplasma infection can be treated with antibiotics like azithromycin, clarithromycin, or erythromycin with proper consultation with your veterinarian.

Once established, a Mycoplasma infection can spread quickly throughout your herd, so early intervention is critical. However, if the symptoms are mild, this can give farmers a false sense of security and the severity of the infection can escalate quickly. By this time, the outbreak of infection can have a devastating impact. Infections can affect the cows’ ability to gain the optimal amount of weight, affect their milk production, and postpone their time to market.

Prevention and Management

Investing in indoor farming practices enables farmers and their teams to monitor health issues and feed intake and encourage a well balanced diet for individual cows. By controlling the feed per cow with a reliable, quality supply of feed, you can help maintain each and every dairy cow’s optimum size, health, and milk yield. Should they arise, any changes in their health can be easily identified, allowing you to quickly address them and minimize food wastage.

By being aware of the symptoms early on and knowing how to treat them effectively, it can help prevent further losses and costs to the farm. However, experience has shown that even heifers that are treated early on for pneumonia produce significantly less milk throughout their lifetime than heifers who have never had the disease.

Mycoplasma bovis is managed on farms throughout the world using good biosecurity practices, and it is recommended to set up a biosecurity plan for your farm. Be careful when selecting new cattle stocks and breeding bulls and follow good practices to keep your cattle herds healthy.

As the bacteria is spread from animal to animal, restricting the movement of your cattle is the best method to prevent contamination. Farm equipment such as milking apparatuses and artificial insemination instruments play a big part in the transmission of the bacteria. For this reason, ensuring your equipment is thoroughly cleaned on a regular basis will help prevent the spread.

The Biosecurity Act strictly requires comprehensive cleaning and disinfecting before leaving any infected farms.