Mycoplasma in Livestock Production: Focus on Ruminants

By DVM Miltos Ioannou

Mycoplasma species are a genus of bacteria responsible for significant economic losses in livestock farming worldwide. These pathogens not only cause direct clinical illness in animals but also compromise the immune system, increasing susceptibility to other infections.

The Impact of Mycoplasma on Livestock Health and Farm Profitability

The severity of Mycoplasma-related diseases in livestock is influenced by factors such as poor management practices (e.g., stress, overcrowding, inadequate housing) and concurrent bacterial or viral infections. Mycoplasma organisms lack a cell wall, making them naturally resistant to β-lactam antibiotics and complicating treatment options.

Furthermore, their ability to evade the immune system, invade host cells, and form biofilms enables them to establish chronic and persistent infections in herds.

Mycoplasma bovis in Cattle

Clinical Signs and Economic Impact

Mycoplasma bovis in cattle, both dairy and beef, is a major concern in livestock production. It often goes undetected in early stages and responds poorly to common antibiotics. This has contributed to substantial financial losses, with estimates exceeding €576 million annually.

The most prominent clinical signs of M. bovis infection include:

• Chronic respiratory disease and pneumonia

• Mastitis (udder infection)

• Arthritis and joint swelling

These symptoms can lead to irreversible lung damage, decreased milk yield, and general productivity loss in affected cattle.

Transmission and Risk Factors

M. bovis typically enters through the upper respiratory tract and is shed via nasal secretions. Calves can become infected through:

• Ingestion of contaminated colostrum or milk

• Contact with animals suffering from Mycoplasma bovis mastitis

• Exposure to stress factors like multi-age housing, transport, and transition phases

  
  

Prevention Strategies

Effective biosecurity and management are critical to preventing the spread of M. bovis:

• Ensure proper ventilation and hygiene

• Avoid overcrowding

• Implement colostrum management protocols

• Introduce a vaccination program specific to M. bovis

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Treatment Challenges

Treatment options are limited and must be carefully selected. Antibiotics with approved usage for M. bovis infections include:

• Macrolides (e.g., Tulathromycin) – preferred due to prolonged action

• Fluoroquinolones (e.g., Enrofloxacin)

However, due to antibiotic resistance concerns, early intervention is essential.

Contagious Agalactia in Sheep and Goats

Causative Agents and Transmission

Contagious agalactia is primarily caused by Mycoplasma agalactiae, with other species such as M. mycoides capri, M. capricolum capricolum, and M. putrefaciens involved depending on the region.

Transmission occurs via:

• Aerosols from infected animals

• Contaminated milking equipment

• Colostrum or milk during suckling

Clinical Presentation

Common symptoms of contagious agalactia include:

• Fever

• Mastitis (sudden drop in milk yield and quality)

• Conjunctivitis

• Arthritis

• In severe cases, death or reproductive failure (e.g., abortions)

The disease often becomes chronic, and even treated animals may remain lifelong carriers, posing a persistent risk to the herd.

Treatment and Control

Therapeutic options include:

• Fluoroquinolones

• Macrolides

• Tetracyclines

• Lincosamides

While clinical improvement is possible, particularly with early treatment, the risk of carrier animals remains.

In endemic areas, inactivated vaccines are used with varying success. However, vaccination alone is not sufficient without rigorous herd management.

Preventive Measures

To reduce infection risk:

• Improve milking hygiene and equipment sanitation

• Pasteurize milk or colostrum before feeding to young animals

• Avoid introducing replacement animals without prior Mycoplasma testing

• Use artificial insemination to limit genetic transmission risk

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Conclusion

Controlling mycoplasma infections in livestock is a multifaceted challenge that requires proactive management, early detection, and strategic use of medication and vaccination. By improving herd health protocols and biosecurity measures, livestock producers can mitigate the long-term impact of diseases like Mycoplasma bovis and contagious agalactia.