Protecting Dairy Farms: Lessons from the Bird Flu Outbreak
The recent H5 avian influenza outbreak in US dairy cattle serves as a stark reminder of the global health risks posed by bird flu and the need for Australian farmers to stay vigilant. This highly contagious virus, first detected in US dairy cattle in 2024, has caused significant illness and production losses, as well as sickness among dairy farm workers. Since then, it has spread across 18 US states, affecting over 1000 dairy herds.
The unprecedented transmission of the virus from birds to dairy cows has provided valuable insights into the disease's behavior in cattle and its potential spread within dairy systems. While Australia remains free from this strain of H5 bird flu, and the risk to the Australian dairy industry is currently assessed as low, the experience of other countries offers crucial lessons for preparedness.
In response to the evolving global situation, the Australian Federal Government, in collaboration with states, territories, and the industry, has strengthened national preparedness. This includes enhanced surveillance, improved coordination between animal, wildlife, and human health agencies, and targeted investments. The Department of Agriculture, Fisheries, and Forestry, supported by Dairy Australia, commissioned an independent risk assessment to understand the potential impact of a spillover event under Australian conditions.
The assessment revealed that the risk of H5 bird flu entering the Australian dairy herd is low, and even if it does, the risk of spread between farms is also low. This lower risk can be attributed to factors such as lower farm density and fewer routine cattle movements. Australia's proactive approach, coupled with its unique circumstances, provides a distinct advantage.
Dairy farmers in Australia should remain vigilant and be aware of the clinical signs of H5 bird flu. In infected US herds, common signs included a sudden drop in milk production, thick milk resembling severe mastitis, fever, and lethargy. While mortality rates in cattle have been low, morbidity has been high, with many cows requiring weeks or months to recover their milk production.
To prevent the introduction and spread of H5 bird flu, Australian dairy farmers can implement several simple measures:
- Animal Movements: Quarantine and observe newly purchased animals or those moving between farms before they join the milking herd. US authorities have also introduced testing protocols for cattle movements and bulk-milk screening.
- Milking Hygiene: Maintain strict hygiene practices when milking affected or suspected cows, milking them last or separately when possible, to limit the spread through liners and cups. Proper handling of mastitic milk, cleaning of equipment, and consistent teat preparation are essential.
- Reducing Milk Aerosols: Minimize the creation of fine aerosols by using lower-pressure wash-down methods and reducing milk spills. High-pressure hosing can create fine aerosols, so lower-pressure methods are recommended.
- People Protection: Good biosecurity practices include wearing gloves during milking and handling milk or sick animals, washing hands after glove removal, and managing contaminated work clothing. Encouraging seasonal flu vaccination can help prevent dual infections.
- Surveillance and Reporting: Farmers should be vigilant and report unusual clusters of mastitis-like illnesses, sudden production drops, or unexplained bird deaths to receive early advice.
Preparation and preparedness are key to safeguarding the Australian dairy industry. A well-maintained, up-to-date biosecurity plan remains the foundation of effective prevention and control measures.
As Andy Hancock from Dairy Australia emphasizes, "Preparation comes back to fundamentals."
Stay informed, stay prepared, and together, we can protect our dairy farms from potential threats.
