The use of high expansion nitrogen foam has emerged as a potentially effective method for culling poultry, offering notable welfare advantages compared to traditional methods. According to a report by the UK’s Animal Welfare Committee (AWC), this method should be considered for immediate implementation in disease control scenarios.
Overview of Current Culling Methods
Currently, the Animal and Plant Health Agency (APHA) employs various methods to humanely cull birds on infected premises. These methods include mechanical percussive devices, containerized gassing units, and whole-house gassing. Whole-house gassing with carbon dioxide has seen increased use due to its effectiveness and rapid deployment capability. However, its efficiency is limited in certain scenarios, such as when poultry houses are not fully sealed or when there are supply issues.
Advantages of High Expansion Nitrogen Foam
High expansion nitrogen foam has the potential to enhance the government’s ability to perform mass depopulation in cases of avian influenza and other notifiable avian diseases. This method is particularly suitable for naturally ventilated poultry buildings and offers several advantages:
1. **Welfare Benefits**: The AWC suggests that nitrogen foam could be as humane, if not more so, than other culling methods that involve live handling.
2. **Rapid Deployment**: The foam can be quickly deployed in various housing types, making it a flexible option in emergency disease control situations.
3. **Effective in Various Conditions**: Unlike carbon dioxide gassing, nitrogen foam does not rely on a fully sealed environment, making it useful in a broader range of scenarios.
Findings from Field Trials
Field trials conducted as part of the study yielded several key conclusions:
1. **Species and Housing Types**: The trials demonstrated that high expansion nitrogen foam is effective across various poultry species, including broilers, broiler breeders, meat turkeys, and meat ducks. Litter-based housing systems were found to be particularly suitable.
2. **Monitoring Challenges**: Once birds are submerged in foam, direct monitoring of their welfare becomes challenging. Therefore, multiple gas monitors and camera systems, including infrared cameras for low-light conditions, are recommended to ensure consistent application and welfare standards.
3. **Foam Application**: Proper placement of foam generators is crucial to creating a broad foam wave that prevents birds from gathering at edges or corners, reducing the risk of smothering. Operators must adjust the foam wave to ensure thorough coverage.
Recommendations
Based on the findings, the report makes several recommendations:
1. **Further Research**: While the anoxic effect of nitrogen foam is expected to affect all poultry species similarly, more research is needed on different housing systems and bird ages to understand any potential behavioral differences.
2. **Monitoring and Adjustment**: Effective monitoring and adjustment of the foam application process are essential. This includes using advanced monitoring equipment and possibly extracting a sample of birds quickly to assess unconsciousness and death.
3. **Regulatory Considerations**: A derogation from the PATOK article 5 requirements, which pertain to monitoring individual birds at the point of killing, should be considered. The confidence generated by scientific studies supports the humane nature of this method.
4. **Foam Generation**: Ensuring proper foam generation from both ends of the shed is vital to prevent smothering and ensure all birds are effectively culled.
Culling Methods and Welfare Impact
When culling is undertaken for disease control, the welfare impacts of the method used should be weighed against the welfare impact of the disease itself. The AWC emphasizes that low or medium expansion foam should not be used for culling poultry, as it causes death by hypoxia, akin to drowning or suffocating, which is not humane according to UK, EU, and World Animal Health guidelines.
Conclusion
High expansion nitrogen foam presents a promising alternative for poultry culling, especially in disease control scenarios. Its welfare advantages, rapid deployment capability, and effectiveness across various housing types make it a valuable tool for the poultry industry. As further research and field trials continue, this method could become a standard practice for humane poultry culling.
For more information, refer to the AWC Opinion on high expansion nitrogen foam for culling poultry available on the UK government website.
