Interpretive Summary: validation of the GreenFeed system for measuring enteric gas emissions from cattle
By Anne Zinn
A study recently published in the Journal of Animal Science evaluated the use of the commercially available GreenFeed system for measuring enteric gas emissions from cattle. Reducing greenhouse gas emissions while maintaining animal productivity has been a popular topic in the past two decades, which has led to numerous recommendations for mitigation strategies. While these are crucial findings, there are knowledge gaps on how to best mitigate greenhouse gas emissions because of the uncertainties associated with methods used to derive emission rates. For this reason, a team at the Lethbrdige Research and Development Centre in Canada compared emission rates of methane and carbon dioxide measured by a GreenFeed system with those from a mass flow controller that released known quantities of gas over time and a respiration chamber. The comparison was conducted in an open environment, simulating a pasture, and inside a respiration chamber, representing a barn.
Results of the present study indicate that the GreenFeed system accurately estimated enteric methane and carbon dioxide emission rates of cattle over a short measurement period. The difference between the GreenFeed and mass flow controller was 1% for methane and 3% for carbon dioxide, and the difference between the GreenFeed and respiration chamber was 1% for both methane and carbon dioxide. Upon further examination, the small difference in carbon dioxide emission rates between systems could be attributed to systematic offset error, indicating a correction factor could be applied.
To conclude, it was determined that the GreenFeed system has the potential to accurately measure emission rates from cattle when used in an open environment or well-ventilated barn, but additional factors would need to be considered in determining the 24 hour emission rate of an animal.
The full paper can be found on the Journal of Animal Science webpage.