Interpretive Summary: Repeatability of gaseous measurements across consecutive days in sheep using portable accumulation chambers
By Anne Zinn
Global temperatures are expected to increase over the next thirty years; the implications of climate change will have a large impact on livestock population and production, which will affect food security. Ruminant animals have contributed to 39.8% of global agricultural greenhouse gas emissions, but will play a role in the mitigation of greenhouse gas emissions through the development of sustainable livestock production and the adoption of mitigation measures. In order to reduce methane emissions, it is important to have an understanding of the factors associated with these emissions and have the ability to measure animals in their natural environment. One way to accomplish this is by using portable accumulation chambers, a spot sampling method that enables gaseous emissions from sheep to be measured over a 50 minute period. Limited research exists to ensure that these portable accumulation chamber measurements are indicative of actual emissions, are repeatable over time, and can be quantified accurately with as few measurements as possible.
A study recently published in the Journal of Animal Science investigated the repeatability of consecutive days of gaseous measurements in the portable accumulation chambers, aimed to determine the number of days required to achieve precise gaseous measurements, and developed a prediction equation for gaseous emissions in sheep.
Results indicated that gaseous measurements were moderately repeatable in the portable accumulation chamber over 17 consecutive days and that for portable accumulation chambers to be used on a larger scale, the ranking of animals must remain consistent across time. It was determined that, in order to develop an accurate and robust prediction equation for methane in sheep, a larger dataset is required along with additional variables such as daily matter intake and feed quality. The results from this study will aid the refinement of the protocol for the measurement of gaseous emissions in sheep using the portable accumulation chamber.
The full paper can be found on the Journal of Animal Science webpage.