Section 20: Methane measuring methods
NOTE: This version of Section 20 has been approved by the working group's Chair. Please be aware that further revisions may occur before final review and approval by the Board and ICAR members per the Approval of Page Process.
Several factors influence the choice of measurement method such as cost, level of accuracy, precision, scope of application, and scale, which vary across disciplines (Cassandro et al., 2013[1]; Hammond et al., 2016A[2]; Garnsworthy et al., 2019[3]). For instance, genetic selection programs require CH4 measurements on thousands of related individuals under the environmental conditions in which the animals are expected to perform (Falconer and Mackay, 1996[4]). This can be challenging because dairy cattle perform in a wide range of conditions (e.g. grazing vs indoor housing). There are a number of different measurement methods currently being employed, each with advantages and disadvantages in terms of the factors listed above. The currently accepted and widely used measurement methods are listed and described below. The main features of methods for measuring CH4 output by individual animals are summarised in Table 4. Values for each feature are based on experience of experts in METHAGENE WG2 who have used the methods. All values are relative, and somewhat subjective, because absolute values will depend on installation and implementation of each method at different research centres. It should be noted that the measuring methods can be divided in two major sections: methods that measure the concentration and flux of CH4 (e.g. the respiration chamber), and methods that measure the flux of CH4 through the device (e.g. GreenFeed). This affects the useability of the methods for answering research questions – please see also the recommendations at the end of these guidelines.
- Respiration chamber
- Portable Accumulation Chambers
- SF6
- Breath sampling during milk and feeding
- Sniffer SOP
- Greenfeed
- Greenfeed SOP
- Laser Methane Detector
| Table 1. Table one caption (in first row of the table). | ||||||
|---|---|---|---|---|---|---|
| Method | Purchase cost | Running costs | Labour | Repeatability | Behaviour alteration | Throughput |
| Respiration chamber | High | High | High | High | High | Low |
| SF6 technique | Medium | High | High | Medium | Medium | Medium |
| Breath sampling during milking and feeding | Low | Low | Low | Medium | None | High |
| GreenFeed | Medium | Medium | Medium | Medium | Medium | Medium |
| Laser methane detector | Low | Low | High | Low | Low-Medium | Medium |
Table 4. Summary of the main features of methods for measuring CH4 output by individual animals.
- ↑ Cassandro, M. 2013. Comparing local and cosmopolitan cattle breeds on added values for milk and cheese production and their predicted methane emissions. Animal Genetic Resources/Ressources génétiques animales/Recursos genéticos animales, available on CJO2013. doi:10.1017/S2078 63361200077X
- ↑ Hammond, K.J., Crompton, L.A., Bannink, A., Dijkstra, J., Yáñez-Ruiz, D.R., O’Kiely, P., Kebreab, E., Eugenè, M.A., Yu, Z., Shingfield, K.J., Schwarm, A., Hristov, A.N., and Reynolds, C.K. 2016A. Review of current in vivo measurement techniques for quantifying enteric methane emission from ruminants. Anim. Feed Sci. Technol. 219:13–30. doi:10.1016/j.anifeedsci.2016.05.018.
- ↑ Garnsworthy, P.C. Difford, G.F. Bell, M.J. Bayat, A.R. Huhtanen, P. Kuhla, B. Lassen, J. Peiren, N. Pszczola, M; Sorg, D. Visker, M.H., and Yan, T. 2019 Comparison of Methods to Measure Methane for Use in Genetic Evaluation of Dairy Cattle. Animals 9:837, 12p.
- ↑ Falconer, D., and Macka,y T. 1996. Introduction to quantitative genetics (4th edn). ISBN-13: 978-0582243026; ISBN-10: 0582243025
