Climate change is a growing international concern and it is well established that the release of greenhouse gases (GHG) is a contributing factor. The European Union has committed itself to reduce its GHG emissions by 20% by the year 2020 relative to 1990 levels. The global livestock sector, particularly ruminants, contributes approximately 18% of total anthropogenic GHG emissions. In the EU, the livestock sector accounts for about 13% of total GHG emissions. Of the various GHG produced by ruminants, enteric methane (CH4) is the most important contributor, with a global warming potential 25 times that of carbon dioxide (CO2).
Technical solutions to reduce enteric methane emissions have been, and continue to be, extensively researched. Animal breeding that exploits natural animal variation in methane emissions is an additional mitigation strategy that is cost-effective, permanent, and cumulative. Successful animal breeding strategies require measurements on a large population of animals. With the recent successful incorporation of genomic information into breeding schemes the reliance on very large populations of phenotyped animals is somewhat relaxed. However, a reference population of several thousand animals is still required to estimate the contribution of each genomic region to expression of the phenotype under investigation. Therefore, a dataset of several thousand animals with similarly defined phenotype for methane output would be sufficient for accurate genetic evaluation of the trait.
In the Netherlands, we measure enteric methane emissions of individual dairy cows with a non-invasive infrared gas analyser. Currently, 500 individual cows are recorded, but plans are to increase this database to several thousand animals in the near future. An international collaborations through METHAGNE (COST Action FA1302) is set up as well, aiming to discuss and agree on 1) protocols to harmonise large-scale methane measurements using different techniques; 2) easy to record and inexpensive proxies for methane emissions to be used for genetic evaluations; and 3) approaches for incorporating methane emissions into national breeding strategies.
Together with QLIP (Zutphen, the Netherlands) a pilot has started to link the enteric methane emissions to mid infrared (MIR) spectral data in the milk of these cows. Various fatty acids in milk may be used as markers of microbial activity, and some have strong relationships with molar proportions of individual volatile fatty acids in the rumen, which in turn are related to methane production. Therefore, the MIR spectral data can be a good proxy for the methane emission of that individual cow. Mid-infrared spectra of milk samples are generated routinely by national and commercial laboratories, which provides a large scale availability of the data.
For more information, please contact Yvette.deHaas@wur.nl