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A global rumen microbes census
The power of global collaboration was shown in the ability to do a global rumen microbes census. New Zealand scientists wondered how typical the rumen microbes found in New Zealand ruminants are globally – a key question if New Zealand hopes to market new solutions it may develop to reduce methane emissions from enteric fermentation.
Through the Global Research Alliance, New Zealand scientists led a global project to compare rumen samples from around the world. They received over 700 contributions from 35 countries, including not only goats, sheep and cattle, but species such as reindeer, giraffes and camels. They found that despite some differences related to feed and species, methanogens are surprisingly similar everywhere. This means that strategies to inhibit dominant methanogens, such as through methane inhibitors being developed by the PGgRc and NZAGRC, are likely to be applicable in grazing based systems globally. This gives further direction and impetus to the domestically funded research and development work.
Breeding animals for reduced methane emission
In the early 2000s, researchers first became interested in the question of whether there is any natural variation between individual animals in the amount of methane they produce. Initially, PGgRc funded a major programme with the dairy industry initiative BoviQuest to measure emissions from 700 individual dairy cows. This trial showed large differences in emissions between animals.
Subsequent work in sheep, funded by SLMACC, established that some animals naturally produce up to 10% less methane than others. Using New Zealand’s strength in breeding sheep, the PGgRc then funded a larger research project that established that methane production is heritable meaning that the difference between low and high emitting animals can be passed through the generations. Having demonstrated feasibility, the work now forms a major ongoing project that is jointly funded by the PGgRc and the NZAGRC to identify genetic markers and rapid measurement techniques that allow these differences to be exploited as part of standard industry breeding programmes. Additional investment through the Government’s GRA fund further allowed New Zealand researchers to connect their work with that conducted in other countries, to share experiences with measurement methods and to establish measurement and reporting protocols to increase the global genetic information and allow intercomparisons on low-emissions traits.
Freeing a methanogen-busting bottleneck
Sometimes the most valuable advances occur at methodological levels. An example of this is a new laboratory technique that allows faster assessment of potential methane inhibiting compounds. Possible compounds are initially identified using a computerised process known as chemogenomics. This allows a rapid scan of many thousands of compounds to identify any that in theory should be able to inhibit the function of methanogens. But the next crucial step is that promising compounds need to be tested in a laboratory, by pipetting the compounds onto plates that contain methanogens, and seeing whether they actually affect the methanogen’s function. The most promising and animal-safe compounds can then be tested in simulated rumen fluids and ultimately in live animals. This initial laboratory testing was a timeconsuming technique, until a team led by local scientists, assisted by international GRA scientists and New Zealand GRA funding, devised a new method. The new technique keeps methanogens, which live in anaerobic conditions, alive in the lab on multi-well plates that allow much higherthroughput testing of many compounds at any time. This has greatly accelerated the ability to test potential methanogen inhibitors, and has identified several promising compounds that are now being taken further in the methane inhibitor programme funded by the PGgRc and NZAGRC.
Maori Farming: Higher production without higher emissions
Maori farms have specific social, economic and cultural purposes, which must be considered when balancing greenhouse gas emissions and broader development goals. The NZAGRC is undertaking a large, three year project with 29 Maori farms nationwide that integrate forestry and livestock. The aim is to assist the Maori pastoral sector to identify ways of improving its efficiency, productivity and profitability while reducing greenhouse gas emissions. Four focus farms serve as sites to identify specific emissions mitigation approaches that would also serve the wider social, economic and cultural goals driving the long-term development of those farms. This project supplements a range of other initiatives that assist Maori agribusiness development, such as the Social Return on Investment evaluation tool implemented by AgResearch and funded by MPI, and MPI’s Pathway to Increased Productivity programme, which assists Maroi landowners to grow and protect their primary sector assets.
Nitrous oxide and soil moisture
On-farm measurements of nitrous oxide that were made to inform New Zealand’s Greenhouse Gas Inventory revealed that waterlogged pastures produce more nitrous oxide. This led to research funded by New Zealand in support of the Global Research Alliance to find out whether nitrous oxide production could be reduced by providing farmers with advice on when animals should be taken off pastures during wet conditions, which would not only reduce emissions but also nitrate leaching and limit pasture damage. This work was carried out using farm data and measurements from New Zealand, Ireland and the United Kingdom. The results from this study highlighted that the benefits and feasibility of managing stock on waterlogged pastures can differ significantly between countries and soil types, emphasising the need for a national and even region-specific approach to mitigate GHG emissions.
Which microbes live in the rumen?
Research funded by the PGgRc laid the groundwork for what is now a comprehensive understanding of rumen microbiology.
A key part of this was sequencing the first genome of a methanogen (the microbes that produce methane in the rumen).
Now, with a boost provided by joint funding from the NZAGRC, the genomes of 11 different methanogen species have been sequenced. The genomic approach has enabled researchers to develop ways of selectively targeting methanogens without affecting the wide variety of other microbes that are essential for the functioning of the rumen. This new knowledge has been fundamental to several subsequent strands of research funded by the PGgRc and NZAGRC, the GRA and SLMACC. These include the identification and testing of methane inhibitors that block the enzyme pathways of methanogens and the development of a vaccine against methanogens.