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Stand clear for the methane busters

Adding red seaweed to livestock feed may hold the key to tackling methane emissions, writes Brett De Hayr.

Research | Partners

Methane is estimated to contribute about 14.5 per cent of anthropogenic, or human-generated, greenhouse gas emissions. And one of its main sources happens to be one of our key industries: livestock. It’s a problem for the atmosphere and, potentially, for an industry already in the crosshairs of governments around the world which are looking for ways to cut greenhouse gas emissions to reach global targets.

Australian meat, wool and dairy industries are trialling new technologies and practices to reduce their methane emissions in line with the principles of the Global Methane Pledge, signed by more than 120 countries. Closer to home, dairy giant Fonterra has been working with Tasmanian dairy farmer Richard Gardner and local company Sea Forest in trials of red seaweed, also known as asparagopsis, as livestock feed.

Methane emitted from livestock and other sources is many times more potent - in terms of global warming – than carbon dioxide. Although CO2 has a longer-lasting effect, methane, a short-lived gas, accelerates the pace of atmospheric warming in the short term. If we want to limit the global temperature immediately, we need to tackle methane.

The University has launched a range of research projects to help livestock industries manage their greenhouse gas emissions. Experiments with asparagopsis are a big part of this picture.

The research is being done at our Institute for Marine and Antarctic Studies, based in Hobart, and the Tasmanian Institute of Agriculture, which will be headquartered in Launceston from 2024. We’re acutely aware that a fix for this problem will bring enormous benefits to the island, and far beyond.

Asparagopsis, which is endemic to Australia and New Zealand, has been shown to dramatically reduce methane produced in the intestines of livestock.

At the University we’re exploring ways to grow red seaweed in the cool waters of southern Tasmania and feed it to livestock at three large commercial Tasmanian farms – in effect, a “surf and turf” approach.

A key challenge is to find the right delivery mechanism to administer the correct dose of seaweed to grazing livestock.

This is critical to achieve the balance between methane abatement and animal productivity. Studies have shown that relatively small additions of asparagopsis in cattle feed can reduce their methane emissions. Based on results so far, we think these emissions can be cut by about 50 per cent, well in excess of the international target of 30 per cent.

It’s been claimed that asparagopsis can reduce methane emissions in livestock by a dramatic 98 per cent, and that’s certainly true in controlled experiments. However, too much asparagopsis in an animal’s diet can suppress its appetite and limit its production of meat, wool and milk, which is not good for the animal - or the farmer. We’re looking at ways to combine asparagopsis with other substances that may amplify its methane-busting benefits while avoiding some of these drawbacks.

If a way can be found to apply these findings commercially to livestock, we can knock its greenhouse gas emissions down dramatically.

Brett De Hayr is a researcher at the Tasmanian Institute of Agriculture.

Main image: Asparagopsis, Coles Bay

This story features in the 2023 edition of It's in our nature - a collection of stories that celebrate and highlight the unique work being undertaken by our institution, and the people within it, to deliver a more fair, equitable and sustainable society.

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