Scientists on emissions mission

Rebecca TurnerCountryman

Each day, sheep emit on average 20 litres of methane each and cattle 200 litres each, so it is no wonder methane makes up 65 per cent of the agricultural sector’s carbon emissions.

A dedicated team of scientists from around Australia have been undertaking work to research what can be done to reduce the amount of methane each animal emits.

At a carbon farming field day in Moora this week, University of WA animal production systems program leader Phil Vercoe revealed what science had discovered so far about reducing methane emissions from livestock.

He said contrary to popular belief, methane emissions were largely from sheep and cattle burps, with 95 per cent of methane coming from burping and only 5 per cent from flatulence.

Dr Vercoe said there were 18 projects being carried out around Australia into methane emissions at a cost of $46.2 million, co-funded by government and industry.

“By far, the most critical research being carried out in Australia is determining how to quantify methane emissions,” he said.

“Without this understanding of how to accurately record methane emissions, all other projects have nothing to base their methodology on.”

Dr Vercoe said across the 18 projects, there was a huge amount of shared information ranging from breeding to the possibility of manipulating the rumen to reduce methane emissions.

“I don’t think there is a silver bullet and I don’t think we should be aiming for one either,” Dr Vercoe said.

While manipulation of the rumen was a long way off, Dr Vercoe said this did not mean it should remain a mystery.

“The rumen is a dynamic and complicated system and shouldn’t be treated as a ‘black box’,” he said. “Five key organisms make up the microbial soup that is the rumen. These microbes provide energy, protein, methane and ammonia.”

Dr Vercoe said scientists had been interested in the health of the rumen and its influence on production, waste and animal health for some time. He said methane had long been recognised as a loss of energy that could be diverted to faster, more efficient animal growth.

Dr Vercoe said to further understand the impact of diet on rumen health, methane emissions from sheep grazing native grasses and shrubs across southern WA, Victoria, New South Wales and Queensland was recorded.

“The results showed great scope in plant fermentability and methane emissions across the country,” he said.

But for now, Dr Vercoe said for farmers to reduce animal emissions, increasing production efficiency would help. “Producing more lambs per ewe, at a quicker rate to market, will improve your emissions intensity,” he said.

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