23-06-2025
Grain-fed cattle emissions 56 per cent lower than previous estimates, research finds
The perception of livestock's contribution to climate change is set to be altered, as the federal government adopts a new way of calculating methane emissions from Australian feedlot cattle.
All cattle producers have been under scrutiny for contributing to about 15 per cent of the world's total greenhouse gas outflow according to CSIRO, but a new Australian-focused emission calculation has disputed the contribution from Australia's grain-fed cattle.
It found grain-fed cattle emissions were 56 per cent lower than previously believed.
For sixth-generation Eugowra farmer and Gundamain Feedlot co-director Caitlin Herbert, this change has significantly shifted the conversation around feedlotters' contribution to climate change.
"It also aligns with our industry's reduction in emissions, and contributes to our goal of net zero."
When a cow burps, or belches, the greenhouse gas methane is introduced into the atmosphere.
A more than 50-year-old calculation that used data from United States dairy cows, known as the Moe and Tyrell equation, had previously created the methodology for grain-fed cattle farmer emission estimates.
Many researchers have questioned its accuracy for Australian cattle.
However, following research conducted by the University of New England (UNE), the Department of Climate Change, Energy, the Environment and Water has adopted a new, Australian-specific equation to calculate methane emissions from grain-fed cattle.
The new methodology takes into account the feed intake of the animals, and adjusts the methane emissions for the amount of roughage, fibre and fat they consume.
The study was funded by Meat and Livestock Australia (MLA) on behalf of the Australian Lot Feeders' Association (ALFA), and the government says it was reviewed by independent experts.
Of Australia's cattle that have gone to slaughter, 40 per cent are grain-fed, according to Meat and Livestock Australia (MLA), and currently make up 1.4625 million tonnes of CO2 equivalents.
Grain-fed cattle emissions are 80–85 per cent lower than grass-fed animals on average, due to the high energy, lower fibre and increased digestibility of grain-based diets.
Owner and co-director of Gundamain Pastoral Co and Gundamain Feedlot Tess Herbert said she had an inkling emissions were being overestimated before the new methodology was released.
"I think the [Australian] grass-fed industry does [believe their emissions are being overestimated] too, so that may be the next step along the supply chain," Mrs Herbert said.
Separate from the study, research fellow Mei Bai at the University of Melbourne's School of Agriculture, Food, and Ecosystem Sciences said it was good news to have a local emission factor formula.
However, Dr Bai said the new coefficients seemed to come from respiration chambers conducted under controlled conditions.
"It doesn't fully replicate commercial feedlots' environment, where animal activities, climate and farm management practices would be different," she said.
"It would be good to validate the revised emission factors with on-farm measurements."
Professor of livestock production at UNE Frances Cowley is the co-author of the equation.
Professor Cowley said the modelling had been under scrutiny for a number of years.
She said MLA and UNE had pulled together recent Australian feedlot data on diets and conditions to conduct new experiments.
"We modelled the data that we had using Australian diets and Australian cattle and Australian conditions and came up with an equation which is a really tight fit and a very strong prediction of methane going to be produced by grain-fed cattle on Australian diets in Australian feedlots," Professor Cowley said.
Being able to track the emissions more accurately means farmers can adjust their cattle's methane-emitting diets.
ALFA president Grant Garey said it was a significant win for the whole industry, solidifying Australia's reputation in all global markets.
"It's a practical win for lot feeders," Mr Garey said.
