The research, undertaken as part of the Reducing Emissions from Livestock Research Program, showed that feeding cattle brewers’ grain can reduce methane emissions by 15-20%.
It also revealed that other waste products that are high in oil – including whole cottonseed meal, cold–pressed canola meal and hominy meal – have a similar effect
Associate professor Richard Eckard, director of the Primary Industries Climate Challenges Centre at the University of Melbourne, said: “For every 1% of oil added to a ruminant’s diet, it translates to a 3.5% reduction in methane emissions.”
Researchers found that the oil had the biggest effect if added when pasture was limited and of poor nutritional quality.
“In spring, our rye grass gets up to around 5% oil anyway and you cannot go above 7%, so you don’t have as much margin,” said Eckard.
Drenching cows with tannin was also found to reduce methane emissions by up to 29%, but the scientists said that it was not a suitable feed additive.
“But tannin is very bitter and we had trouble getting cows to eat it voluntarily,” Eckard said.
The Reducing Emissions from Livestock Research Program is a joint initiative by Meat & Livestock Australia and the Federal Government’s Department of Agriculture, Fisheries and Forestry. It is part of the Australian government’s Climate Change Research Program, which aims to make research outcomes useful to industry.
Julia Gaglia, from the Department of Agriculture, Fisheries and Forestry, said: “The Australian Government is working with researchers, industry and farmers to ensure that science addresses the effects of a changing climate in a way that will help land managers improve their management practices and remain profitable and sustainable.”