Australian beer drinkers are helping cattle producers reduce methane produced by cows and they don’t even know it.
The by-product of the beer making process, brewer’s grain, is just one waste product which scientists have shown can reduce methane emissions in cattle by 15 to 20 per cent.
Julie Gaglia from the Department of Agriculture, Fisheries and Forestry said the Reducing Emissions from Livestock Research Program was part of the Australian Government’s Climate Change Research Program, which is aimed at making research outcomes useful and applicable to industry.
“The Australian Government is working with researchers, industry and farmers to ensure the 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,” Ms Gaglia said.
Associate Professor Richard Eckard, Director, Primary Industries Climate Challenges Centre at the University of Melbourne said the project aims to develop practical feeding strategies that dairy farmers can implement to curb methane emissions and maintain profitability.
“Methane is 25 times more potent than carbon dioxide. And each grazing dairy cow can burp up to 600 grams of the gas per day,” Associate Professor Eckard said.
The project has investigated several waste products that are high in oil including whole cottonseed meal, cold-pressed canola meal, brewers’ grains and hominy meal as feed additives for dairy herds.
“For every one per cent of oil added to a ruminant's diet it translates to a three-and-a-half per cent reduction in methane emissions,” Associate Professor Eckard said.
“In the case of whole cottonseed, it not only significantly reduced methane emissions but also increased milk production by 16 per cent, milk fat by 19 per cent and milk protein by 12 per cent.”
The results show that the most valuable time for the oil to be added is when pasture is limited in quantity and has a low nutritional value.
“In spring, our ryegrass gets up to around five per cent oil anyway and you can't go above seven per cent, so you don't have as much margin,” Associate Professor Eckard said.
“But in summer, when pasture oil content is around two per cent, adding five per cent oil could reduce emissions by 15–20 per cent. It would also increase milk production due to the slow-release energy provided by oil.”
The study also found that drenching cows with tannin can also reduce methane emissions by up to 29 per cent.
“But tannin is very bitter and we had trouble getting cows to eat it voluntarily,” Associate Professor Eckard said.
The project team has also developed a reliable way to measure methane on a larger scale.
“In order to ensure that the various supplements we studied delivered actual methane reductions in a practical sense, we used the open-path FTIR method,” Associate Professor Eckard said.
“This involves measuring methane emissions by shooting beams of light up and down wind of the animals so that measurements can still be taken while the animals are grazing in the herd or flock.”
The project is part of the Reducing Emissions from Livestock Research program — a joint initiative of Meat & Livestock Australia and the Federal Government’s Department of Agriculture, Fisheries and Forestry and is supported by the Victorian DPI, University of Melbourne and Dairy Australia.