Livestock emissions

Key points

  • Through the Climate Change Research Program, the Australian Government funded research to develop practical on–farm options to reduce emissions from livestock while maintaining or improving productivity.
  • Researchers trialled a number of methane measurement tools for effectiveness, including open path laser technology.
  • A range of feed alternatives like oil supplements and native plants that can reduce methane emissions were examined.
  • High and low methane emitting livestock sires were tested for their ability to pass these traits onto offspring.
  • Five national demonstration sites across the country exhibited outcomes from the research.

Direct livestock emissions account for around 10 per cent of Australia’s greenhouse gas emissions.

Methane and nitrous oxide are significant greenhouse gases as they have much greater global warming potential than carbon dioxide. Reducing methane and nitrous oxide emissions from livestock will help reduce Australia’s overall greenhouse gas emissions and mitigate future climate change.

The economic and environmental benefits of adopting practices that reduce emissions may include: improving the conversion of feed to energy, reducing nitrogen losses from intensive production systems and the potential to create offsets under the Carbon Farming Initiative.

Measuring methane emissions from livestock

The Reducing Emissions from Livestock Research Program improved Australia’s ability to accurately measure methane emissions from livestock. Accurate measurements allowed the effectiveness of different methane reduction methods to be tested. The program also compared the accuracy of different measurement techniques. Closed systems, the established method used for measuring methane emissions, were used at a number of research sites around the country. Other techniques to measure emissions from animals in the paddock were also used. These paddock–based techniques include:

Open path technology

Laser and infra–red open path techniques were tested for their effectiveness in measuring greenhouse gas emissions from grazing livestock. These techniques sent beams of light across paddocks containing grazing animals and then analysed the reflected light for greenhouse gas concentrations. Early results show that this technology can accurately measure methane emissions from livestock in small paddocks.

Tracer Gas Technique

This technique also allowed emissions to be measured from animals grazing in the paddock. The technique used a tracer gas that was released at a known rate from a canister in the animal’s rumen. The animal then belched methane as normal, along with the tracer gas. The two gases were sampled in a collar worn by the animal. The ratio of methane and tracer gas was analysed to determine the rate at which methane was produced by the animal.

Managing and measuring emissions from manure

Gas recorders were used to assess the amount of methane and ammonia released from manure stockpiles. Ammonia can be a precursor for nitrous oxide emissions and comes from animal urine and manure. Results showed that ammonia emissions from manure stockpiles are carried by wind to adjoining land where they may become a source of nitrous oxide emissions.

More effective management of manure stockpiles may reduce methane and nitrous oxide emissions. The Reducing Emissions from Livestock Research Program examined the effectiveness of two manure management practices.

Manure stockpile aeration and composting

Both aeration and composting may reduce the amount of methane that is produced from manure stockpiles. Researchers refined appropriate methods and analysed their methane reduction potential.

Urease inhibitors

Researchers examined ways to reduce nitrous oxide emissions from manure by using urease inhibitors on feedlot manure stockpiles. Urease inhibitors are chemical additives that stop urea (found in animal urine and manure) converting to nitrous oxide. Results showed that applying urease inhibitors decreases the rate at which nitrous oxide is emitted from manure.

Adapting rumen function

A diverse group of microbes in an animal’s rumen create energy through food digestion, releasing methane as a by–product. The Reducing Emissions from Livestock Research Program looked at a number of ways to reduce methane production in the rumen by changing the way it operates. Methods trialled included: animal breeding, biological controls, dietary supplements and feeding new forage plants.

Animal breeding

Researchers investigated whether livestock could be bred as low methane emitters without compromising production. High and low methane emitting cattle and sheep sires were identified through the Reducing Emissions from Livestock Research Program. The offspring of these sires were assessed for their methane production. Rumen samples from these animals were also analysed to identify the best indicators for measuring methane production in the rumen.

Biological controls

Three biological control methods were examined for their ability to reduce methane production from livestock. The first used viruses to attack the microbes which produce methane; the second used specialised proteins to target methane producing microbes; and the third used other microbes (methanotrophs) to break down the methane produced in the rumen into other substances.

Dietary supplements and feed alternatives

A range of dietary supplements and feed alternatives were trialled to assess whether they can reduce methane emissions from livestock. Supplements included oils, fats, tannins, probiotics, nitrates, enzymes, marine algae and Australian native vegetation. Laboratory experiments showed that some dietary oil and fat supplements can reduce methane emissions. Analysis using on–farm research indicated that certain oil and fat supplements can reduce emissions by around 10 per cent in Victorian dairy systems.

Research showed that the methane inhibitor bromochloromethane reduces methane levels by up to 91 per cent in goats. While this technology is not used under commercial conditions it does provide evidence on how the rumen adapts to conditions where methane production is reduced. This information is important when developing future techniques that minimise methane production without affecting animal productivity.

Feeding new forage plants

Several alternative plant forages such as broccoli leaves and some Australian natives (tar bush, the golden wreath wattle and a number of salt bush species) have been shown to reduce methane emissions in laboratory experiments.

Mapping rumen microbiology

In order to understand the effect of dietary changes on methane production, researchers examined the complex microbiology of the rumen. This project successfully developed a sound method to examine the effects of dietary interventions on the rumen microbe population that creates methane.

Communicating research outcomes

To aid in the communication and extension of the Reducing Emissions from Livestock Research Program’s research findings, five national demonstration sites were established. These were located at:

  • University of New England, Armidale, NSW
  • CSIRO Lansdown Research Station near Townsville, Qld
  • University of Western Australia, Pingelly, WA
  • Demo–dairy near Terang, Vic
  • Department of Primary Industries Victoria, Hamilton, Vic.

Producers and industry stakeholders were engaged through a number of forums and training workshops held on each demonstration site.

Partnerships

Research presented in this fact sheet is a result of partnerships between:

  • Australian Wool Innovation
  • CSIRO
  • Dairy Australia
  • Department of Primary Industries Victoria
  • Meat and Livestock Australia
  • Sheep CRC
  • South Australia Research and Development Institute
  • University of Melbourne
  • University of New England
  • University of Queensland
  • University of Western Australia
  • University of Wollongong

About the Climate Change Research Program

The Climate Change Research Program was part of Australia’s Farming Future, an Australian Government climate change initiative for primary industries. The program funded research projects and on–farm demonstrations to help prepare Australia’s primary industries for climate change. Research focused on reducing greenhouse gas emissions, improving soil management and climate change adaptation. The program provided practical management solutions to farmers and industries.The Department of Agriculture, Fisheries and Forestry managed the Climate Change Research Program.

Acknowledgement

Information contained in this fact sheet was obtained from a research progress report provided by Meat and Livestock Australia, including input from the research partners listed.