Reducing livestock methane emissions

Using forage to reduce methane emissions from livestock

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In this project, scientists are investigating plant foods that reduce methane production in sheep and cattle, and how these plants may be used to benefit Australian livestock production systems.

Utilising anti-microbial properties of plants

All plants contain natural chemicals. Some of these protect the plants against pests or limit the extent to which they are eaten by herbivores (insects or larger animals).

Because some of these plant chemicals have anti-microbial properties, they may be used to reduce the number of methane-producing microbes in the gut of ruminants, thereby reducing methane emissions from livestock.

In collaboration with The University of Western Australia, CSIRO researchers are investigating a wide range of native shrubs and other forages suitable for different farming systems across Australia.

The first step is to screen a large number of plants in laboratory tests that simulate the foregut of sheep or cattle. To identify which plant species have promise, the scientists measure the breakdown of the plant material and the amount of methane produced.

Sheep eating Australian native shrubs.

Some Australian native shrubs can reduce the number of methane-producing microbes in the gut of grazing livestock.

Plants that reduce methane production – known as 'anti-methanogenic plants' – are then tested further to see if their effects are variable or relatively consistent:

  • over time
  • during different stages of plant maturity (e.g. vegetative growth or flowering)
  • across different locations
  • in response to the plants being grazed by livestock.

Plants that continue to show promise in these tests are analysed in yet more detail to better understand the plant chemistry that provides these beneficial effects.

In a final step, anti-methanogenic plants will be fed to animals, under controlled conditions and eventually under field conditions, to confirm if the beneficial effects seen in the laboratory also occur in the real world.

Getting the mixture right

Another part of this research aims to understand the impact of different doses and mixtures of plants on methane production in the gut of livestock. This is very important because the plants will most likely be used as part of a diverse diet offered to grazing livestock.

The scientists are not looking for a single plant that can feed livestock and reduce methane. Rather, they are aiming to identify practical ways to include alternative plants in the diet of grazing animals to achieve multiple benefits, including:

  • whole-farm profitability
  • animal productivity
  • environmental sustainability.

Part of this research involves understanding which plants animals choose to eat when presented with many different plants, and developing management strategies for encouraging livestock to include anti-methanogenic plants in their diet.