Summary
Agriculture produces 16% of national greenhouse gas emissions in Australia mainly as methane and nitrous oxide. Prior research has shown that dietary supplements can reduce methane emissions from cattle by 20%. This project evaluated a range of dietary oil supplements, tannin, micro algae oils and grape marc for effects on methane emissions, milk yield and milk composition in dairy cows. The findings of the project have also improved the methods for measuring methane from individual animals (SF6 tracer) and groups of animals in the field (Open Path Tracer). Oil supplements and grape marc have shown potential to reduce methane without negative impacts on productivity, allowing the development of an offset method that will allow farmers to claim carbon offset credits under the Carbon Farming Initiative. Further research is now required to investigate combinations of forages and supplements for reducing methane and improving productivity in sheep and cattle.
