Methane Emissions from Ruminants in Australia: Mitigation Potential and Applicability of Mitigation Strategies
John L Black Consulting, Warrimoo, NSW 2774, Australia
Livestock Productivity Partnership, University of New England, Armidale, NSW 2351, Australia
Ilona Box Consulting, Warrimoo, NSW 2774, Australia
Author to whom correspondence should be addressed.
Academic Editor: Mohammad Ramin
Received: 12 March 2021
Revised: 25 March 2021
Accepted: 26 March 2021
Published: 29 March 2021
Methane is a potent greenhouse gas. It is 80-times more effective at heating the earth than carbon dioxide over the first 20 years following release into the atmosphere. Ruminant animals have diverse microbial populations in their stomachs that employ anaerobic fermentation to digest feed. Methane is belched into the atmosphere as a by-product of the digestive process. This gut, or enteric methane, primarily from cattle, but also sheep and goats, contributes 30% of the methane released into the earth’s atmosphere each day, and is more than any other single methane source. A major reduction in methane emissions from ruminants is crucial to preserve ecosystems on the planet. Various strategies to reduce enteric methane emissions in farm operations are reviewed to quantify their mitigation potential, determine their impact on animal productivity and likelihood of adoption. Two feed supplements, a commercial product, 3-NOP (Bovaer®), and the seaweed, Asparagopsis, can reduce methane emissions by 40+% and 90%, respectively, with associated increases in animal productivity and no adverse effects on animal health or product quality. The rumen microbial population can also be changed to provide long-term intergenerational reduction in methane emissions, if treated herds remain isolated from non-treated animals.