This document discusses potential methods for reducing methane emissions from livestock, which account for 14.5% of global greenhouse gas emissions. It outlines several dietary strategies that have shown promise for reducing enteric methane in livestock, including tannin-rich forages, oils/lipids, and seaweed. It also discusses rumen modifiers like 3-nitrooxypropanol, early life programming to modify rumen microbes, and vaccination strategies. Additional methods discussed include improving animal and herd management, animal breeding to select low-methane emitting animals, and reducing unproductive animals. Achieving significant on-farm methane abatement will require intensive research on low-cost and sustainable long-term solutions suited for both intensive and extensive livestock

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Primary Industries Climate Challenges Centre
Success example:
The potential for livestock methane mitigation
Richard Eckard
International Tropical Agriculture Conference Brisbane, Australia,
11-13 November 2019

2. • Reducing its emissions of GHG methane and nitrous oxide
• 6% of global GHG as CH4
• 14.5% of global GHG
– Increasing challenge on social licence
• Increasing vegetarianism in developed countries
• BUT Increasing demand for animal-based protein in emerging economies
Livestock production under pressure
after Thornton (2010) Gerber et al. (2013); FAO 2009; 2017

3. COP21 Paris Agreement
• Net zero emissions from 2050
– Any remainder GHG emissions post-2050 need to be offset
– Business and governments are aiming to comply

4. • Mato Grosso do Sul, Brazil
– Carbon neutral initiative (incl livestock)
– Carbon neutral Brazilian beef (Embrapa)
• Meat and Livestock Australia
– “Australian beef can be carbon neutral by 2030”
• Given the right industry, R&D and policy settings
• Carbon neutral red-meat in Australia
– Arcadian Organic & Natural’s Meat Co’s
– NAPCO Five Founders beef brand
– Flinders + Co Meats
Carbon (climate) Neutral Livestock

5. Pathways to reduce enteric methane
Animal
Manipulation
Rumen
Manipulation
Diet
Manipulation
Plant
Breeding
Dietary
Supplements
Dietary Oils
Probiotics
Management
Systems
Forage
quality
Alternative
livestock systems
Animal
Breeding
Biological
Control
Vaccination
Bacteriophages
bacteriocins
Chemical
Defaunation
Reductive
Acetogenesis
Enzymes
Plant Secondary
Compounds
Tannin &
Saponin
Technologies to Reduce
Enteric Methane Emissions
Dicarboxylic
acids
Unproductive
Animals
Residual Feed
Intake
Efficiency
Eckard et al. 2010

6. • Tannin e.g. Legume forages
– Black wattle
• 10-22% less CH4
– Grainger et al. (2009)
– Leucaena
• 11% to 21% less CH4
– Kennedy and Charmley (2012)
– Lotus
• 5 to 15 CH4 /kg DMI
– Browne et al. (2014)
– Variable responses at low concentrations
– Decline in digestibility and DMI ?
Solutions to enteric methane
Diet manipulation
Harrison et al. (2015)

7. • Oils/Lipids
• e.g. cotton seed, cold pressed canola seed
– 1% added fat = 3.5% less CH4
– Moate et al. (2011)
– High lipid grass (% oil content)
– Jonker et al. (2018)
• Lipid and tannin
– Grape marc (20%)
– Moate et al. (2014)
– Cottonseed oil (14%) + Tannin (11%) = 20%
– Williams et al. (2019)
Solutions to enteric methane
Diet manipulation
Moate et al. (2011)

8. Solutions to enteric methane
Diet manipulation
• Asparagopsis taxiformis
– >90% less in vitro CH4
– Machado et al. (2014)
– >80% less in vivo CH4 (sheep)
– Li et al. (2018)
• Contains
– Bromoform halogenated compounds
– Van Nevel and Demeyer (1996)
Tomkins et al. (2015); Li et al. (2018)

9. Solutions to enteric methane
Rumen modification
• 3-nitrooxypropanol (3-NOP)
• Inhibitor of methaogenesis
– Duval and Kindermann (2012)
– In vitro (85-96%)
– Martínez-Fernández et al. (2014)
– In vivo (30-42%)
• TMR Dairy
– Hristov et al. (2015)
• Feedlot
– Vyas et al. (2018)
– Grazing systems
• Controlled release technology needed?
Hristov et al. (2015)

10. Solutions to enteric methane
Rumen manipulation
• Early life programming
– Maternal influence on microbial community structure post-weaning
– Yáñez-Ruiz et al. (2015)
– Nutritional intervention in early life =>
• Modified structure of the archaeal community
– Abecia et al. (2014)
– Holds potential for
• Low-cost, intergenerational, sustainable solution
– No conclusive results yet
• Potential mitigation unknown
Jiao et al. (2015); Yáñez-Ruiz et al. (2015)

11. Solutions to enteric methane
Rumen manipulation
• Vaccination
– Methanogen surface proteins have been shown to be immunogenic in ruminants
– Saliva antibodies shown in sufficient quantities
– Ultimate CH4 impacts still unclear
– Important potential longer-term
Wedlock et al. (2013)

12. Solutions to enteric methane
Animal manipulation
• Animal and herd management
• Reducing unproductive animals
– Health and management
– Eckard et al. (2010); Reisinger et al. (2017)
– Extending lactation
• Changing the effective replacement rate
– Browne et al. (2014)

13. Solutions to enteric methane
Animal manipulation
• Animal breeding
– Moderate heritability for CH4 /kg DMI
• (h=0.2 cattle)
– Pickering et al. (2015)
• Could be related to passage rate
» Pinares-Patiño et al. (2013); Cabezas-Garcia et al. (2017)
– Potential longer-term
• Dairy: 5 to 10% decrease
– (J. Lassen, Viking Genetics)
• Sheep: 10 to 20% decrease
– (S. Rowe, AgResearch, NZ)

14. • Options for significant CH4 abatement on farm
– High potential - Intensive systems
– Limited potential – extensive or subsistence systems
• Need more research on
– Low-cost, intergenerational, sustainable solution
– Suited to small scale and subsistence livestock systems
• A global priority
– Cannot be addressed with traditional 3-year funding paradigms
– A global collaboration is required
In Summary