1. Antimethanogenic plants
for grazing systems
Durmic, Z. (UWA)
Revell, D., Ramírez-Restrepo, C. (CSIRO)
Moate, P. (DPI Vic)
Ghamkhar, K., Vercoe, P. (UWA)

2. Why do herbivores produce GHG?
Herbivores have evolved to consume large quantities of plants
and can transform poor quality food (grass) into high quality
products (meat and milk).
Cellulose
Meat, milk

3. Methane emissions from livestock
Food Energy
Methane
CO2
Fermentation

4. Methane emissions from livestock
• mechanism of removing hydrogen from the rumen
Substrate
CO2
Fermentation H2
H2
H2
H2 CH4
H2 H2O
H2O
VFA (energy)
CO2 +4H2
CH4 + 2H2O

5. Methane emissions from livestock
Cow Sheep
CH4 per day 200-300L 20-30L
CH4 head/year 100 kg 8 kg

6. Reducing methane from livestock
• dietary, i. e. increasing feed quality (grain)

7. Reducing methane from livestock
• dietary, i. e. increasing feed quality (grain) = expensive,
impact on the environment

8. Reducing methane from livestock
•dietary, i. e. increasing feed quality (grain)
• feed supplements (i.e. antibiotics)

9. Reducing methane from livestock
•dietary, i. e. increasing feed quality (grain)
• feed supplements (i.e. antibiotics) = antibiotic resistance,
becoming ineffective

10. Reducing methane from livestock
•dietary, i. e. increasing feed quality
• feed supplements (i.e. antibiotics)
• vaccine?

11. Reducing methane from livestock
•dietary, i. e. increasing feed quality
• feed supplements (i.e. antibiotics)
• vaccine = ineffective, expensive, side-effects

12. Reducing methane from livestock
– novel approaches
Some novel, safer, long-term and more effective
approaches:
• breeding for low-methane animals
• ‘bioactive’ plants and secondary compounds
• novel and natural feed additives

13. Reducing methane from livestock
– novel approaches
Some novel, safer, long-term and more effective
approaches:
• breeding for low-methane animals
• ‘bioactive’ plants and secondary compounds
• novel and natural feed additives

14. ‘Bioactive’ plants may affect methane output?
•Methane is produced by microbes
•Plant contain secondary compounds (PSC)
• Many ‘bioactvie’ (antimicrobial)
• I.e. tannins - antimethanogenic

15. Why AM plants may be a solution for Australia?
• Part of a normal animal diet
• Our production systems are forage-based
• Great plant diversity in Australia
• Harsh environment = more PSC = more ‘bioactive’

16. Why AM plants may be a solution for Australia?
Plant antimethanogenic potential – EU vs AU
EU ‘Replace’ AU ‘Enrich’
no reduction
5-25% reduction
>25% reduction
500 plants 100 plants
6 active 30 active

17. Why plants may be a solution for Australia?
Other benefits:
• can help transform landscapes
• provide out of season fodder, provide shelter for the animals
• retain water, absorb salt, prevent soil erosion, wind break

18. UWA Research farm
30 Jan 2011

19. UWA Research farm
31 Jan 2011

20. UWA Research farm
31 Jan 2011

21. Why plants may be a solution for Australia?
‘BEFORE’
Monarto (SA) Badgingarra (WA)

22. Why plants may be a solution for Australia?
AFTER
Monarto (SA) Badgingarra (WA)

23. Projects
2005-2008
ENRICH 1 - Multi-purpose
‘healthy’ grazing systems
using perennial shrubs
2008-2010 2009-2011
ENRICH 2 - Building Antimethanogenic
functional and resilient bioactivity of Australian
systems with forage shrubs plants for grazing systems
2010
Variation for in vitro methane production 2009-2012
in pasture legumes with particular focus Using bioactive secondary plant compounds for
on subterranean clover. improving health and function in grazing
ruminants
2011 - 2015
Exploiting the subterranean clover
(Trifolium subterraneum L.) genome to
meet future challenges for Australian
livestock industries - climate change
mitigation and ruminant health.

24. Approach and methodology
Tropical pastures (beef)
Arid (sheep)
Legumes (sheep)
Pastures (beef)
Novel pastures (dairy)
Arid (sheep)

25. Approach and methodology
Collect plant Test in vitro Identify candidates
material

26. Approach and methodology
Expand the screening
Confirm in vivo
Identify PSC
Variability
Management

27. Results

28. Native shrubs(WA and SA, sheep)
90
80
70
60
CH4 (mL/g DM)
50
Oaten chaff
40
30
20
10
0
0 10 20 30 40 50 60 70 80 90 100 110 120
Gas pressure (kPa)
Durmic et al., 2010
• varied methanogenic potential (4 mL/g – 84 mL/g DM)
• plants with beneficial profiles identified

29. Legumes and grasses (WA, sheep)
60
50
Lucerne
40
CH4 (mL/g DM)
30
20
10
0
L.p. B.b. O.s. B.p M.p. T.p. L.r T.s.W. L.c. T.s. M.s. O.c. T.r. T.s.D.
Plant
• varied methanogenic potential (4 mL/g – 51 mL/g DM)

30. Tropical forages (North QLD, beef)
70
60
50 Lucerne
40
CH4 (mL/g DM)
30
20
10
0
Plant sample
• varied methanogenic potential (18 mL/g – 60 mL/g DM)

31. Novel forages (Vic, dairy)
70
60
Lucerne
50
CH4 (mL/g DM)
*
40 *
* * *
30
20
10
0
Forage
• varied methanogenic potential (36 -57 mL/g DM)

32. Novel additives - DHA
• DHA caused small, but significant reduction in methanogenic potential, but only
when mixed with a concentrate diet
80
70
60
*
CH4 (mL/g DM)
50
40
30
20
10
0
Forage DHA/forage Pellet DHA/pellet DHA(o)/pellet
Treatment

33. Moving towards in vivo
Artificial rumen
Confirmation
Dose
Persistence
Animal house Effect on microbes
Which ones?
Static/cidal?
Effect on vital functions
Paddock-scale

34. Results from the artificial rumen
16
14
12
10
CH4 (%)
8
Control
6 EG 25%
4
2
0
7 8 9 10 11 12 13 14 15
Day
• Methane reduced immediately with addition of 25% EG
• Gas production was unaffected
• Effect persisted over 8 days

35. Moving towards in vivo
Artificial rumen
Confirmation
Dose
Persistence
Animal house Effect on microbes
Which ones?
Static/cidal?
Effect on vital functions
Paddock-scale

36. Summary
• Variability exists in methanogenic potential amongst forages
• Differences can be of 10 to 20 times magnitude, however other
factors such as plant nutritive and agronomic value, overall
fermentability and effect on animal should be taken into account
• Plants that have strong antimethanogenic potential, but are not
suitable as fodder, may be part of a mixed diet or developed as an
additive
• Observation so far are based on in vitro (laboratory) testing, but work
is on the way to confirm findings in vivo

37. Partners

38. Antimethanogenic plants
for grazing systems
More info:
zoey.durmic@uwa.edu.au