Do Australian native shrubs chosen for their in vitro anti- methanogenic potential actually reduce methane in vivo?

1. Do native shrubs chosen for their in
vitro anti-methanogenic potential
actually reduce methane in vivo?
Yakubu Abukari
Supervisors:
Phil Vercoe
Kirrin Lund
Dean Thomas

3. Current sheep production system
Mediterranean climate results in variable feed availability
Annual pastures
Autumn ‘feed gap’  challenge for producers
A potential solution is the inclusion of shrubs in the
grazing system

5. Nutritious plants out-of-season  additional feed source
Using parts of the farm unsuitable for cropping
Drought hardy and responsive to the climate
Shade, shelter and biodiversity in the system
Can improve animal health and productivity
Erosion control
Potential to reduce methane production
Benefits of shrubs in grazing system

6. Hypothesis
Shrubs that demonstrate anti-methanogenic potential
in vitro will reduce methane emissions from sheep
grazing a shrub-based system

7. Why do we need to reduce methane?
Greenhouse gas emissions and climate change is a
global issue
15 % of Australia greenhouse gas emission is from
agriculture
87% of Agriculture GHG emissions comes from methane
produced by ruminant livestock

8. Methane
CO2
Energy loss = 15% FermentationFermentation
Energy (70%)
Food
VFA

9. Enteric methane mitigation approaches
0
5
10
15
20
25
30
35
40
45
Low Medium High
Mitigation%
Supplements
Breeding
Rumen manipulation
Management
Biological control
Effort
Timeline Now
Dietary
∞
Novel grazing

10. Aims
Validate a potential indicator tool for applying in vitro
methane results to in vivo scenarios
Compare in vitro methane production from shrubs to
methane emissions from sheep grazing shrub-based
systems

11. Measuring methane in vitro

12. Measuring methane in vitro cont.

13. Measuring methane in vivo

14. Measuring methane in vivo cont.

15. Pre-treatment
PAC
measurement
Graze treatment plots
for 4 weeks
Post-treatment
PAC
measurement
5 x 16 sheep
in PACs per
day over 3
days
5 x 16 sheep
in PACs per
day over 3
days
Weekly assessments
of:
•Liveweight
•Feed on offer
•Pasture intake
•Shrub intake
Pasture with
grain fed to
maintain live
weight
Pasture with
grain fed to
achieve 140
g LWG
Bioactive
shrubs +
inter-row
Productive
shrubs +
inter-row
3 reps x
16 sheep
3 reps x
16 sheep
3 reps x
16 sheep
3 reps x
16 sheep
3 reps x
16 sheep
Pasture with
grain fed to
achieve 180
g LWG

16. Conclusion
Shrub based grazing system
will fill the autumn ‘feed gap’
reduced supplementary feeding and cost
increased animal productivity
Shrubs with anti- methanogenic potential in grazing
system will reduce methane emission from sheep
In vitro measurement of methane potential of shrubs will
reflect in vivo methane measurement