Methane Mitigation In Ruminants Through Nutritional Interventions

1. Speaker:
Dr Brishketu Kumar
Assistant Professor
Dept. of Animal Science,
College of Agriculture,
NAU, Bharuch

2.  Global warming and climate change is one of the most
critical global challenges of our time
 Globally, ruminants produce 80 MMT of methane annually
(NRC, 2002)
 India has largest livestock population & emit about 10.8
MMT of CH4 annually from enteric fermentation
(Singh and Sikka, 2007)
 Livestock sector is responsible for 35–40% of
anthropogenic methane emissions mainly from enteric
fermentation in ruminants and animal wastes
(Steinfeld et al., 2006)

3.  In ruminants, 87% CH4 is produced in rumen & remaining
13% from hindgut fermentation
(Moss et al., 2000)
 Energy loss ranges from 2 to 12% of GE intake in cattle
(Johnson and Johnson, 1995)
 Ability of methane to retain heat is 21 times more than
carbon dioxide
(Frank 2004 )
 This necessitates finding newer strategies to reduce
methane production and enhance nutrient utilization

4. What is enteric methane?
Methanogenesis?
• Enteric fermentation is a natural part
of the digestive process of
ruminants where microbes
decompose and ferment feed
present in the digestive tract to
produce energy and protein along
with methane.
 Methanogenesis helps to maintain
low partial pressure of H2 in rumen –
thus providing favorable
environment for degradation of cell
wall carbohydrates.
(Liu & Whitman, 2008)

5. Pathways for Methanogenesis

6. Site of methane production
and excretion in ruminants

7. What are methanogens?
• Use hydrogen to reduce
CO2 to methane (CH4 )
• Usually coccoid or rod-
shaped
• Obligate anaerobes
• Over 50 species have been
identified String of methanogens

8. • Seven species of methanogens – cultured from rumen.
(Janssen & Kris,
2008)
Methanobacterium formicicum
M. bryantii
Methanobrevibacter ruminantium 30-99%
M. millerae
M. olleyae
Methanomicrobium mobile 0-54%
Methanoculleus olentangyi
Methanosarcina Spp. 2-3%

9. What is the need of Methane Mitigation?
Firstly, less methane means a lower
concentration of greenhouse gases (GHGs) in
the atmosphere.
Secondly, less methane means increased
efficiency of livestock production and
increased income for farmers.

10. Schematic Presentation of the Potential Targets
to Reduce CH4 Emissions from Ruminants

11.  Acetate and butyrate promotes methane production,
whereas propionate formation conserves H2 there by
reducing CH4
(Wolin & Miller, 1988)
C6H12O6 + 2H2O → 2C2H4O2 (acetate) + 2CO2 + 8H
C6H12O6 + 4 H → 2C3H6 O2 (propionate) + 2H2O
C6H12O6 → C4H8 O2 (butyrate) + 2CO2 + 4H
CO2 + 8H → CH4 + 2H2O

12. Strategies to Mitigate Methane Production
Management strategies
Nutritional strategies
Carbohydrates
Frequency of feeding
Forage species and its
maturity
Complete feed
block/TMR
Processing of forage
Silage feeding
Manipulation of
rumen fermentation
1. Ionophores
2. Defaunation
3. Addition of fat & oils
4. Probiotics
5. Propionate enhancers
6. Plant 20 compounds
7. Immunization
8. Use of chemicals
9. Reductive
acetogenesis
10. Prebiotics
11. Electron acceptors
12. Hexose partitioning
13. Rumen methane
oxidation
14. Bacteriocins
15. Bacteriphages
Number and
productivity of
animals
Genetic
selection of
animals

13. Feeds and Feeding Practices
Improved
Forage Quality
and
Management
Mechanical
Feed
Processing
Feeding
Concentrates
Nutrient
Balancing
Precision
Feeding
Mode of
Action
Enhances
forage
digestibility
Enhances
forage
digestibility
Propionate
Acetate
Availability
of essential
nutrients
Meet animal
requirements
Productivity
Impact
Methane
Reduction
Applicability All systems All systems All systems Mainly
confined
systems
Mainly
confined
systems

14. Frequency of Feeding
 Low frequency feeding – increase propionate, reduced
acetic acid production - lowered CH4 production.
(Shabi et.al., 1999)
 Low frequency feeding – increase diurnal fluctuations in
ruminal pH - inhibitory to methanogens.

15. Forage Species and its Stage of Growth
 CH4 production – tends to increase with maturity of forage
fed and CH4 emission from rumen fermentation of legume
forages < grasses.
(Moss et.al., 2000)
 Lower CH4 with legumes – lower proportion of structural
CHO in legumes & faster rate of passage – shift the rumen
fermentation pattern towards high propionate production.
(Johnson and Johnson,
1995)

16. Processing of Forage
 Grinding/pelleting – decrease CH4 losses – 20-40%.
 Grinding/pelleting – lower fibre digestibility, decrease
ruminally available OM and faster rate of passage.
Silage Feeding
 CH4 production - lower when forages – ensiled
(Sundstol, 1981)
 Ruminal fermentation of silage – higher butyrate, lower
acetate proportion.

17. Complete Feed Block/Total Mixed Ration
 Feeding complete feed block (70% R: 30% C) – better
productivity and lowered CH4 production – 10%.
 Similar results observed with TMR
 Best suited under our conditions – helps in better
utilization of unconventional feed – lowering methane
production.

18. Methane Production Decreases with
Increasing concentrate proportions of diets
Replacing fibrous concentrates with starchy concentrates
Increasing the digestibility of forage
With legumes compared to grass forages
With silages compared to hay
Benchaar et al.
(2001)

19. Feed Supplements and Feed Additives
Ionophores Organic
Acids
Plant
Extracts
Dietary
Lipids
Halogenated
Compounds
Probiotics
Examples Monensin,
Lasalocid
Nitrate,
Malate,
Fumarate
C. Tannins,
Saponins,
Essential
oils
Vegetable
oils, Fish oils,
Sunflower oil
etc.
Bromochlorom
ethane,
Chloroform
Yeast,
Lactobacillu
s strains.
Mode of
Action
Propionate,
H2 sink
H2 sink Protozoa
& Archaea,
H2 sink
Protozoa Archaea
inhibition Propionate,
H2 sink, pH
Producti
vity
Impact
DMI DMI DMI DMI
Long
Term
Effect
Microbial
adaptation
Microbial
adaptation
Microbial
adaptation
Not clear Microbial
adaptation
Varying
results
Applicabi
lity
Confined animals

20. Ionophores
 Ionophores – added to ruminant diets - improve
efficiency of feed utilization – decrease CH4 production.
(Moss et.al., 2000)
 CH4 production - decreased up to 76% in vitro & 18% in
vivo.
(VanNevel and Demeyer 1996)
 Monensin – reduction of gram +ve bacteria &
proliferation of gram –ve bacteria – concurrent shift in
fermentation from acetate to propionate – decrease CH4
production.
(Newbold et.al., 1988)

21. Electron Acceptors
 Methanogenesis - lowered by addition of electron acceptors
such as nitrate and sulfate
(Sar et al., 2004)
 CH4 production could be diminished by 10% for each 1%
inclusion of potassium nitrate in a diet.
(Leng, 2008)
 Nitrate - could be used as a nitrogen supplement to low-
quality crop residue-based diets.

22. Bacteriocins
 Bacteriocins are the proteins produced by bacteria that can
obstruct certain microbial species in the rumen
 Nisin (Lactobacillus lactis) stimulate propionate production
and reduce methanogenesis by 36% in vitro
(Callaway et.al., 1997)
 Bovisin HC5 (Streptococcus bovis) – also inhibit CH4 by up
to 50%. (Lee et.al., 2002)
 Bacteriocins inhibit methanogens population in the rumen.
(Sar et.al., 2005)

23. Reductive Acetogenesis
 An alternative strategy to reduce ruminal methanogenesis
could be to redirect H2 from methanogens to acetogens by
reductive acetogenesis pathway.
 Acetogens produce acetic acid by utilizing H2.
4H2 + 2CO2 = CH3COOH+ 2H2O
 Lopez et.al. (1999) found that acetogens depressed CH4
production when added to rumen fluid in vitro.

24. Immunization
 Immunize animals against their own methanogens and
protozoa.
 Antimethanogenic vaccine development - progress.
 Immunization of sheep with a mixed whole-cell preparation
from three methanogens reduced CH4 production by 7.7%
(gms/kg of DMI).
(Wright et.al., 2004)

25. Genetic Selection of Animals
 An alternative to nutritional management is to selectively
breed
livestock that can use feed more efficiently or produce less
CH4 per unit DMI.
(Alford et al. 2006; Hegarty et al. 2007)
 Ruminants with low RFI - Low CH4 emissions - due to lower
methanogens no. in low RFI cattle.
(Zhou et.al., 2009)
 Selection for reduced RFI - lead to substantial and lasting
methane abatement.

26. Number and Productivity of Animals
 Culling of nonproductive and low-producing animals
 Increasing the productivity of animals - also lessen CH4
emissions per unit of products.
 Productivity of animals enhanced - supplementation of
protein and energy to low-quality forages, ionophores,
bovine somatotrophin, probiotics, and proper formulation of
diets.
(Moss et.al.,2000)

27. Conclusion
 Strategies like increased grain feeding, forage processing
& pelleting, organic acids suppl. - not suitable - low cost
production systems.
 Oils and defaunation have remarkable ability to reduce
methane emissions, but fiber digestibility also reduced
significantly.
 Addition of ionophores to ruminant diet offers opportunity to
reduce methane production but rumen microbes can adapt
to them.

28.  Technologies such as plant secondary metabolites,
stimulation of acetogens, and immunization against
methanogens have emerged to lower CH4 production.
 Genetic selection is the area of research with the best
chance of finding a solution – but expensive and long term.
 Vaccination and probiotics are promising approaches for
future research - without any hazard to animal or
environment.

29.  Supplementation of diets with monensin, concentrates, and
UMMB could be cost-effective for high-yielding animals in
Indian situation.
 Until proven and reliable CH4 mitigation technology is
developed, minimizing the number of low producing and
unproductive animals and proper feeding practices with
increasing the number of high-producing animals could limit
CH4 emission without affecting the total production of animal
products.

30. Concluding Remarks
• Mitigation of CH4 emissions can be effectively achieved
by strategies that are cost effective, improve feed
conversion efficiency, improve animal productivity, and
have no potential negative effects on livestock
production hold a greater chance of being adopted by
producers.

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