Lethbridge Research Centre, Lethbridge, Alberta, Canada

International Perspective: Methane Research

Tim McAllister

Gerber et al. 2012

Mtonne CO2e

Total emissions from the global livestock industry

0

500

1000

1500

2000

2500

3000

Beef Cattle Dairy Cattle Pigs Buffalo Poultry SmallRuminants

Enteric CH4 – 39% of total

livestock emissions

Strategies to Lower C-Footprint of Cattle

1) Technology to reduce emissions • Lowering enteric methane

2) Intensification/efficiency

• Increasing milk and meat production (i.e., more food per unit of GHG produced)

Total GHG emissions (CO2 eq)

Unit of product produced

Canada

• CH4 mitigation, N03-,

3NOP, probiotics

• CH4 emissions - feed

efficiency

• CH4 emissions from ILO

• CH4 emission from

manure storage

• Modeling, Holos

• AAFC, Lethbridge; U of

A; U of Guelph; U of M

Canada

United

States

• CH4 mitigation, N03-,

3NOP, essential oils

• CH4 emission from ILO

• Modeling,

• USDA/ARS, Penn State;

Ohio State, UC Davis;

United States

SOUTH

AMERICA

• CH4 - Inventory estimates

• CH4 – relates to feed

energetics

• Embrapa, INTA, INIA

Brazil, Uruguay,

Argentina, Chile

Columbia

EUROPE

• Animal Change

• Ruminomics

• 3-NOP

• Forage breeding

• INRA; Rowett;

Wageningen; Teagasc

Europe

ASIA

• CH4 - Inventory

• Yak

• CH4 - biogas

China, Malaysia,

Vietnam, Indonesia

AUSTRALIA

• CH4 – emissions on

pasture

• CH4 – measurement

methodology

• Low CH4 emitting

genetics

• NO3- blocks

• CH4 – Microbiology

• DPI, CSIRO, U of

Queensland, U of N

England, U of W

Australia

Australia

New Zealand

• CH4 – Vaccine,

chemical inhibitors

• Low CH4 forages

• Low CH4 genetics

• Rumen microbiology

• Global Rumen census

• Hungate 1000

• NZAGRC-PGgRC

New Zealand

Strategies to Reduce Methane Emissions

Diet

Rumen

microbiome and

fermentation

Animal

genetics

photo by Julia Palmer

Methane mitigation effect Long-term mitigation effect Safety

Inhibitors

3-nitrooxypropanol Medium ? ?

Electron receptors

Nitroethane Low No No

Nitrate High No? Yes?

Ionophores Low No? Yes?

Plant bioactive compounds

Tannins (condensed) Low No? Yes?

Saponins Low? No No?

Essential oils Low? No No

Bacterial direct fed microbials Low? No Yes

Defaunation Low No No

Dietary lipids Medium No? Yes?

Inclusion of concentrate Low to medium Yes Yes?

Improving forage quality Low to medium Yes Yes

Grazing management Low Yes Yes?

Feed processing Low Yes Yes

Mixed rations and feeding frequency ? ? ?

Precision (balanced) feeding and feed analysis Low to medium Yes Yes

(Hristov et al., 2013)

Dietary Strategies to Reduce Methane Emissions

CH4 Inhibitor: 3-Nitrooxypropanol

Synthetic compound (DSM Nutritional

Products, Switzerland)

“Clean cow” additive (2018)

Inhibits the reduction of methyl-

coenzyme M to CH4 by methyl-

coenzyme reductase during the last

step of methanogenesis in the rumen

Low safety risk (not carcinogenic or

mutagenic)

Proposed Mode of Action:

3-NOP binds to the active site of the

Methyl-coenzyme reductase

Study Animal CH4 reduction, % Martinez-Fernandez et al. (2014) Sheep 26

Romero-Perez et al. (2014) Beef 33

Haisan et al. (2014) Dairy 42

Haisan et al. (2014) Dairy 60

Reynolds et al. (2014) Dairy 7

Short term studies evaluating NOP

Mode of supplementation

Directly in the rumen

Top-dressed in the feed

Mixed with the feed

Mixed with the feed

Directly into the rumen

Methane emissions of beef cattle fed a 70% forage

diet top dressed once daily with increasing levels of

3-nitrooxypropanol

Romero-Perez et al. 2014 J. Anim. Sci.

24.62a

23.54a

22.33a

16.48b

0

5

10

15

20

25

30

0 0.75 2.25 4.5

CH

4, g

/kg

DM

I

mg NOP/kg BW

33 %

10.75 mg/kg BW = 0.5 g/d; 2.25mg/kg BW = 1.4 g/d; 4.5 mg/kg BW = 2.7 g/d. a,b (P˂0.001).

50

100

150

200

250

300

2 4 6 8 10 12 14 16 18 20 22 24

CH

4, g/d

ay

Time after feeding, h

00.752.254.5

mg/kg BW

Exp. 1. Diurnal pattern of CH4 production from beef

cattle supplemented with different dose levels of NOP.

Treatment P-value1

0 0.75 2.25 4.5 SEM Trt L Q

Dry matter intake, kg/d 12.0a 11.7ab 11.3b 11.4ab 0.89 0.03 0.02 0.07

Total VFA, mM 160.5 159.1 148.4 147.7 9.13 0.16 0.04 0.41

Acetate, mol/100 mol 61.8a 60.8a 56.3b 52.6c 0.99 <0.001 <0.001 0.57

Propionate, mol/100 mol 19.3b 19.4b 21.4b 26.1a 1.16 <0.001 <0.001 0.23

A:P ratio 3.33a 3.23ab 2.74b 2.08c 0.21 <0.001 <0.001 0.76

Rumen fermentation of beef cattle fed a high forage diet

topdressed once daily with increasing levels of 3-

nitrooxypropanol (mg/kg body weight)

Romero-Perez et al. 2014 (

• No effects on total tract digestibility

Effects of feeding 3-nitrooxypropanol continuously for 112 d on methane production of beef cattle fed restrictively

63% 66% 51% 57% reduction

All animals received the

control diet in Recovery

NOP was mixed into the diet (60% forage DM)

(2 g/d)

Shifting H2 Utilization in the Rumen Using Nitrate

Nitrate is reduced to nitrite and then ammonia

Nitrate acts as an alternative H sink, competes with methanogenesis and lowers methane emissions

Source of dietary NPN

Potential for nitrite intoxication

Adaptation needed (gradual increases in nitrate in diets)

Slow release product

Nitrate (nitrite) Toxicity

Nitrate and nitrate can be absorbed into the bloodstream

Nitrite combines with hemoglobin to form MetHb, which is incapable of transporting oxygen to tissues

Mild poisoning: decreased feed intake and production (MetHb > 20%)

Clinical poisoning: brown mucous membrane discoloration, respiratory distress, and finally death (MetHb > 60%)

(Bruning-Fann and Kaneene, 1993)

Full reduction of nitrate to ammonia is a key to

maximizing the effectiveness of nitrate

Materials and Methods

• 8 ruminally-cannulated beef heifers (446 ± 21 kg BW)

• Replicated 4 × 4 Latin square design

• Nitrate source: encapsulated calcium nitrate (EN, 71.4% nitrate in DM; GRASP Ind. & Com. LTDA, Paraná, Brazil)

• Treatments (NO3-, % in dietary DM)

• Control (urea; 0.15 ± SD 0.03 % NO3-)

• 1% EN (0.94 ± SD 0.05 % NO3-)

• 2% EN (1.86 ± SD 0.15 % NO3-)

• 3% EN (2.48 ± SD 0.20 % NO3-)

• 14-d adaptation + 14-d sampling each period and 7-d ‘washout period’ between periods

• Gradual increases in EN in the diet by 1% every 4 days during the adaptation period

Encapsulated nitrate P value

Control 1% 2% 3% SEM TRT EN × h Cont vs. EN Linear Quad

DMI, kg/d 8.6 8.7 8.8 8.4 0.16 0.11 0.64 0.96 0.25 0.044

CH4, g/d 183 177 164 145 5.3 < 0.001 < 0.001 < 0.001 < 0.001 0.001

CH4, g/kg DMI 21.3 20.4 18.7 17.4 0.73 < 0.001 < 0.001 < 0.001 < 0.001 0.44

Enteric methane production

18%

0

5

10

15

20

25

30

35

0 2 4 6 8 10 12 14 16 18 20 22 24 26

CH

4 p

rod

uct

ion

, g/k

g D

MI

Hours after feeding

Control

1% EN

2% EN

3% EN

Enteric methane produced (per kg DMI)

during 24 h in beef cattle fed once daily

Propionibacterium Strain

P-value Variable Control P169 P5 P54

DMI, kg/d 6.50 8.44 7.82 7.73 0.30

CH4, g/d 167 190 181 172 0.66

CH4, g/kg of DMI 25.7a 22.7b 23.5b 22.4b 0.02

Propionate, mol/100mol 20.3 21.3 21.0 20.4 0.72

Methanogens*,108 copies/g 8.46 8.55 8.56 8.30 0.18

Propionibacterium strains ( 5 x 109 cfu) supplemented to growing beef cattle fed a high forage diet (pulse dosed 1X/d)

Direct-fed Microbials: Bacterial Strains to Enhance Propionate Synthesis

Vyas et al. 2014 JAS

Propionibacterium acidipropionici strain P169

Propionibacterium acidipropionici strain P5

Propionibacterium jensenii strain P54

*16S rRNA, qPCR

Percent abundance of total Propionibacteria relative to total universal bacteria in ruminal samples from

beef heifers

0

0.5

1

1.5

2

2.5

3

3.5

4

Control P-169 P-5 P-54

Rel

ativ

e ab

undan

ce, %

Treatments

0 h 3 h

9 h

P = 0.16 (T)

P < 0.01 (H)

P = 0.33 (T × H)

Vyas et al. 2013

Challenge : Supplemented strains of Propionibacteria have a low capacity to survive and integrate into the ruminal microbial community

Still more to learn

Time after feeding

Growing diets (55% silage)

Finishing diets (8% silage)

Methane and pH

Hunnenberg et al. 2015 JAS

CH4

CO2

methanogens

protozoa

H2

H2

Feed

bacteria

fungi

VFA methanogens

Rumen

Volatile fatty acids:

-------> acetate (produces H2)

-------> propionate (uses H2)

-------> butyrate (produces H2)

Methane Production is a Microbially Driven Process

Methanogenesis CO2 + 4 H2 ------> CH4 + 2 H2O

0.0

4.0

8.0

12.0

16.0

Australia, 1981-2010(Wiedemann et al., 2015)

Canada, 1981-2011(Unpublished data)

USA, 1977-2007(Capper, 2011)

30 years ago

Present

Change in GHG emissions per kg of live weight from

Australian, Canadian and USA beef sectors over the

past three decades

Sustainability – definition – everyone is happy?