GHG Mitigation Opportunities for Livestock Management in the

U.S.

Shawn Archibeque

Department of Animal Sciences

Today’s plan

• Background on GHGs • Relevant processes for livestock• Mitigation options

– Focus on efficiency– Numerous strategies, few feasible

• Strategic plans for “driving” mitigation changes

Air Quality

• EPA estimates air pollution costs > 22 billion dollars per year

• 1970 Clean Air Act– Criteria Pollutants

• Ozone• Carbon Monoxide• Particulates • Sulfur Dioxide• Lead• Nitrogen Oxides• Recently GHG

New Factors for Animal Ag

• Ammonia (NH3) reporting– EPA plans to regulate – Clean Air Act set forth strict,

cumbersome procedures for regulating pollutants

– EPA is authorized to regulate NOx

– Indirectly regulate NH3 that can deposit and lead to indirect NOx formation

– Huge issue in Colorado- RMNP

Climate Change Legislation

• Key issue for Obama administration• Complicated legislative trail with many

close, but not quite bills• Supreme Court decision Massachusetts v

EPA– Finding CO2 is a pollutant

• Bush administration– >50 cattle required to get permits ($25,000,

$866 million for the industry)– Didn’t pass

Greenhouse gases

• IPCC, 1996• Characterized by their potential radiative

forcing. May change the Eath’s atmospheric energy balance

• Natural emissions• H2O, CO2, O3, CH4, and N2O

• Anthropogenic• Hydrofluorocarbons, perfluorocarbons, sulfur

hexafluorides, H2O, CO2, O3, CH4, and N2O

Greenhouse gases

• Persistence?– EPA (2008) estimates 9-15 years in the

atmosphere

• Net flux

Atmospheric CO2

Photosynthesis

Animals

• Enteric fermentation– Natural process– Byproduct of

fermentation– Primary gases:

65% CO2, 25% CH4, 7% N2, O2, H2, H2S

– Methane is a high energy compound that represents uncaptured feed energy

• Primarily in ruminants

Relevant Processes

• Enteric fermentation– 50-200 L CH4/ beef

animal daily

– 350-590 L CH4/ dairy cow daily

• Primarily in ruminants

Relevant Processes

• Manure emissions– Natural process– Byproduct of

fermentation– Primary gases:

Similar to enteric emissions, but may includes N2O and other compounds

– Environment dependent

• From all animals

Relevant Sources

IPCC

• Tier 1 estimates– Enteric emissions

(kg CH4/year)• Buffalo, 55• Sheep, 5-8• Goats, 5• Horses, 18• Swine, 1.5

IPCC

Feed

lot

Dairy

Other

cat

tle0

1

2

3

4

5

6

7

Ym, %GE

Ym, %GE

• Tier 2 estimates– Class of animal– Primarily a function

of diet– Should be replaced

by country specific data when appropriate.

IPCC

• Manure emissions– Microorganisms in

soil or excreta produce GHG in aerobic and anaerobic conditions

– Occur at:• Point of excretion• Storage• Treatment• Transfer• Land application

Relative contribution to greenhouse gas emission

Energy, 86.4% Solvent and product use,0.1%

Industrial, 4.5%

Agriculture, 6.3%

Waste, 2.7%

EPA, 2007

Methane

Waste water systems,4.7%

Natural gas andpetroleum systems, 26%

Field burning, 0.2%Rice cultivation, 1%

Other non-ag, 4%

Landfills, 24%

Enteric fermentation, 21%

Manure management 8%

Coal mine active/nonactive, 11%

Nitrous Oxide

Agricultural soil management, 77.9%

Field burning, 0.1%

Production/usage, 5.6%

Forest land, 0.3%Manure management, 2.0%

Combustion, 11.1%

EPA, 2007

Enteric Mitigation

• Primary focus is on methane (CH4)

• Four broad sets of practices– Improved diet digestibility

• Primarily through diet selection

– Additives• Redirection or alteration of fermentation

– Improved genetics• Improved degrees of efficiency, longevity,

productivity

– Improved efficiency (Actually all practices influence this)

Diet Digestibility

• Extent of diet digestion, along with the amount will determine precursors for CH4 production

• Changes in VFA production– Grain vs Roughage– Legume vs Grass– Fertilized vs non– Intake– Etc.

Diet Digestibility

• One of the greatest influences on proportion of energy lost as CH4

• Total quantity is influenced by proportion and total energy intake

• Ignores indirect emissions associated with growth of feed

Diet Digestibility

Strategy CH4 % of GE intake

CH4 % of DE intake

Increasing DMI -9 to -23% -7 to -17%

Increasing concentrate:forage ratio -31% -40%

Using fibrous concentrate (beet bulp) vs starch concentrate (barley)

-24% -22%

Rapid (barley) vs slowly (corn) degraded starch

-16% -17%

Forage maturity +15% -15%

Forage species (legume vs grass) +28% -21%

Forage preservation (dried vs ensiled) -32% -28%

Benchaar et al., 2001

Additives

• Many and varied options

• Some have a great deal of research, while others…

• Consistency, feasibility, economics and transient reductions are all issues

• Focus on only a few

Additives

• Ionophores– Lasolocid and monensin

• Initially developed as a coccidiostat • Associated with a decrease in feed intake while

maintaining growth rates• Alters flux of cations across membranes, including

antiport of Na and H cations.• Leads to microbial population shifts that favor

propionic acid production, and a subsequent decrease in methane production

• Effect may be transient in dairy cattle• Typically 10-25% reduction in feedlot cattle• Varied results in cattle consuming high roughage diets

Additives

• Dietary fat– Enteric methane emission (g/kg DMI)

decreased approximately 3.8-6.6% for each 1 % increase in added fat in the diet (Beauchemin et al.,2008; Lovett et al., 2003; Martin et al., 2010)

– Hydrogen sink– Must remain below 8% of diet DM – Implications on fiber digestion

Additives

• CoProducts– Variable results

• 25-30% reduction (McGinn et al., 2009) – 65% forage diet– Fat increased 3% of DM

• No change (Hales et al., 2011)– 10% roughage diet– Fat was equal

– Increasingly used– Readily available

Additives

• Halogenated compounds– Widely studied since 1970s (Johnson, 1972,

1974; Trei et al., 1972; Tomkins et al., 2009; others)

– Generally a greater impact in cattle fed high roughage diets rather than cattle fed finishing diets

– Limited impacts on efficiency/ productivity– Potential toxicity and cost make these unlikely

for routine use

Additives

• Condensed tannins– May serve as a “natural” compound– Some studies have suggested a reduction of

13-16%– Speculated mode of action

• Direct toxic effect on methanogens• Indirectly by modifying intake and diet digestibility

– May also shift N excretion to feces instead of urine (Eckard et al., 2007)

• Potential NH4 and N2O impacts

Additives

• Microorganisms and their coproducts– Viruses and bacteriocins (Klieve and Hegarty,

1999)• Potentially a 50% reduction• Bovicin HC5 from Streptococcus bovis (Lee et al.,

2002)• No adaptation of the rumen microbes over time

– Yeast Cultures– Enzymes– Dicarboxylic acids (acrylate, fumarate, malate)– Under some feeding conditions

Additives

• Immunizations– Vaccination against methanogens– Use animals own immune response– Inconsistent results (Wright et al., 2004;

Eckard et al., 2010)

• Defaunation– Shift to propionic acid production– 26-40% reduction (McAllister and Newbold,

2008; Whitelaw et al., 1984)– 20% for 2 years (Morgavi et al., 2008)

Additives

• Nitro-compounds– Nitropropanol, nitroethane, nitroethanol– Simultaneous increase in hydrogen release– Enhanced when a nitrate reducing bacterium

was added (Anderson and Rasmussen, 1998)

• Others

Genetics

• Cattle selected for improved feed use may have reduced emissions (Hegarty et al., 2007)– Moderately

heritable• 0.28 to 0.58 (Moore

et al., 2009)

– May be dependent on stage of production (lactation vs dry)

Genetics

• Care must be taken for selection of appropriate type of efficiency– Reproductive herd

• Smaller size = less maintenance cost

– Feedlot herd• Tend to select for

larger cattle

Animal Productivity

• In the U.S. most livestock are present in the reproductive herd

• Any assessment of mitigation must balance for production of products

Animal Productivity

• Consider the average cow life cycle– Birth – Weaning – Bred as yearling– First Calf at ~2 years– But what if she is open?– Her calf dies?– She is ill and

euthanized– Reproductive

technologies

Animal Productivity

• Anything that will improve efficiency and reduce days from birth to harvest– Major proportion of

dietary needs are to support maintenance

• No new products• Still similar emissions

to feed consumed for production

• May require a greater growth:maintenance

Animal Productivity

• Managing for improved gain:maintenance may use technologies that may not directly effect the rate or extent of GHG emissions, but are using life cycle reductions as a mitigation process

• Implant strategies• Beta agonists• Spaying, use of MGA• Selection of cattle for

large rate of gain• Management

techniques to improve intake

• Prophylactic disease treatment

• Antibiotic use • Reduced “dry time”

Animal Productivity

• Caution– Animal Welfare– Public Perception– Animal Longevity– Meat Quality– Quality of “Other”

Products???– Other

Environmental Impacts?

Manure Production

• Few measurements of GHG emissions from feedlot or dairy pen surfaces, collection areas, etc.– Climatic factors– Oxidative-reductive

potential– pH– Other chemistry

Manure Production

• Very challenging to measure

• Many techniques that show promise at the bench scale fail at the operational size

• Many techniques are labor intensive or require substantial infrastructure

Manure Happens!

Manure Production

• Focus should initially be on reducing the amount of substrate available for generation of GHG– Grain processing to alter starch digestibility – Dietary fiber– Digestive aids– Appropriate formulation of rations relative to

animal needs

• Only then can management techniques be incorporated

Manure Production

• Greatest impact is driven by the type of management system utilized by an operation– Stockpile– Covering– Composting– Anaerobic digestor– Lagoon– Deep Pit

Composting

• Popular method– Reduction of volume

and weight of manure and other on farm organics (i.e. mortalities)

– Increase in N losses• 1 to 10 % of N lost as

N2O

• Indirect N2O

– Active vs passive• Active 2 x greater CH4

than passive (Hao et al., 2001)

Manure Production

• Capture of emissions– Covering and flaring

• Conversion of CH4 to CO2

• Difficult to measure baseline emissions without the cover and capture

– Anaerobic digester• Huge capital investment• Infrastructure and acceptance by grid• Maintenance of facility• Offset of fossil fuel use

Manure Production

• Manure Handling– Cooling to reduce microbial activity– pH adjustment– Frequent spreading– Alum use– Moisture content– Essential Oils and other plant extracts– Etc.– Many require repeated application, may

increase fossil fuel use

Make it happen

• Incentivize producers– Carbon credits– Branded beef– Others???

• Most technologies enhance productivity– Encourage recognition

of additional benefits associated with improved management techniques

Make it happen

• Emerging carbon credit markets• BIGGS (Bovine Innovative Greenhouse Gas

Solutions– USDA NRCS CIG funding– Working with producers and cattle associations– Emphasis is on technologies that enhance

productivity and reduce days on feed– Near completion– Fewer days where approximately half the NE is

being used for maintenance– Difficulty in verification of reductions (models)

Additional Opportunities

• Branded Programs– Require consumer

support– May indicate that

those not participating are doing something wrong

– Would need extensive education component

Summary

• Greenhouse gas emissions are a natural occurrence associated with living animals

• Many techniques and technologies available to reduce GHG emissions

• Emerging/ change in focus to reduce “emitters” that do not yield a viable product

• Creative methods needed to induce change

Questions?