ReynoldsGHGand Ruminants

7/28/2019 ReynoldsGHGand Ruminants

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Effects of dietary feedingstrategies on greenhousegas production by ruminants

University of Reading 2008 www.reading.ac.uk04 July 2013

Chris Reynolds, L. A. Crompton,

J. A. N. Mills, and D. I. Givens

School of Agriculture, Policy, and

Development


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Ruminant Nutritionand the Environment

1. Methane green house gas (GHG)

2. Nitro en nitrates N O GHG NH

- eutrophication, air quality

3. Phosphorus eutrophication

4. Manure all of the above +


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From The Times

July 10, 2007

How to stop cows burping is the new field work onclimate change


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From The Times

July 10, 2007

How to stop cows burping is the new field work onclimate change

From The TimesOctober 27, 2009

Climate chief Lord Stern: give up meat to

save the planet

Methane is 23 times more powerful than carbon dioxide as a global warming gas


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Methane Energy Loss- $$$ and GHG

Per molecule methane ~25 x

global warming effect of CO2

5

Waste of feed energy 2 to 12 %

Concern for the carbon footprintof milk, beef and lamb


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Ruminant Farm Animals asMethane Producers

Agriculture contributes43% to the UKsemissions of CH4 ~ 3 % of total GHG

wo sources

85% fermentation

15% manure

Proportion is increasing

Dairy farming accountsfor 30%

Major target for mitigation

Beef and sheep 65%


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Ruminants and GreenhouseGasses a Hot Topic!!!

7


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Methane Energy Loss

8

Bratzler and Forbes, 1940.


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Nitrogen and Methane

Excretion Studies at Reading

Respiration calorimeters and

digestion trials


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Methane Energy Loss

/d)

25

30

35

10

Dry matter intake (kg/d)

0 10 20 30

Methane(

M

0

5

10

15

20

Mills et al., 2009.


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Where Does Methane Come From?

Rumen fermentation

yields H2

Methanogenesis is a

sink for H2

C02 reduced to

Acetate

Butyrate

Propionate

Valerate

CH4 Fermentation also

occurs in hind gut

and in manure

H2

with amino acids

H2Source

Lipid

Hydrogenationunsaturated fatty acids

Microbial growthwith ammonia

MethaneCO2 + 4H2 CH4 +2H2O

Zero pool schemeH2Sink

EXCESS


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Herd Level Actions to

Reduce Methane

Reduce the overhead of non-producing or low

producing animals will deliver less methane per

litre of milk

Increased health and fertility leading to reducedculling rates

Extended lactations

Reduced age at first calving

Genetic selection for residual feed intake


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Methane Energy Loss

nergy

0.6

0.8

13

Milk yield (kg/d)

0 20 40 60

Methane/milk

0.0

0.2

0.4

Mills et al., 2009.


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Dietary Carbohydrates Methane production is related to intake

On average 30 litre/kg DMI

6.5% gross energy intake (dairy cows)

hence methane

Replacing a proportion of the fibre with starchy

feedstuffs will reduce methane per kg DMI Forage quality (digestibility) important

Consider Starch:ADF ratio as an indicator


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Effect of Forage Type on Methane

Production by Lactating Dairy Cows

30

40

DEFRA Project AC0209

0

10

20

CH4, L/kg DMI

Maize Grass

87%


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Dietary Fat and Methane

16

Grainger and Beauchemin, 2010.


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Supplemental Fat and Methane Supplemental fats reduce methane per unit

feed DMI Supply energy that does not contribute tomethanogenesis

chain fatty acids (MCFA) are particularlyeffective microbial effects?

Unsaturated fats a sink for hydrogen

May limit fibre digestion MCFA may have less adverse effects on diet

digestibility, whilst still reducing methane

negative effects on DMI?


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Effect Of Milled Rapeseed On MethaneProduction By Lactating Dairy Cows

) 500

600

700

18Con x2 RS x2 RS x1 RS4/5 x1

Methane(l

/

0

100

200

300

400

DEFRA Project LS3656


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Effect Of Milled Rapeseed On Methane

Production By Lactating Dairy Cows

MI)

25

30

35

P


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Effect Of Milled Rapeseed On MethaneProduction By Lactating Dairy Cows

ilk) 20

25

Con x2 RS x2 RS x1 RS4/5 x1

Methane(l/kg

0

5

10

15

DEFRA Project LS3656 20


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Effect Of Milled Rapeseed On Milk Fatty

Acid Composition Of Lactating Dairy Cows

00gfa)

60

80

Total saturates

Total cis MUFAs

Con x2 RS x2 RS x1 RS4/5 x1

Milkfat

tyacids(g

/

0

20

40

DEFRA Project LS3656 21


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Predicting Methane UsingMilk Fatty Acid Concentrations

22Dijkstra et al., 2010.


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Dietary Additives Organic dicarboxylic acids

Aspartate, malate and fumarate Potential propionate precursors

Compete for available H2 pool

Large dose required for relatively small effect? Low rumen pH

Unpalatable

Effects in sheep not repeated in dairy cows Nitrites, sulfites, chloral hydrocarbons, etc.


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Feed Additives Plant extracts

Tannins

Anti-methanogen effect

Inhibition of fibre degradation

Anti-nutritional factor

Defaunation action

Extensive screening programs for bioactive plant

components that improve rumen fermentation

Ionophores and other antimicrobials

Adaptation?


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Effect of Supplements on MethaneProduction by Lactating Dairy Cows

25

30

DMI

DEFRA Project AC0209

0

5

10

15

20

Control Glycerol Allicin Naked oats

Methane,

L/kg

P < 0.10


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P < 0.0120

25

lk

Effect of Supplements on MethaneProduction by Lactating Dairy Cows

0

5

10

15

Control Glycerol Allicin Naked oats

M

ethane,

L/Lmi

DEFRA Project AC0209 27


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Nitrogen Inputs and Outputsin Dairy CowsURINE N

37%

N INTAKE

503 g/day

28

MILK N

28%

FAECAL N

33%


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The Nitrogen CycleMilk (and meat)

Purchasedfeed ~25%

~75%

Manure

Soil

Crops

FertiliserN fixation

NH3

Nitrate N2O,NOx

~50%

~50%J. Moorby, 2008


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Nitrous Oxide Emissions: 1990 - 2005


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Nitrogen Excretion in Dairy Cows

urine

milk

faeces

Kebreab et al., 2000.


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Milk N/Intake N versus N Intake

Mills et al., 2009


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Efficiency of Dietary N Utilization

for Milk Protein Production

Milk N as a Percentage of N Intake

30

40%

129% 114% 100%

DEFRA Project AC0209 N intakes lower for grass-based ration

0

10

20

14% CP 16% CP 18% CP

Maize Grass


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16.0

18.0

20.0

22.0

CH4/kg

DM

12.0

14.0

16.0

18.0

4/kgFPCM

Varying NDF quality in grass diets

18 kg DM/d (90% grass & 10% concentrates)

GH GS-EC GS-LC

10.0

12.0

14.0g

GH GS-EC GS-LC

6.0

8.0

10.0gC

GH = grass herbage; GS = grass silage

= high N-fertilization = low N-fertilization

NDF quality & methaneA. Bannink

EC = early cut; LC = late cut

Bannink et al., 2010


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Reducing Greenhouse Gasses Methane numerous dietary approaches

show promise

Dietary carbohydrate and fat have effects Starch:ADF ratio as an indicator

Numerous supplements/additives

Reductions observed in sheep typically notrealized in lactating dairy cows

Nitrates, nitrous oxide and ammonia

Feed less protein how low can we go? Reduced yield may increase methane inventory


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Future Perspectives How can we improve efficiency in ruminant

milk and meat production systems and limitenvironmental impacts?

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mprovemen s n gene cs, nu r on, an ec no ogy

e.g. feed additives, selection indices, etc.

Adoption of best practice in feeding and management

System approaches and assessments The roles of extensive and intensive systems

Must consider wider impacts of specific mitigation options

Exploiting the virtues of ruminants and grasslands

ReynoldsGHGand Ruminants

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