Livestock Methane Emissions

Transcription

1 Livestock Methane Emissions Young Carbon Farmers- Southern Carbon Bus Tour Dr Stephanie Muir Department of Environment and Primary Industries

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3 Australian Policy Context DCCEE 2013

4 Australian Policy Context Agriculture 57% of all methane 75% of all nitrous oxide Enteric Methane 11.5% of National emissions Nitrous Oxide from soils 3.4% of National emissions DCCEE 2013

5 Typical Farm Emissions Dairy 3-7 t CO 2 e/cow 4 45 t CO 2 e/ha 8 21 t CO 2 e/t MS N2O - Indirect 1% N2O - N Fertiliser 0% CH4 - Manure 0% N2O - Dung, Urine 3% 0% CH4 - Enteric 96% Grains t CO 2 e/ha 0.04 t/co 2 e/t grain N-Beef 2 t CO 2 e/au 0.12 t CO 2 e/ha 14 t CO 2 e/t beef Eckard, Grainger & de Klein 2010; Browne et al. 2011

6 Gg CO2e Methane emissions from livestock Enteric CH4 Waste CH4 DCCEE 2011

7 Methane from animal production Largest inefficiency in animal production Methane energy content MJ/kg 6 to 10% of GEI lost as CH 4 Animal Class Methane (kg/year) MJ CH 4 lost /hd/day Effective annual grazing days lost Potential km driven in 6-cylinder car Mature ewe 6 to to to to 90 Beef steer 50 to to to to 800 Dairy cow 90 to to to to 1350 Eckard, Grainger & de Klein 2010

8 Rumen Physiology: basics Rumen, large forestomach of ruminant animals, Fermentation chamber Manure decomposition produces Methane (CH 4 ) Manure and soil produce Nitrous Oxide N 2 O Ammonia NH 3 Fermentation produces Methane, VFA and Ammonia as end products VFA utilised as energy for the cow, ammonia recycled and excreted. 98% Methane released via eructation- Burping Feed consumed by the cow enters the rumen, where is it anaerobically fermented by microbes. Main source of methane is fermentable carbohydrates

9 Methane in the atmosphere: Interacts with long-wave infrared energy to directly affect climate Indirectly influence climate through atmospheric oxidation reactions Global warming potential 21 times Carbon Dioxide 2 nd most important greenhouse gas Enteric fermentation accounts for 10.5% national greenhouse gas emission Methane released via eructation- Burping and from manure decomposition Animal manure and farm soils also produce: Nitrous Oxide N 2 O Ammonia NH 3 From nitrogen in excreta

10 Enteric Methane Measurement In vitro methods Rusitec or artificial rumen Eckard 2009

11 Enteric Methane Measurement Methane from Individual animals in the field using SF 6 Tracer Evacuated yolk/canister Permeation tubes Grainger et al Eckard 2009

12 Enteric Methane Measurement Methane from Individual Animals - Chambers/Calorimeters

13 Enteric Methane Measurement Reflector Methane from herds in the field Open Path Laser & FTIR Wind Reflector Laser Griffiths et al Eckard 2009

14 Factors affecting methane production Less CH 4 Faster rumen passage More O 2 Less methanogens Less H 2 Carbon Acid rumen ph Lower temperature More CH 4 Slower rumen passage rate Less O 2 More methanogens More H 2 Neutral/Alkaline ph Higher temperature Eckard 2011

15 Options for abatement Enteric Methane Technologies to Reduce Enteric Methane Emissions Animal Manipulation Diet Manipulation Rumen Manipulation Animal Breeding Forage quality Biological Control Residual Feed Intake Plant Breeding Bacteriophages bacteriocins Management Systems Efficiency Alternative livestock systems Dietary Supplements Dietary Oils Probiotics Vaccination Reductive Acetogenesis Unproductive Animals Enzymes Chemical Defaunation Dicarboxylic acids Plant Secondary Compounds Tannin & Saponin Eckard 2008

16 Mitigation % Eckard, Grainger & de Klein 2010 Enteric Methane Mitigation Timeline BMPs Dietary Supplements Vaccination Breeding Low Likely Medium Impact High Immediate High Herd Management Timeline Confidence Biological control Silver bullet Rumen manipulation Longer Term Low

17 Enteric Methane Animal Management Reducing unproductive animal numbers Shifting herd/flocks to the business end More meat produced/cow or ewe Higher fertility, early joining, higher weaning % NE = less cows/ewes for same production EI = more meat for same number of cows/ewes Earlier finishing of beef Systems efficiencies Henry & Eckard 2009; Grainger et al. 2008; Eckard et al. 2010

18 Enteric Methane Animal Breeding (medium term) Methanogenesis Genetics can alter rumen biota Heritability ~0.2 Feed Conversion Efficiency Compatible with efficiency gains May only reduce EI not NE Plant Breeding ME: CP ratio High WSC grasses Tannin, oils, fibre Clark et al. 2005; Waghorn et al 2006; Hegarty et al. 2007; Grainger et al. 2008; NLMP 2013

19 Enteric Methane Rumen Metagenomics (long term) New approaches in microbiology Understanding why A genetic blueprint of rumen microbiology in northern beef New microbes identified (digestion without CH 4 ) Raising methane free animals Inhibitory peptides can reduce CH 4 Rapid screening technologies NLMP 2013

20 Potential Dietary Methods to Reduce Ruminant Enteric Methane Production Ionophores (Short term effects only) Dietary Fat Supplements (Variable results) Condensed Tannins (29% reduction in CH 4 ) Specific feed supplements (Grape marc, almond hulls) Specific forages? (Turnips, chicory, plantain, vetch, sainfoin, etc) Other dietary methods? (Nitrate, Sulphur compounds, chlorinated methane analogues) Feeding high amounts of cereal grains

21 Enteric Methane Abatement Diet Supplements Reduction in methane Feed Source g/cow/day g/kg DMI g/l milk Whole Cotton Seed (WSC) Brewers Grain Cold-press Canola Hominy Meal - 3.5% less methane per 1% oil added - CFI Method exists for dairy - Not profitable unless there is an increase in MS Tannin (8.6 g/kg DMI) Tannin 1 (14.6 g/kg DMI) Omega-3 micro algae (DHA) Grape Marc 1. 45% less urinary N Grainger et al. 2007, Grainger et al. 2010; Moate et al. 2010,2011

22 Influence of duration of feeding fat supplements on methane emissions from dairy cows. Diets 1 CON FAT FAT FAT Duration of feeding (weeks) Item Methane (g/cow/day) 500 b 461 a 460 a 467 ab Methane (g/kg DMI) 25.0 b 23.3 ab 22.9 a 23.4 ab Methane (g/l milk) 22.1 b 20.0 a 18.5 a 19.4 a Methane (g/kg F+P) 255 a 242 a 233 a 234 ab Moate et al. 2010

23 Factors influencing methane inhibition by supplementary fat Short term versus long term effect of fat Amount of fat in supplement Fat concentration in pasture Season / Stage of Lactation Saturated versus unsaturated fatty acids Type of fatty acids (eg, plant vs algae oil)

24 Pastures in Southern Victoria typically contain high levels (3 8 %) of crude fat (Ether extract) during Spring and low levels (2 3%) of fat during Summer. Take home message: Feed fat supplements in summer

25 Combined effects Grape Marc Dietary oils 3.5% less CH4 for 1% oil Tannins Up to 20% less CH4 Can we combine these? Raw Oils + Tannins 0% What about naturally? E.g. Grape Marc

26 Feeding Grape Marc 18 to 22% less methane Control Dry Grape Marc Ensiled Grape Marc Total DMI (kg DM/cow/day) Milk (L/cow/day) Methane (g/cow/day) (17% )* 374 (20% )* Methane (g/kg DMI/day) (18% )* 20.1 (22% )* Methane (g/l milk) (14% )* 29.3 (29% )* Moate, Williams, Eckard et al. 201

27 Conclusions and Industry benefits Feeding grape marc to dairy cows Reduces methane emissions by 20% Does not impact substantially on milk production Milk fatty acid profile is healthy Additional research needed with cows in early lactation Any problems? Fungicides?

28 R = 25% R = 28% R = 31% R = 34% R = 25% What has the Australian dairy industry achieved in the last 30 years? Milk(L/cow/year) AusMilk(ML) AusMethane(ktonnes) Methane(g/L)

29 What you can do to reduce methane emissions on your farm Continue doing what you have been doing :- profitable farming with continuous increase in productivity and efficiency Focus on methane intensity (g CH 4 /L milk) Feed fat supplements during summer (if profitable eg. cottonseed meal, canola meal) Maintain high quality leafy-pastures (this increases voluntary feed intake and fat content of pasture) Maintain fertility and health of herd Reduce numbers of un-productive animals