This presentation forms part of the Farming Futures workshop 'Making livestock farming fit for the future' 9th December 2009

1. What Can Improved
Feeding Do To Increase
Efficiency and Reduce
Emissions?
Chris Reynolds, L. A. Crompton,
and J. A. N. Mills
School of Agriculture, Policy, and
Development
15 December 2009 © University of Reading 2008 www.reading.ac.uk

2. “The Perfect Storm”
- Prof. John Beddington 2008
• As the world's population grows, competition for food,
water and energy will increase. Food prices will rise, more
people will go hungry, and migrants will flee the worst-
affected regions. It is predicted that by 2030:
– The world's population will rise from 6bn to 8bn (33%)
– Demand for food will increase by 50%
– Demand for water will increase by 30%
– Demand for energy will increase by 50%
2

3. “The Perfect Storm”
- Demand for food will increase by 50%
www.bbc.co.uk, 2009.
3

4. “The Perfect Storm”
- Climate change will add to the challenge
4

5. livestock’s long shadow
environmental issues
and options
FAO, 2006

6. Ruminant Nutrition
and the Environment
1. Methane – green house gas (GHG)
2. Nitrogen – nitrates, N2O, NH3
Eutrophication, GHG, air quality
3. Phosphorus – eutrophication
4. Manure – all of the above +

7. No Process is 100% Efficient!!
Bill Weiss, The Ohio State University

8. Improving the Efficiency
of Energy Utilization
• Efficiency of feed conversion
– Animal factors
• Efficiency of the production system
– Economic and wider issues
– Life cycle analysis, etc.
8

9. Feed Conversion Efficiency
Linn et al. 9

10. Energy Partition in Ruminants
- 86% of the variation in net energy supply across diets
attributable to variation in digestible energy
10

11. Residual Feed Intake
Berry, 2008.
11

12. Residual Feed Intake
Hegarty et al., 2007.
12

13. Energy Partition in Ruminants
13

14. From The Times
July 10, 2007
How to stop cows burping is the new field work on
climate change

15. Methane Energy Loss
- $$$ and GHG
• Per molecule methane ~25 x
global warming effect of CO2
• Waste of feed energy – 2 to 12 %
• Concern for the ‘carbon footprint’
of milk, beef and lamb
15

16. Where is it from?
Acetate
• Rumen fermentation
yields H2 Butyrate
• Generally N source
Propionate
impacts yield of H2
• Methanogenesis is a Valerate
sink for H2 Microbial growth
•
– C02 reduced to CH4
Fermentation also
occurs in hind gut and
in manure
with amino acids
Microbial growth
with ammonia
H2
Lipid
Hydrogenation
unsaturated fatty acids
H2 Source
Methane EXCESS
H2 Sink CO2 + 4H2 → CH4 +2H2O
Zero pool scheme

17. Ruminant farm animals as
methane producers
• Agriculture contributes
43% to the UK’s
emissions of CH4
• IPCC two sources
– 85% fermentation
– 15% manure
• Proportion is increasing
• Dairy farming accounts
for 30%
• Major target for
mitigation
• Beef and sheep 65%

18. Nitrogen and CH4 Excretion
Studies at Reading
Respiration calorimeters
vs
boxes, head chambers

19. Methane Emission Measurements
SF6 Technique Polytunnels

20. Methane Energy Loss
9
8
Methane/Gross energy intake (%)
7
6
5
4
3
2
0 10 20 30
Dry matter intake (kg/d) Mills et al., 2009. 20

21. Methane Energy Loss
35
30
25
Methane (MJ/d)
20
15
10
5
0
0 10 20 30
Dry matter intake (kg/d)
Mills et al., 2009. 21

22. Methane Energy Loss
0.8
0.6
Methane/milk energy
0.4
0.2
0.0
0 20 40 60
Milk yield (kg/d)
Mills et al., 2009. 22

23. What can we do about CH4?
• Changes at the herd level
– Increasing longevity (reduced culling)
– Extended calving intervals for high producing cows
– Increasing system intensity (more milk per cow)
– Genetics
• Changes to nutrition (~30 L CH4/kg DMI)
– Increase starchy feedstuffs & reduce fibrous feeds
– Increase dietary fat
– Additives
• Yeasts
• Plant extracts
• Organic acids
• Other methods
– Vaccination

24. Herd level actions
• Reduce the overhead of non-producing or low producing animals will
deliver less methane per litre of milk
• Increased health and fertility leading to reduced culling rates
• Extended lactations
• Reduced age at first calving
• Genetic selection for low residual feed intake

25. Nutrition - carbohydrate source
• Methane production is related to intake
– 30 litre/kg DMI
– 8% gross energy intake
• Fibre digestion leads to excess hydrogen and hence
methane
• Replacing a proportion of the fibre with starchy feedstuffs
will reduce methane per kg DMI
• Consider Starch:ADF ratio as an indicator

26. Nutrition - supplementary fat
• Polyunsaturated fats and saturated medium chain fatty
acids (MCFA) are effective
• Unsaturated fats ‘mop up’ hydrogen, but limit fibre
digestion
• MCFA may have less adverse effects on diet
digestibility, whilst still reducing methane significantly
• MCFA present in some oilseeds and coconut oil
– Potential for large reduction with high inclusion

27. Nutrition - additives
• Organic dicarboxylic acids
– Aspartate, malate and fumarate
– Potential propionate precursors
– Compete for available H2 pool
• reduction of fumarate to succinate
– Mechanism: removing H2 stimulates fibre digestion?
– Large dose required for relatively small effect
• 10% reduction in CH4 requires over 2 kg fumarate
• Low rumen pH
• unpalatable

28. Nutrition - additives
• Plant extracts
– Tannins
• Anti-methanogen effect
• Inhibition of fibre degradation
– Saponins
• Anti-nutritional factor
• Defaunation action
• Screening programs underway
– EU programmes

29. Methane Energy Loss
Martin et al., 2009.
29

30. Vaccination
• Immunise against rumen methanogens
• Early stages of application in practice
• Variable results
– Approx 8% reduction in methane
• Further refinements may increase efficacy
– Greater range of antibodies required

31. Future Perspectives
• How can we improve efficiency in ruminant
milk and meat production systems and limit
environmental impacts?
– Improvements in genetics, nutrition, and technology…
• 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
31

32. Thank you
15 December © University of Reading 2008 www.reading.ac.uk
2009