Irish dairy cow studies on methane production and breed differences in feed-use efficiency

Transcription

1 Irish dairy cow studies on methane production and breed differences in feed-use efficiency Eva Lewis, Frank Buckley, Rob Prendiville, John Murphy, Donal O Brien, Laurence Shalloo Teagasc, Moorepark Dairy Production Research Centre, Fermoy, Co. Cork, Ireland

2 Presentation Overview Ireland and GHG Methane and dairy cows project In vivo work Modelling work Feed efficiency in dairy cows project Current Future

3 Ireland and GHG

4 Commitments to Reducing GHG Ireland has committed to an overall increase of 13% above 1990 levels between the years Overall GHG emissions have increased from 55.8 Mt in 1990 to 68.6 Mt in 2005: 23% In January last year the EU Commission proposed that Ireland must reduce its GHG emissions by 20% below 2005 levels by 2020 It is proposed that all sectors will have to contribute reductions

5 Greenhouse gas emissions Industry Transport Services Residential Unattributed Total Sector Agriculture, Forestry, Fishing Fuel, Power, Water 000 t CO 2 equiv %

6 % of GHG emissions as CH 4, N 2 O, CO 2 in the Agriculture, Forestry and Fisheries sector in Ireland in 2005 % emissions in CO2-equivalents Methane Nitrous Oxide Carbon Dioxide CSO, 2007

7 % of on-farm GHG emissions as CH 4, N 2 O, CO 2 in milk production 80 % emissions in CO2-equivalents Methane Nitrous Oxide Carbon Dioxide Lovett et al., 2008

8 % of on-farm CH 4 emissions from different sources in milk production % of CH4 emissions Enteric Sil Effl Slurry stor Lovett et al., 2008

9 Mitigation strategies for methane emissions by dairy cows in Irish milk production systems

10 Objectives Measure CH 4 emissions by dairy cows grazed grass: differing pre- and post grazing heights supplementation strategies at grass different oil supplements at pasture different breeds and genetic merits at pasture Model effect of these strategies in a life cycle assessment of total GHG fluxes in a pastoral milk production system Provide relevant data to allow adjustment of national GHG inventories

11 Modelling work Land limiting (40ha used, more cows-depends on system) Feed System Strain of Holstein Friesian t CO2 On-Farm t CO2 Total kg CO2 /kg milk kg CO2 /kg MS t CO2 /ha MP HS HC NZ HD HP National cow O Brien et al., 2009, in prep

12 Modelling work summary NZ strain Highest milk solids Highest fertility Lowest liveweight lowest emissions/kg milk solids HP strain Lowest fertility Highest liveweight highest emissions/kg milk and /kg milk solids Work in progress

13 Evaluation of Holstein-Friesian, Jersey and JxHF dairy cows under Irish grassbased spring milk production systems

14 Study overview Three breeds: HF, J, JxHF Measurements Grass parameters: pasture quality, herbage mass, pre- and post-grazing height Animal performance: milk production, BW, BCS, reproductive performance, blood metabolites, DMI, grazing behaviour, health

15 Milk Production Breed Trait HF J HFxJ se P-value Milk yield (kg) 18.3 a 13.8 b 16.7 c 0.32 <0.01 Fat (g/kg) 39.6 a 53.3 b 47.5 c 0.71 <0.001 Protein (g/kg) 34.9 a 40.6 b 38.4 c 0.32 <0.001 Lactose (g/kg) 44.9 a 45.3 a 46.0 b 0.23 <0.05 Milk solids yield (kg) 1.33 a 1.28 a 1.41 b 0.02 <0.05 SCM (kg) 16.9 a 15.7 b 17.5 a 0.30 <0.01 NEL (UFL) 8.11 a 7.45 b 8.32 a 0.14 <0.01 Prendiville et al., 2009, in prep

16 Bodyweight and BCS Breed Trait HF J HFxJ se P-value Liveweight (kg) 498 a 369 b 448 c 4.68 <0.001 NEM (UFL) 5.18 a 4.14 b 4.79 c 0.04 <0.001 BCS 2.76 a 2.93 b 3.00 b 0.03 <0.001 Prendiville et al., 2009, in prep

17 DMI Breed Trait HF J HFxJ se P-value Total DMI (kg) 16.9 a 14.7 b 16.2 c 0.23 <0.05 Energy intake (UFL) 17.8 a 15.6 b 17.1 c 0.24 <0.05 Prendiville et al., 2009, in prep

18 Measures of Efficiency Production/Gross Efficiency Feed consumed : milk output Milk : Body weight Feed : Body weight Net efficiency E contained in the milk over the portion of E used to produce it above maintenance requirements Residual Feed Intake denotes the difference between actual and predicted feed intake (feed intake not accounted for by production and maintenance)

19 Production (gross) efficiency Breed Trait HF J HFxJ se P-value MS/100kg LW (kg) 0.27 a 0.35 b 0.32 c 0.06 <0.001 SCM/100kg LW (kg) 3.41 a 4.30 b 3.95 c 0.07 <0.001 MS/TDMI (g) a b b <0.001 TDMI/100kg LW (kg) 3.39 a 3.99 b 3.63 c 0.05 <0.001 Prendiville et al., 2009, in prep

20 Energetic efficiency Breed Trait HF J HFxJ se P-value RFI (UFL) NS NEI/MS (UFL) 14.1 a 13.0 b 12.5 b 0.32 <0.05 NEI-NEM/MS (UFL) 9.8 a 9.3 ab 8.8 b 0.23 <0.01 NEI-NEM- ADG/MS (UFL) Prendiville et al., 2009, in prep

21 Irish systems Efficiency of converting feed to milk solids is key (under high stocking rates) High grass intake per unit liveweight High milk solids production per kg DMI Without negative consequences for longevity

22 Future research Select high and low efficiency animals from each breed Size and fill of digestive tract Digestibility, site of digestion, rate of passage Rumen function: VFA, ammonia, ph, microflora Methane production N partitioning (milk, urine, faeces) Gene expression (liver, mammary gland, adipose tissue, digestive tract)

23 Many thanks!

24 Irish Net Energy system 1 UFL = NE content of 1kg air-dried barley for milk production Irish NE system UFL(I) 1kg BW loss = 3.5 UFL(I) NE requirement of 4.5 UFL(I)/kg BW gain 1 BCS loss = 150 UFL(I) NE requirement of 200 UFL(I)/kg BCS gain

25 Irish Net Energy system Energy requirements for maintenance UFL(I)/d = BW/100 Energy requirements per kg milk UFL(I)/kg milk = 0.44 ( FC) Energy requirements for pregnancy (40kg calf) 0.9 UFL(I)/d during mnth UFL(I)/d during mnth UFL(I)/d during mnth 9

26 Irish Economic Breeding Index Production Fertility Calving Beef Health Relative Emphasis Year

27 Modelling work Milk quota limiting (70 cows, not using 40ha (land differs), fill quota) Feed System Strain of Holstein Friesian t CO2 On-Farm t CO2 Total kg CO2 /kg milk kg CO2 /kg MS t CO2 /ha MP HS HC NZ HD HP National cow O Brien et al., 2009, in prep