Methane Emission from Cattle Using GreenFeed. Kirsty Hammond, Garry Waghorn & Roger Hegarty

Transcription

1 Methane Emission from Cattle Using GreenFeed Kirsty Hammond, Garry Waghorn & Roger Hegarty

2 Overview Why we want to quantify enteric CH 4 from cattle Overview of some CH 4 measurement techniques GreenFeed and its ability to measure CH 4 How it works Data generated Duration and number of samples required How it compares to other techniques Detection of treatment effects GreenFeed visitation and animal behaviour Its deployment Conclusions Questions

3 CH 4 Emission Measurements Major agricultural research initiatives are in progress to mitigate enteric CH 4 emissions from ruminants Capacity is needed to measure daily CH 4 production (DMP; g/d) from large numbers of animals for: Inventory verification and mitigation options Animal screening/breeding purposes Assessment of management strategies

4 Appropriate CH 4 Methods for Cattle Will depend on the objectives: Measurements with minimal human interference Applicability under commercial/grazing conditions Required accuracy and precision A lower requirement for specialist knowledge Capability to measure a high throughput of animals Animal ranking/detection of treatment effects Emissions at different times of the day

5 CH 4 From Individual Cattle Respiration chambers (RC) and enclosures Head chambers/hoods/face masks and portable accumulation chambers (PAC) Marker dilution (SF 6 ) tracer technique Short measurements - breath analysis GreenFeed measures quantity ([CH 4 ] x flux) respired Breath CH 4 :CO 2 ratio with estimates of CO 2 emission Sniffers to measure [CH 4 ] in breath

6 6 Accurate CH 4 Measurements: A Challenge but Measuring Intake: A Bigger Challenge Emissions/feed eaten: g CH 4 /kg DMI

7 How the GreenFeed System Works Cows visit GreenFeed for controlled pellet release Pellets dropped at intervals so cows head is in hood for 3-7 min Air is drawn past the cow in the hood; flow is measured and [CH 4 ] and [CO 2 ] with O 2 and H 2 also options Analysis of gas flux includes adjustments for background concentrations, head position, etc. The system is calibrated and drift checked The operator can (remotely) control the system Data includes g CH 4 /d estimated for each 3-7 min, records time of visits, etc.

8 GreenFeed Setup: Indoors and Outdoors

9 CH 4 (g/d) DMP Estimates by GreenFeed for Grazing Cows Over 3 Weeks Dry cows ad lib grazing 2 different winter diets Blue diet: n = 36 cows Green diet: n = 22 cows Aug 19-Aug 24-Aug 29-Aug 3-Sep 8-Sep Waghorn et al. (unpublished)

10 CH 4 (g/d) Diurnal DMP Patterns by GreenFeed for Grazing Cows 300 Dry cows ad lib grazing 2 different winter diets over 3 weeks Blue diet: n = 36 cows Green diet: n = 22 cows Waghorn et al. (unpublished) Hour in day

11 Number of GreenFeed Visits Diurnal Pattern of Cow Visits to GreenFeed Dry cows ad lib grazing 2 different winter diets over 3 weeks Blue diet: 1.8 visits/d (n = 36 cows) Green diet: 1.6 visits/d (n = 22 cows) Hour in day Waghorn et al. (unpublished)

12 Please tell me your exact DMP g/d Repeatability of methane parameters in Respiration Chambers Consecutive days 14d apart <60d d d year DMP Sheep* DMP Cattle# g/kgdm Sheep g/kgdm Cattle # Pinares Patino et al (2013) Animal 7, #:Donoghue et al 2016 this confr

13 Please tell me your exact DMP Repeatability of methane parameters in Respiration Chambers Consecutive days 14d apart <60d d d year DMP Sheep* DMP Cattle# g/kgdm Sheep g/kgdm Cattle

14 How do I know my GF derived CH 4 estimate is right (accurate)? IPCC 6.5%GE

15 How do I know my GF derived CH 4 estimate is right (accurate)? IPCC 6.5%GE Over 22 comparisons (11 SF 6, 9 RCs, 2 models) average difference between GF and other method = 6.5% (S Zimmerman pers com)

16 Even tried and true estimates struggle to be accurate Efficiency with which CH 4 added to the chamber was reflected in the reported methane flux Gardiner, T. D., et al. "Determination of the absolute accuracy of UK chamber facilities used in measuring methane emissions from livestock." Measurement 66 (2015):

17 Sampling Requirements 2 measures/d) Cottle et al. 2015

18 Sampling Requirements 2 measures/d) days Cottle et al. 2015

19 Getting cattle to visit/stay? What is a desirable bait/pellet (rough/conc?) Prior learning & experience Attractants? Learning from others?nz Animal density Generally + Unthreatening introduction & training (quiet & close) Higher uptake in housed animals GF a major source of feed to start Frequency of pellet drops Patience

20 Can the supplement change my emissions? Water Salt (prilled??) Pellets (<10%DMI)

21 Does GF affect grazing Behaviour? Cross over design, 2 x 30ha paddocks Mean daily speed, time spent grazing, time spent travelling, livestock preference index (LPI) for the main grazing area (remainder), stationary Livestock residency index (LRI) and travelling LRI were not altered (P>0.05) by the presence of the GEMs2. Miller J, Schneider D, Holzwart M, Bremner G, Trotter, M and Hegarty R.S. (2015). Grazing behavior of cattle in rangeland grazing system with or without access to a GreenFeed emission monitor. In Recent Advances in Animal Nutrition in Australia: Abstracts of invited papers and posters pp

22 Conclusions GreenFeed: Can quantify DMP from many individual cattle (long term and in various production settings) Does not require additional analytical capability Imposes minor restrictions on animal behaviour Starting to build a consensus on appropriate sampling regime Not all animals become users of GreenFeed Under certain conditions e.g. grazing Need careful calibration and servicing Users (animal and human) trained appropriately

23 Thank you Questions? Thankyou