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Evidence Project Final Report

EVID4 Evidence Project Final Report (Rev. 06/11) Page 1 of 25

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NoteIn line with the Freedom of Information Act 2000, Defra aims to place the results of its completed research projects in the public domain wherever possible. The Evidence Project Final Report is designed to capture the information on the results and outputs of Defra-funded research in a format that is easily publishable through the Defra websiteAn Evidence Project Final Report must be completed for all projects.

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Project identification

1. Defra Project code AC0115

2. Project title

Improvements to the National Inventory: Methane

3. Contractororganisation(s)

IBERSAberystwyth UniversityGogerddanAberystwythSY23 3EB

54. Total Defra project costs £ 3,937,545(agreed fixed price)

5. Project: start date................ 01 November 2010

end date................. 31 January 2014


6. It is Defra’s intention to publish this form. Please confirm your agreement to do so...................................................................................YES NO (a) When preparing Evidence Project Final Reports contractors should bear in mind that Defra intends that

they be made public. They should be written in a clear and concise manner and represent a full account of the research project which someone not closely associated with the project can follow.Defra recognises that in a small minority of cases there may be information, such as intellectual property or commercially confidential data, used in or generated by the research project, which should not be disclosed. In these cases, such information should be detailed in a separate annex (not to be published) so that the Evidence Project Final Report can be placed in the public domain. Where it is impossible to complete the Final Report without including references to any sensitive or confidential data, the information should be included and section (b) completed. NB: only in exceptional circumstances will Defra expect contractors to give a "No" answer.In all cases, reasons for withholding information must be fully in line with exemptions under the Environmental Information Regulations or the Freedom of Information Act 2000.

(b) If you have answered NO, please explain why the Final report should not be released into public domain


Executive Summary7. The executive summary must not exceed 2 sides in total of A4 and should be understandable to the

intelligent non-scientist. It should cover the main objectives, methods and findings of the research, together with any other significant events and options for new work.

This objectives of this project were to generate, under controlled conditions, methane (CH4) emission data from sheep and dairy and beef cattle, from both the animals themselves (enteric emissions) and their manures. These data were required to produce new CH4 emission factors (EFs) for UK ruminant livestock for a new inventory to allow UK government to track the effects of changes in agricultural practices on greenhouse gas (GHG) emissions and for reporting to the United Nations under the UK’s commitment to the Kyoto Protocol. Current reporting relies heavily on Intergovernmental Panel on Climate Change (IPCC) Tier 1 methodologies, which uses default emission factors that are not necessarily appropriate for UK conditions, and which also take no account of factors such as animal breed, diet, and farming system. Development of country- and region-specific EFs allows the use of Tier 2 reporting methods, increasing the precision of GHG inventory calculations, and helping to reduce the uncertainty of current default EFs. This project was highly linked with the other GHG Platform projects, AC0114 (inventory structure) and AC0116 (nitrous oxide emissions). The project consortium was led by Aberystwyth University (IBERS), and included the University of Reading, the University of Nottingham, Scotland’s Rural College (SRUC; formerly the Scottish Agricultural College), the Agri-Food and Biosciences Institute (AFBI), Rothamsted Research North Wyke (NW), and the National Physical Laboratory (NPL). The project management team also included representation from Biomathematics & Statistics Scotland. To ensure the work was industry-appropriate, the project had an advisory board comprising not only representatives from the funding agencies (Defra and the devolved authorities of Wales, Scotland and Northern Ireland) but also representatives from DairyCo, Hybu Cig Cymru, the English Lamb and Beef Executive, Quality Meat Scotland, AgriSearch, and the Livestock and Meat Commission.Early in the lifetime of the project, a literature review was carried out (as part of AC0114) to establish the extent of published information about CH4 production by livestock that was relevant to UK conditions. It confirmed that the plans set out during the commissioning of the project were appropriate, which focussed on sheep and cattle – dairy and beef – and in particular grazing animals, for which there was previously relatively little information. Many of the literature values were for dairy cows fed conserved diets and measured in respiration chambers. Work was carried out with sheep at IBERS, SRUC and AFBI, and as part of experimental work at each site a common breed of the Scottish Blackface was used, and a common diet of dry grass nuts was fed. Work with beef cattle was carried out at IBERS, SRUC and AFBI, and a common breed type of the Limousin crossbred was used. Work with dairy cattle was carried out at AFBI and Reading, and on commercial farms by Nottingham. Some experiments included the collection of manures, samples of which were then sent to NW for laboratory characterisation of the volatile solids components and the methane production potential (B0) of those. All sites working with livestock measured methane production from them in a number of ways, the key component of which was the respiration chamber. A variety of designs were employed, but the common factors for all were collection of expired gases from animals within an enclosed chamber, the measurement of CH4 concentrations in chamber inlet and outlet points, and the measurement of airflow through the chamber. A combination of these measurements enables the calculation of emissions of CH4

on a daily basis (i.e. g/d), and when coupled with measurement of feed intake, CH4 yield (i.e. g/kg feed dry matter (DM) intake) and Ym (i.e. the proportion of feed gross energy excreted as methane energy). A critical part of the project was the calibration of partner chambers by NPL, who released precisely measured quantities of CH4 standards and measured the rate of recovery using the chamber equipment. All data collected from respiration chambers were corrected for these calculated calibration factors, which is a key factor in reducing the uncertainty surrounding the synthesis of CH4 emission factors for the new UK reporting inventory. Most partners also used the sulphur hexafluoride (SF6) technique for measuring CH4 production by free-ranging animals, which comprises the collection of breath samples from animals dosed with a tube from which SF6 permeates at a previously quantified rate. By comparing concentrations of SF6 and CH4 in the breath of these animals, daily emissions of CH4 can be calculated. To ensure consistent methodology across the UK sites, all partners used a common protocol devised by AFBI, and used permeation tubes of SF6 prepared by AFBI. The University of Nottingham used its direct sampling equipment to measure CH4 emissions from dairy cows at milking on commercial dairy farms, and collected data from over 2,000 individual cows, 400 of which were assessed over more than one measurement period to study repeatability. Online sampling was also used in feed bins of beef cattle by SRUC and with dairy cattle using the commercially available GreenFeed system at Reading. Both sites compared the data will more conventional measurements using chambers and SF6.In sheep, much work was done to investigate the effect of breed and breed type on daily enteric CH 4

emissions and CH4 yield from feeds. In general, there was little effect of breed type (including size or weight) on CH4 outputs that was not related to feed intake. Smaller animals tended to eat less than larger


animals, and therefore produced less CH4 per day, but produced the same amount per unit of feed intake. However, body weight was not a good proxy of intake – there was a positive, but relatively poor, relationship between body weight and daily CH4 emissions. Within-genotype differences between improved and unimproved breeding lines of Scottish Blackface sheep were found; high genetic merit animals produced more CH4 (per day and per unit intake) than lower genetic merit animals. Diet tended to have a much greater effect on CH4 emissions, and Ym was affected by diet. On relatively good quality diets, such as improved ryegrass swards, Ym was found to be close to the IPCC default value of 6.5%. On poorer quality diets, such as permanent pasture and upland rough grazing, Ym was lower.In beef cattle, as with sheep, there was limited effect of breed and breed type on enteric CH 4 emissions (daily emissions and CH4 yield from feeds). There was a much greater effect of diet type, with animals consuming more higher-quality (lowland) forage than poorer-quality (upland) forages and consequently producing more CH4 each day on the better quality feeds. Similarly, animals fed concentrate-based diets, compared with those fed high-forage diets, produced less CH4 per day and per unit feed intake, with less effect of cattle breed. Most of the breed effects seen, including effects of beef animal sire, were due to differences in feed intake, sometimes driven by genetic potential for growth.Much previous work has been carried out on enteric CH4 emissions from dairy cows, but little has been done with them at grazing, while dry, or with dairy young stock. In young stock, there was no effect of gender on CH4 emissions, but emissions increased with increasing age as the animals consumed more feed. Increasing the proportion of concentrate in lactating dairy cow diets significantly increased feed intake but had no effect on daily CH4 emissions, so that both CH4 yield and Ym were reduced. No significant effect of feeding a supplemental fat source was found on CH4 emissions from growing heifers, whereas there were significant reductions in CH4 emissions from heifers fed forages based on wild-flower swards, compared to swards of ryegrass, ryegrass/clover and birdsfoot trefoil. Methane yields from feeds were higher from dry cows than from lactating cows, which may be related to the rate of passage of feed through the rumen – a slower passage rate in dry cows may allow the rumen population more chance to ferment the feed and therefore produce more CH4 per unit of feed intake than in lactating cows. Work that investigated the effect of dairy cow breed on CH4 emissions found little effect of breed, as was found for beef cattle and sheep. It is concluded that between-animal variation is greater than between-breed variation.Preliminary synthesis of the new data collected as part of this project reinforces the message that feed intake is the major driver of CH4 production in both cattle and sheep. There are no major effects of gender or breed, and while significant effects of diet can be found within controlled experiments, the effects are less clear across experiments. Physiological state (e.g. dry versus lactating cows) may be important because of changes in digesta passage rates, and this may also contribute to the negative relationship between Ym and feed intake. In other words, as feed intake increases, the proportion of feed energy that is excreted as CH4 reduces. Current on-farm technologies for assessing CH4 production that were used by the project do not appear to be reliable for generating emission factors, because CH4 production data collected by these methods were not found to be related to feed intake. Although the majority of CH4 emissions from ruminant livestock emanate from the gut, a significant proportion can be released from manures, and a major proportion comes from the manures of monogastric animals. Laboratory characterisation of manures collected as part of some of the cattle measurements in this project indicated that the volatile solids components were substantially lower than the default IPCC guidelines values, although the methane production potential (B0) values were similar. In a comparison between pig and cattle slurry in pilot-scale slurry stores, emissions of CH4 and ammonia were higher for pig slurry than for cattle slurry. Acidification of cattle slurry was effective at reducing emissions of both CH4 and ammonia, while the use of floating clay granules reduced ammonia but not CH4

emissions.In conclusion, over a three year period this project generated 1720 new individual mean animal data of enteric CH4 emissions from livestock in controlled conditions: 535 from sheep and 1185 from cattle. An additional 2000+ mean data were generated from cattle in on-farm conditions. Eight different breeds of sheep and 8 breeds of cattle were investigated, and 7 different forage types were fed through sheep and 11 were fed through cattle. This contrasts with the historic database of CH 4 excretion data from cattle only that was brought together for this project from a number of different sources in different countries that contained 2682 individual records and which had taken many more years to produce. This new data will be invaluable for the production of UK-specific emission factors for improved inventory reporting and to enable the UK government to better track the effects of efforts made by UK farmers to reduce CH4

emissions from their livestock.


Project Report to Defra8. As a guide this report should be no longer than 20 sides of A4. This report is to provide Defra with details of

the outputs of the research project for internal purposes; to meet the terms of the contract; and to allow Defra to publish details of the outputs to meet Environmental Information Regulation or Freedom of Information obligations. This short report to Defra does not preclude contractors from also seeking to publish a full, formal scientific report/paper in an appropriate scientific or other journal/publication. Indeed, Defra actively encourages such publications as part of the contract terms. The report to Defra should include: the objectives as set out in the contract; the extent to which the objectives set out in the contract have been met; details of methods used and the results obtained, including statistical analysis (if appropriate); a discussion of the results and their reliability; the main implications of the findings; possible future work; and any action resulting from the research (e.g. IP, Knowledge Exchange).BackgroundAs reported by the UK’s 2011 greenhouse gas (GHG) inventory returns, agriculture accounts for approximately 8% of UK total GHG emissions. The main GHG produced by agricultural activities are nitrous oxide (N2O) and methane (CH4), making up 62% and 38% of direct GHG emissions respectively in 2011. The current UK National GHG Inventory largely estimates emissions from agriculture using the most simplified approach to accounting (Tier 1). This approach uses generic assumptions and factors about livestock management to estimate GHG emissions, and uncertainties associated with the national estimates for GHG emissions from enteric fermentation are approximately ±20% of the estimated annual mean.

The UK Committee on Climate Change has set an intended GHG emission reduction budget of 42% in 2020 relative to 1990 figures. Independently of this, the Welsh Assembly Government has committed to reducing GHG emissions by 3% per year from 2011, with agriculture achieving carbon neutrality by 2020. The Northern Ireland 'Programme for Government' commits Northern Ireland to a reduction of 25% in greenhouse gas emissions and 30% CO2 emissions to below 1990 levels by 2025. Scotland’s Climate Change Act commits to a 34% reduction by 2020, increasing to 42% depending upon future international obligations. In order to achieve these targets, there is a need for the agricultural sector to play a substantial role, and there is an associated requirement to be able to track changes in agricultural activities that result in GHG emission reductions. This necessitates the adoption of more sophisticated methods of measuring, reporting and verifying emissions for inventory purposes.

Under Tier 1 United Nations Framework Convention on Climate Change (UNFCCC) reporting, GHG emission data are compiled using default emission factors (EFs) for the various livestock categories and their manures. This approach effectively uses livestock population numbers multiplied by a standard factor, does not differentiate between standard practices, new or innovative processes, and takes no account of any mitigation practice designed to reduce GHG emissions. The EFs currently used have been generated from published data (cited by the Intergovernmental Panel on Climate Change, IPCC, 2006), and quote 8 kg CH4/head/year for sheep in developed countries (Table 10.10 in IPCC, 2006), and 57 kg CH4/head/year for ‘other cattle’ in Western Europe (Table 10.11 in IPCC, 2006). There is a large amount of imprecision associated with the agricultural GHG inventory, with the current EFs reported as having an uncertainty of ± 30-50%. In order to reduce this uncertainty, and to track the effects of efforts to mitigate CH4 outputs, it is essential to move to the more sophisticated Tier 2/Tier 3 accounting methods, which use disaggregated EFs combined with farm business activity data. Thus, improving the accuracy of EFs will in turn give greater precision to wider evaluations of the environmental footprint of different agricultural systems, and assessments of the impact of measures to mitigate greenhouse gas emissions from livestock.

The overall objective of this project was to deliver a set of emission factors (EFs) for CH4 from different livestock species (focussing on cattle and sheep), breeds and genotypes, under a range of different farm systems and representative business structures. These were generated through a number of measurements within representative breed/system approaches that also assessed the effects of nutrition (basal forages, concentrate supplements, and feed additives), and were applicable to the development of an improved UK greenhouse gas inventory reporting structure.

The specific objectives of this research were:1. To prioritise the knowledge gaps regarding methane EFs from UK cattle and sheep and their

manures (linking to AC0114 Workpackage 2 – mining/exploitation of existing datasets).


2. To develop and standardise novel and high-throughput methods for measuring methane emissions from UK cattle and sheep.

3. To generate, under controlled conditions, methane emission data from sheep (of different breeds and genotypes) maintained on diets representative of a range of UK livestock farming systems, as required to fill current knowledge gaps.

4. To generate, under controlled conditions, methane emission data from beef cattle (of different breeds) maintained on diets representative of a range of UK livestock farming systems, as required to fill current knowledge gaps.

5. To generate, under controlled conditions, methane emission data from dairy cattle maintained on diets representative of a range of UK livestock farming systems, as required to fill current knowledge gaps.

6. To generate, under controlled conditions, methane emission data from manures of animals (cattle, sheep and pigs) maintained on diets representative of a range of UK livestock farming systems, as required to fill current knowledge gaps.

7. To develop new, and refine existing, models (from Objective 1) using novel data (from Objectives 3, 4 and 5), in order to calculate new EFs, to develop methane emission proxies, and reduce the uncertainty surrounding currently used EFs.

8. To disseminate and exchange knowledge generated by this project through publication of results, interaction with peers at scientific meetings, and through liaison with Projects AC0112, AC0114 and AC0116.

The objectives listed above were addressed by the project consortium partners (University of Aberystwyth (IBERS), Agri-Food and Biosciences Institute (AFBI), University of Reading, University of Nottingham, Scotland’s Rural College (SRUC), National Physical Laboratory (NPL), and Rothamsted Research North Wyke (NW)) in eight work packages (WPs) corresponding to each objective.

The outputs from each of these WPs are detailed in brief below. More detail of the work carried out is presented in Appendix A, which includes experimental summaries of the experiments carried out as reports, or in some cases as manuscripts or reprints of publications arising from the work.

WORKPACKAGE 1 – PRIORITISATION OF AREAS REQUIRING EMISSION FACTORSWorkpackage leader: Kairsty Topp, SRUC, in Project AC0114. Partners involved: AFBI, IBERS, NW, Reading, SRUC.The work in this WP was funded and carried out as part of project AC0114 and will be reported in full by that project. The objective of the prioritisation exercise was to identify the amount of knowledge present in the literature and within the archive of project partners that could be used to generate emission factors for the purposes of this project (AC0115), and to identify knowledge gaps that were previously not considered. The CH4 prioritisation report was delivered by project AC0114 in June 2011. An assessment of the existing sum of knowledge applicable to UK conditions drawn up using expert judgement during preparation for this project was for the greatest amount of information being available for housed dairy cows, with less information for sheep and beef animals, and relatively little information for grazing ruminants of all species and type. The more rigorous review process used in the preparation of the CH4

prioritisation report justified the original assessment and the proposed experimental plans for project AC0115.

As part of the prioritisation phase three major existing datasets of individual measurements of energy balance including measurements of CH4 emission across a broad range of diet types, animal characteristics and treatments were amalgamated into a single dedicated Access database containing over 3000 individual observations of CH4 excretion. The dataset covered a broad range of animal characteristics (dairy cows - lactating/dry, breed/genetic merit, parity/stage of lactation; beef - growing/lactating; sheep - mature) and dietary description (mixed conserved diets/grass silage/fresh grass, forage type and proportion, feed quality, feed additives). The extent to which the diet has been characterised varied widely between the different datasets, from values taken from feed tables to individual measurements, and supplemental (meta-) data also varied from extensive to limited.

WORKPACKAGE 2 – METHOD DEVELOPMENT AND ON-FARM VERIFICATIONWorkpackage leader – Tom Gardiner, NPL. Partners involved: AllMost methodologies for measuring CH4 are time-consuming, require specialist expertise and facilities, and are not suitable for routine measurements on-farm. This WP aimed to develop common procedures and validation activities to ensure the results from across the consortium were consistent and comparable. This WP also recognised a need to investigate technology that can be used to measure or estimate CH4

emissions in situ, that is affordable, accurate, reliable and easy to use. It assessed and developed novel technologies that could be used to determine CH4 emissions rapidly and easily in a range of on-farm situations, for experimental and practical purposes. These latter technologies would have potential for on-


farm assessment of CH4 emissions from livestock, as a way of helping to reduce the uncertainty surrounding CH4 emissions derived through inventory calculations using EFs that may not be entirely appropriate for a given set of conditions.

Task 2.1 – Development of the SF6 techniqueThe controlled release and measurement of in vivo SF6 tracer linked to simultaneous CH4 measurements can provide a way to determine the CH4 emission rate from individual free-ranging animals. AFBI led the technique development work, and coordinated knowledge transfer to other participants. This work culminated with a very successful 3 day practical workshop at AFBI in February 2011, where the key issues with the technique were discussed and experience and best practise were disseminated throughout the consortium members. As a result of the development work, a common approach was used across the consortium for the application of the SF6 technique, and this method has provided the primary source of grazing emission data within the AC0115 project.

Task 2.2 – Method standardisationThe work on method standardisation was led by NPL and aimed to ensure that common calibration and validation approaches were being used by all the measurement groups to give consistency in the measurements and related uncertainty budgets. Cross-validation of CH4 concentration measurements was achieved using multiple reference gases covering a range of concentrations. Use of multiple concentrations also enabled sensor linearity to be assessed. NPL prepared a suite of seven CH4

standards with gravimetric traceability back to international standards (and the S.I.) specifically for this purpose. Methane flux validation was carried out using a customised dynamic mixing source that can produce time-varying emission rates with calibrated mass-flow control. Further information is given in Appendix B.

NPL completed chamber validation experiments at each of the 5 chamber facilities being used in the project, and derived calibration adjustment factors for each facility together with the associated uncertainties. While the primary goal of the experiments was to determine the absolute accuracy of the emission measurements, the experiments were designed to allow the key components of each facility to be separately tested facilitating identification of the areas of greatest uncertainty and recommendations for future development. In addition to the absolute calibration experiments a series of further tests were carried out to assess key aspects of the measurement system including sensor response time, chamber response time and concentration stability. Whilst these parameters do not always directly affect measurement accuracy they can influence experiment design and system optimisation. The chamber calibration factors have been applied to the livestock emission results from the other experimental WPs, to establish the overall consistency and accuracy of the AC0115 data.

Another area of activity under Task 2.2 has been on grazing intake. As the expected primary output from the project will be CH4 emission as a function of intake (with potential modifying factors such as breed and feed type), the consistency of the intake data (and related uncertainties) is therefore as important as the CH4 emission data. A grazing intake workshop was organised at SRUC involving all of the relevant groups. This proved to be a valuable open forum to highlight the issues and experience found across the project consortium and beyond.

Task 2.3 – LaserMethane detectorSRUC and IBERS have assessed the use of a ‘LaserMethane’ system to directly measure CH4

concentrations around the animal’s mouth. The method uses infrared laser absorption spectroscopy to provide a measure of the path-integrated CH4 concentration between the hand-portable instrument and the solid target it is pointed at. The technology was originally developed for the detection of natural gas leaks and has only recently been applied to animal emission measurements.

Such measurements have the potential to be useful for screening large numbers of animals, ranking animals used in chamber work, and assessing population distributions. The AC0115 research has confirmed the capability of the method to provide non-contact, non-invasive measurements of enteric CH4

emissions in individual animals and providing data on the short-term variability in CH4 emissions. However, it has also highlighted the need to discriminate between respiration peaks (low concentration/continuous) and eructation events (high concentration/occasional), and that background measurements are important in order to establish and account for ambient CH4 concentrations and instrumental variability.

Task 2.4 – Absorption spectroscopyA range of advanced optical remote sensing methods were deployed by NPL at the University of Reading CEDAR facility in early October 2013. An infrared differential absorption LIDAR system was used to remotely map the CH4 emissions from the dairy cattle and an open-path Fourier transform spectrometer was used to provide simultaneous multi-species measurement along defined atmospheric paths. A subset


of the herd was monitored by the GreenFeed system, which was operated by the University of Reading during the campaign.

Task 2.5 – SniffersA number of groups are using ‘sniffer’ technology in feed bins and milking areas, potentially providing data appropriate for wider population screening and animal ranking. Direct online (sniffer) sampling is being used at SRUC and the GreenFeed system at Reading. The GreenFeed system is a commercially-available automated head chamber unit used to estimate emissions from free-ranging animals. In addition to measurements obtained using respiration chambers and SF6 dilution, companion measurements of CH4

emission using the GreenFeed system were obtained in all but the first of the WP 5 experiments at Reading (described below). Overall, estimates of CH4 emission by growing heifers using GreenFeed were comparable to values obtained by respiration chambers, but only 0.89 of the SF6 technique. This may have been attributable in part to a lower number of visits to GreenFeed during grazing measurements, or the timing of the visits. Overall, the variation associated with measurements of CH4 emission was higher for GreenFeed than for SF6 or respiration chambers. The GreenFeed system is capable of estimating CH4

emissions from growing and lactating dairy cattle, but deployment and replication must be considered carefully to ensure a sufficient number of CH4 estimates are obtained.

Nottingham University are using direct sampling during milking to monitor CH4 emissions from dairy herds and now have over 2,000 cow measurements in their primary database, including repeat measurements on 400 cows to assess repeatability over time. Testing of the technique showed a significant correlation with emissions measured in chambers, and a linear relationship with milk yield for individual animals, although the variation between animals was high. This work concluded that the method could provide a low-cost reliable method to estimate daily CH4 output by individual dairy cows, which could be used to study variation in CH4, to identify cows with low emissions, and to test outcomes of mitigation strategies.

WORKPACKAGE 3 – METHANE EMISSION MEASUREMENTS FROM SHEEPWP leader – Mariecia Fraser, IBERS. Partners involved: IBERS, SRUC, AFBISheep production in the UK is generally stratified into systems that utilise smaller, hardier breeds in the hills, their crossbreds in the uplands, and heavier, more productive breeds and their crossbreds in the lowlands, with significant differences in the national/regional breed/system mix depending upon the large variability in land type. With an absence of UK-specific EFs for any region of the UK there was an urgent need to develop and refine these. The work outlined below collectively covered current and emerging flock structures, key stages of the sheep production cycle, and regional differences in farming systems. Connectivity across research centres was strengthened by the inclusion of a common breed (the Scottish Blackface; the most numerous breed in Britain, well represented on the ground in England, N Ireland and Scotland) and a common diet (grass nuts from a single supplier). For the grazing studies each of the research centres worked with semi-natural pasture types that have particular regional significance, but which are found across the UK. Thus the combined data set includes those vegetation communities which collectively account for the bulk of grazed land in the hills and uplands across the UK.

Task 3.1 – Effect of body size on methane emissions from sheepThis series of studies tested the hypothesis that body mass and associated allometric relationships, rather than breed type, determines enteric CH4 production regardless of sheep age or stage of maturity. In the first set of experiments CH4 emission measurements were made on barren ewes of four different breed types: Welsh Mountain (WMO), Scottish Blackface (SBF), Welsh Mule (WMU) and Texel (TEX) (n = 8 per breed). A range of live weights from 40 to 80 kg was recorded across the four breed types. Data were initially collected during three separate zero-grazing experiments in which the animals were offered fresh herbage cut from: 1) an intensively managed perennial ryegrass sward, 2) a long-term permanent pasture and 3) Molinia-dominated rough grazing. Following an adaptation period of at least three weeks the ewes were individually housed in one of four calibrated respiration chambers and data were collected for three consecutive days for each individual animal. The results indicated that regardless of pasture type ewe LW is a relatively poor predictor of CH4 emissions. Breed type only affected the amount of CH4 emitted per head per day when the ewes were offered the Molinia, and the lower CH4 for the WMO ewes relative to the TEX ewes when offered this forage mirrored breed differences in DMI. Thus there was no difference in the amount of CH4 emitted per unit intake, or the percentage of feed energy lost as CH 4. There was a stronger relationship between DMI and CH4 emitted. A follow-on study with the same ewes tested the relationship between live weight and CH4 emissions when they were fed to maintenance requirements on grass nuts (the common diet). Even when intake of grass nuts was restricted to maintenance requirements, and thus appetite and selective feeding did not influence the results, between-animal variation in CH4 emissions was still comparatively high.

During this first series of experiments the animals were housed in CH4 chambers and zero-grazed in order to minimise potential confounding of differences in enteric CH4 production with differences in grazing behaviour. A second series of experiments then investigated the extent to which body size determines


CH4 emissions from ewes foraging on swards differing in structural complexity and the opportunity they offer for selective grazing. Methane emission measurements were made on barren ewes of the same four breed types: Welsh Mountain (WMO), Scottish Blackface (SBF), Welsh Mule (WMU) and Texel (TEX) (n = 8 per breed). Data were collected during three separate experiments in which the animals were grazed on: 1) perennial ryegrass (pilot study), 2) a long-term permanent pasture and 3) a hill sward consisting of a mosaic of improved and unimproved grassland. Each experiment consisted of an adaptation period of at least three weeks followed by a measurement period when CH4 emissions were estimated using the SF6

technique. Although the WMO had the lowest total daily CH4 emissions when grazing the permanent pasture, the amount they emitted per unit DMI was numerically highest, as was their CH4-E/GEI (Ym). The WMO also had the lowest daily CH4 emissions when the ewes grazed the hill sward, but on this pasture type it was the WMU that had the lowest CH4 output per unit DMI and the lowest Ym. Overall, a positive but relatively poor relationship between bodyweight and CH4 emissions was found at grazing.

A third set of experiments investigated the extent to which breed x diet relationships for growing lambs are explained solely by simple body weight and digestibility characteristics of the animal and diet respectively, with no interactions. Methane emission measurements were made on weaned lambs of two different breed types (n=8 per breed): purebred Welsh Mountain (WMO) (small, hardy, hill breed) and Mule x Texel (TEX-X) (prime lamb). Methane emissions were determined when the lambs were housed in CH 4

chambers and zero-grazed on material cut from contrasting high (ryegrass) and low (permanent pasture) digestibility pastures, as well as when offered a reference diet of grass nuts. Although total daily CH 4

emissions were higher for the TEX-X lambs compared to the WMO lambs (P<0.05) when offered fresh forage, the yield of CH4 per unit DMI was similar for the two breed types. Total output of CH4 per day was higher when offered ryegrass compared to permanent pasture (P<0.001), but CH4 emissions per unit of DMI and Ym were higher on the permanent pasture (P<0.01). There were no forage type x breed type interactions identified. Overall the results mirror those found for the mature ewes, indicating that forage type had a greater impact on CH4 emissions than breed type.

Task 3.2 – Effect of within-breed genotype on methane emissions from sheepThis task investigated the effect of contrasting sheep genotypes, with the objective of measuring CH4

production from hill ewes within breed. This tested the hypothesis, linked to Task 3.1, that differences in CH4 EFs created through breed selection for improved performance are relatively small at the individual breeding ewe level, but could scale up through variation created in production characteristics (lambs produced, longevity) to create meaningful differences at the system, farm, national levels. Methane produced by grazing ewes (n = 48), with single lambs at foot, was measured using the SF6 method, providing a maximum of 8 records per ewe over a two-week period. The experiment was a 3x2 factorial, continuous design experiment with 3 genotypes (Mules, Scottish Blackface with high estimated breeding values (EBVs) for maternal ability (SBF_H), Scottish Blackface ewes with low EBVs for maternal ability (SBF_L)) and two sward types (lowland reseeded pasture and a fenced area of rough hill grazing on semi-natural grassland sward). Maternal ability was defined as the average weight of lambs weaned by the ewe. After eliminating unreliable data records (79% of records), 80 records remained, from a total of 36 ewes. Generalised linear mixed model regression analysis found a significant effect of ewe genotype on CH4 production, when expressed as grams per day (SBF_H > SBF_L), or grams per kg dry matter intake (SBF_H > SBF_L and Mules) as estimated by back-calculation. For the SBF ewes, maternal ability EBV had a significant (positive) effect on CH4 production. Scottish Blackface ewes with high genetic merit for maternal ability produced more CH4 than Scottish Blackface ewes with low genetic merit for this trait, when measured using the SF6 method during lactation, rearing single lambs, on hill or lowland pastures. Hill and lowland environments did not differ significantly in their effects on CH4 production (g/d), until it was adjusted for dry matter intake, when results then differed depending on the model used to obtain feed intake values using back-calculation.

A winter feeding experiment with the same genotypes was also conducted. Methane emissions were measured in respiration chambers from pregnant ewes (between 60 and 80 days gestation) fed one of two diets: ad libitum forage or dried grass nuts. Mules, SBF_H, and SBF_L were again compared. Therefore, the experiment had a 2 (diet) x 3 (genotype) factorial design. The ewes (n = 48) were housed in chambers in matched pairs, to ensure high enough CH4 emissions for accurate measurement, and results divided by two to produce 24 records (8 per genotype). Significant effects of diet (grass nuts > forage) and genotype (Mules > SBF_L) were found for grams of CH4 produced per day, but these differences were lost when CH4 production was expressed relative to intake of dry matter or gross energy. The results suggest no within-breed or across-breed differences in CH4 production, after adjusting for dry matter or gross energy intake.

Task 3.3 – Effect of cross-bred genotype on methane emissions from sheepThe objective of this task was to generate baseline data on CH4 emissions from purebred Scottish Blackface and crossbred hill ewes and their offspring on a range of forage types. Using sheep chambers which were be constructed for this project enteric CH4 emissions were measured from a total of 58 lowland


replacement ewes, 72 hill replacement ewes and 23 lactating hill ewes and their lambs over 2 or 3 periods and using 2 or 3 breeds per period depending on the study. The sheep were offered either grass nuts (GN) or a diet representative of current standard practice, i.e. fresh grass (G) in the summer and grass silage (GS) in the winter. Within each period, there were no significant differences between breeds in terms of DMI, CH4 emissions (g/d) and CH4 output per DM intake (DMI) and GE intake (GEI) for both lowland and hill replacement ewes. Hill and lowland replacement ewes offered GN had higher LW, DMI (P < 0.001) and CH4 emissions (g/d) (P < 0.001), but lower CH4 output per DMI and per GEI when compared to those given G or GS. Ym values for replacement ewes offered fresh grass were on average 5.7% for hill ewes, which is lower than the value currently used (6.5%), and 7.3 and 6.9% for 8 and 19 month old lowland ewes respectively, which is higher than the default value currently used (6.5%). Emissions for the hill replacements were similar when fed grass silage or fresh grass, hill or lowland grass. When fed similar forage types, CH4 emission factors were similar between age groups.

WORKPACKAGE 4 – METHANE EMISSION MEASUREMENTS FROM BEF CATTLEWP leader – Tony Waterhouse, SRUC. Partners involved: SRUC, AFBI, IBERSAs with sheep, there was a paucity of CH4 emission data for beef cattle, particularly on fresh/grazed diets, and no-UK specific EFs are currently used in GHG inventory reporting. Existing data were based on housed, finishing beef cattle offered silage-based diets, and thus information was required on emissions from grazing animals, suckler cows and different breeds and genotypes. There was also a lack of data on CH4 emissions from animals grazing vegetation located in LFAs of the UK. In non-LFA areas further information was required on CH4 emissions from different improved sward types and alternative forages. The effect of genotype (and in particular offspring from the dairy and beef herd), linked to system, on CH 4

emissions also needed quantifying. In common with sheep there is a multitude of different breeds and crosses used in British beef systems with different body weights, intakes, and finishing timescales. A G(enotype) x N(utrition) experimental programme at each centre formed the focus and linkage for the work across the project consortium. Each centre had separate self-standing experimental programmes, but these combine to link suckler cow comparisons (SRUC and AFBI), finishing cattle (SRUC and AFBI) and breed type x diet comparisons (SRUC, AFBI and IBERS). The work shared a common theme through use of the Limousin crossbred animal, the most common beef genotype used by producers in both ‘dairy’ beef systems and in more specialist beef breed systems.

Task 4.1 – Effects of suckler cow breed on methane emissions This work had the objective of measuring CH4 production from representative genotypes of beef suckler cow during two phases of production: summer with cows at grass (with calves at foot), and winter with housed dry cows. Comparisons were made between the industry standard of Limousin cross cows (as the control type) with a modern beef composite breed (Stabiliser), and a traditional slower maturing hill type breed (Luing).

Non-lactating dairy-bred suckler cows of two genotypes (Limousin x Holstein-Friesian and a composite breed the Stabiliser) were used to study enteric CH4 emissions and energy and nitrogen utilization from grass silage diets at AFBI. There were no significant differences between the genotypes for energy intakes, energy outputs or energy use efficiency, or for CH4 emission as a proportion dry matter intake or energy intake or for nitrogen metabolism characteristics. Methane energy output was 6.6% of gross energy intake. There was no significant effect of suckler cow genotype on the efficiency of energy use, enteric CH4 emissions or N outputs.

Non-lactating pregnant suckler cows of contrasting breeds (Limousin cross and Luing) were fed on contrasting diets at SRUC, one based on a straw-silage diet, the other on straw and brewers grains. Although both breeds of cattle showed higher DMI on the straw-silage based diet than the straw-brewers grains diet, neither this nor slightly higher CH4 outputs were significant. No significant breed differences were identified the current study. The high oil content of brewer’s grain diet linked to lower CH4 yield.

For lactating suckler cows of different genotypes on contrasting sward types, hill versus lowland, no breed/genotype differences were found in CH4 outputs regardless of pasture type. Total daily CH4

emissions were less on the hill pasture but this difference was considered to be due to pasture digestibility. In another study, aimed to link up measurement technologies, outputs of CH 4 were only weakly correlated with cow size.

The core conclusions of this task area are that there are no major breed impacts upon CH4 production. Breed can influence intake and animal performance, and across different diets, particularly upland grasslands, there is scope to some breed differences in CH4 output to be linked to differences in animal behaviour, intake and potentially physiology.

Task 4.2 - Effects of breed type and diet on methane emissions by growing and finishing stockThis task utilised contrasting breeds/genotype across contrasting dietary resources, both housed and


grazed, to study CH4 outputs.

Work with grazing cattle at IBERS using the SF6 technique directly compared emissions from two contrasting breed types (Limousin sired, Belgian Blue x dairy crossbred - a large, fast-growing modern breed type and Welsh Black - a smaller, slower growing traditional breed). Swards of contrasting quality and complexity (an intensive perennial ryegrass sward and semi-improved hill sward) were grazed. There was no effect of breed type on CH4 emissions when grazing the ryegrass, but when grazing the hill sward CH4 emissions from the Limousin-cross steers were significantly higher than those from the Welsh Blacks. Emissions per unit of dry matter intake were similar for the lowland and upland systems, but CH4

emissions per unit of live weight gain were substantially higher when growing cattle graze poorer quality pasture, and the results indicate that breed type has the potential to influence CH4 emissions when cattle graze such swards.

Growing cattle of contrasting genotype used pasture of contrasting types at AFBI. Friesian steers, Charolais cross steers and Charolais cross heifers were grazed on either improved perennial ryegrass dominated pasture or upland semi-natural hill swards. No significant differences for genotype were reported. The more efficient use of the higher quality improved pasture resulted in less CH4 per kg of live weight gain than for similar cattle grazing the upland pasture. There were similar CH 4 emissions per kg of dry matter intake between the two pasture types. The results of this study are supported by further studies with zero grazed growing cattle fed three contrasting pasture types (upland, upland well grazed and lowland) and greater output of CH4 per kg dry matter intake was exhibited with the lowland grassland compared to the upland types.

For housed finishing trials at SRUC, trials focussed on genotype differences with the first between different, but arguably similar breed types, with weaned suckled calves sired by either Aberdeen Angus or Limousin bulls and the second trial between more contrasting breed types – Charolais-sired crossbred and purebred Luing suckled calves. In the first of these trials, there were clear and significant effects of diet, with substantially lower CH4 emissions, both total and per unit of feed input for the concentrate diet. There was also a small, but significant difference in CH4 emissions between the breeds, with the Aberdeen Angus and Limousin sired producing 184 g/d and 164 g/d respectively. This difference between breeds in daily CH4 emissions can be linked to higher growth rates and higher feed intake and there were no significant differences between breeds for CH4 emissions expressed per kg of intake or per unit of growth rate. Substantially larger variation in means between sire groups was obtained than the significant differences between breeds. In the second trial with Charolais versus Luing, CH4 production was also substantially reduced on the concentrate diet, both in terms of gross output and per kg of intake and growth rate and there were no differences between breeds. In this case, no significant differences between sire groups can be reported.

Overall, breed/genotype had only limited impacts upon CH4 emissions. Where differences in total CH4

emissions were found, these were related to differences in feed intake, and in terms of units of CH 4 per unit of feed intake typically there was no breed effect. Diet type had a much clearer impact with upland grassland having lower intakes (measured and estimated) of lower quality grassland, leading to lower levels of CH4 output, but when calculated per kilogram of intake there are small differences and when calculated per kilogram of growth rate then lower emissions from the poorer quality pasture or diet. All concentrate diets had lower emissions in total and per unit of intake or production, as expected. Where differences in breed were obtained, there were no clear interactions between breed and diet, though for hill swards, adaptation to diets and environment may play a role.

WORKPACKAGE 5 – METHANE EMISSION MEASUREMENTS FROM DAIRY CATTLEWP leader – Conrad Ferris, AFBI. Partners involved: AFBI, ReadingA review of the literature carried out by the GHG Platform highlighted that dairy cows are the livestock group for which the most CH4 emission data were available, although the majority of these data have been derived from housed cattle offered diets based on conserved forages. In many parts of the UK dairy cows and dairy young stock graze for between 6 and 10 months of the year. However, there had been very few measurements of CH4 output available for grazing dairy cattle within a UK context. While measurements have been undertaken within other countries, herbage quality and grass/forage species, level of dietary supplementation and milk yield potential of cows (all of which affect dry matter intake) are all likely to be key drivers of CH4 production in a grazing animal. For this reason direct measurements of CH4 production were required to be undertaken within grazing scenarios representative of typical UK dairy systems. There was also little information available on effects of dietary, animal and management factors on CH4

emissions from young cattle and dry cows, which in turn impacted upon the accuracy of the CH4 emissions inventory for UK livestock. The aim of this WP was to generate new experimental data that can be utilised to improve CH4 emission factors for dairy cattle within the UK GHG inventory. Specific objectives focused on quantifying CH4 emissions from grazing dairy cattle (lactating, growing, dry), growing dairy cattle and mature, dry dairy cattle. Some of the measurements involved direct comparisons of dairy and beef young


stock, on similar diets, to identify if a single emission factor is appropriate for both growing dairy and beef young stock of similar ages/live weights.

Task 5.1 Methane emissions from mature dairy cows while grazing: Three experiments were undertaken at AFBI to examine CH4 emissions from mature dairy cows while grazing, with emissions in all studies measured using SF6 dilution. The first experiment involved 40 Holstein-Friesian dairy cows, and examined the effect of concentrate feed level (2.0, 4.0, 6.0 and 8.0 kg/cow/day; fresh basis) on CH4 emissions across four measurement periods. Concentrate feed level (2.0, 4.0, 6.0 and 8.0 kg/day) had no effect on daily CH4 emissions (287, 273, 272 and 277 g/d, respectively: P = 0.524), while CH4/kg DMI (20.0, 19.3, 17.7 and 18.1 g/kg, respectively; P = 0.005), CH4/kg energy corrected milk yield (14.1, 12.5, 11.4 and 11.1 g/kg, respectively: P<0.001) and CH4-E/gross energy intake (5.9, 5.7, 5.3 and 5.4%, respectively; P = 0.015) decreased with increasing concentrate feed level. Thus, provided an adequate milk yield response is obtained, increasing concentrate feed levels is one strategy by which to reduce CH4 emissions/unit of milk with grazing cows. The second experiment, a 2 × 2 factorial design experiment (factors examined comprised two dairy cow genotypes [Holstein-Friesian and a ‘three-way’ crossbred comprising Swedish Red × Jersey × Holstein-Friesian: 20 cows of each genotype] and two concentrate feed level (3.0 and 6.0 kg/cow/d) was designed to examine if emissions from cows of different genotypes differed. Increasing concentrate level had no significant effect on daily CH4 emissions (P = 0.177), CH4/kg DMI (P = 0.058) and CH4/kg energy corrected milk (P = 0.120). Crossbred cows had higher daily CH4 emissions than Holstein cows (P < 0.05), while CH4/energy corrected milk (g/kg) was unaffected by genotype. There were no interactions (P > 0.05) for any of variables examined. Thus at similar stages of lactation and milk yields, and, there was no evidence of differences in CH4 emissions between genotypes. The third experiment was conducted to provide information on CH4 emissions from non-lactating pregnant (‘dry’) dairy cattle while grazing. Emissions were measured from a total of 68 dairy cattle during three successive years. Total CH4 emissions were 206 and 221 g/cow/day for primiparous and multiparous cows, respectively, while the corresponding values for CH4/DMI were 25.6 and 25.1 g/kg, respectively. A range of prediction equations for CH4

emissions were developed within each of these experiments, while the combined data sets provide scope to allow the impact of milk yield, stage of lactation and live weight to be modelled for grazing cows.

Task 5.2 – Methane emissions from growing dairy cattleAt Reading, two Latin square design experiments were conducted to determine effects of conserved forage type (maize vs grass silage) and supplemental fat (extruded linseed) on CH4 emissions and energy and nitrogen balance of growing dairy heifers with two live weight ranges (382 to 526 and 292 to 419 kg) using digestion trials and open-circuit respiration chambers. In both experiments, supplemental fat had no effect on CH4 production (g/d) or yield (g/kg DMI), but the amount of fat fed was lower than in previous studies. Methane yield was lower when maize silage was fed to heavier heifers of experiment 1, but forage type did not affect CH4 yield in the lighter heifers used in experiment 2. This may be due to differences in forage composition and quality and/or effects of relative body size on rate of digesta passage from the rumen. A further two experiments were undertaken at Reading to investigate effects of feeding multi-species forages on CH4 emissions of growing dairy heifers. Small bale haylage was conserved from swards differing in forage species: a perennial ryegrass control, ryegrass with red clover, ryegrass with lotus, and ryegrass with a wildflower mixture. Using a 4 x 4 Latin square design experiment with 5 week periods, 4 heifers were fed the haylages for approximately 0.75 kg/d LW gain, averaging 344 to 436 kg LW. The following year, 12 growing heifers (230 kg average initial LW) sequentially grazed the control, red clover, and wildflower swards on 2 occasions for 4 week periods and CH4 emissions were estimated using SF6 dilution. In both experiments, CH4 production and yield were lowest for the wildflower sward. However, diet digestibility, energy balance, and nitrogen balance were also lowest for the ensiled wildflowers. The substantial negative effect of the wildflowers on protein digestion is a particular concern, and may be attributable to secondary plant compounds or protein quality.

Two AFBI experiments examined CH4 emissions from growing Holstein Friesian dairy young-stock. In the first of these, the SF6 dilution technique was used to measure CH4 emissions from 36 grazing heifers (calves, yearlings and in-calf heifers: 12 of each) in mid-season (May – July) and from a further 36 grazing heifers in late season (August – October). Daily CH4 emissions from calves, yearlings and in-calf heifers were 98, 189 and 172 g in mid-season and 106, 155 and 169 g in late season, respectively, with emissions from calves lower than from yearling and in-calf heifers during both measurement periods (P < 0.001). Methane per kg LW0.75 was significantly higher (P < 0.001) for yearling than in-calf heifers during both measurement periods, while yearlings also produced more CH4/kg LW0.75 than calves in mid-season (P<0.001). Methane per kg of DMI was greater (P < 0.001) for yearlings in mid-season but not late season. Methane energy, as a proportion of GE intake, was higher in yearlings than calves in both mid (P<0.001) and late season (P<0.05). This study provides useful information on CH4 emissions from grazing dairy heifers during the rearing period.

The second AFBI experiment involved twenty autumn-born Holstein cattle (10 steers and 10 heifers), with


CH4 emissions measured using calorimeter chambers when animals were approximately 6, 12, 18, and 22 months of age. The cattle were offered a grass silage/concentrate based diet, typical of those used on commercial UK farms. Within each period gender had no effect (P > 0.05) on either nutrient digestibility or any CH4 emission variable (total CH4 emission, CH4 emission per kg live weight or feed intake, or CH4

energy output as a proportion of energy intake). Consequently the data from the two groups were pooled to develop prediction equations for daily CH4 emissions (g/d). A range of prediction equations were developed which indicated that CH4 emissions increased with increasing live weight, feed intake and energy intake (R2 values = 0.89 to 0.92). The data were also used to calculate accumulated CH4

emissions for the two genders. Although gender had no effect (P > 0.05) on the results, accumulated CH4

emissions increased with maturity (mean 36.2 and 64.3 kg/year for ‘years’ 1 and 2, respectively). Total CH4 emission factors (kg/year) during the first and second year of the rearing period were very strongly related to (R2= 0.75 to 0.95) to live weight recorded on a number of occasions during the rearing period. These data provide robust information on CH4 emissions from confined dairy heifers during the rearing period.

Task 5.3 – Methane emissions from dry, mature dairy cattle using respiration chambers:At Reading, a respiration chamber experiment evaluated effects of forage type (maize silage vs grass silage) and diet neutral detergent fibre (NDF) concentration (added chopped straw) using two 4 x 4 Latin squares with 4 barren dry cows and 4 lactating cows to determine the effects of physiological state (dry vs lactating) on CH4 emissions and response to diet composition. In a companion trial, the same diets were fed to 40 lactating dairy cows (10 cows per treatment) for 12 weeks to measure effects of treatments on feed intake and milk yield in a randomized block applied experiment. In addition to measurements of production response, CH4 emissions were estimated using an automated head chamber (GreenFeed, C-Lock, Rapid City, SD, USA) during the last 2 weeks of treatments. For chamber measurements, CH4 yield (g/kg DMI) was higher for dry compared to lactating cows, but the difference was not due to differences in total tract diet digestibility. Forage type and NDF concentration had no effect on CH4 production (g/d) or yield of dry cows. In lactating cows, CH4 yield was higher for grass compared to maize silage for both chamber and production studies, but the effect of NDF from straw on CH4 yield was not significant in the chamber study. In the production study, CH4 yield was increased by adding chopped straw for cows fed maize silage, but not grass silage. These observations suggest that effects of forage type and quality on CH4 production and yield may be attributable to effects on rate and extent of NDF digestion and rumen digesta kinetics.

WORKPACKAGE 6 - METHANE EMISSIONS FROM MANURE MANAGEMENTWorkpackage Leader: Tom Misselbrook, NW. Partners involved: NW, AFBI, Reading, SRUC, NottinghamMethane emissions from manure management are currently estimated in the UK GHG emissions inventory through a combination of Tier 1 and Tier 2 approaches (according to the IPCC 1996/2000 Guidelines). A Tier 2 approach (Equation 1) is used for the major livestock categories (cattle and pigs):

EFMS = VS 365 Bo 0.67 ΣMCF MS Eq. 1

where EFMS is the emission factor specific to a livestock type/manure management (kg CH4 head-1 yr-1), VS the volatile solids excreted by the livestock (kg head-1 y-1), Bo the maximum CH4 producing capacity of the manure (m3 kg-1 of VS), MCF the methane conversion factor (%) for a particular manure management and MS the proportion of manure managed within the specified manure management system.

The objectives of this workpackage were to assess whether the IPCC Guideline default values for these parameters are appropriate for use in the revised UK greenhouse gas inventory, or whether development of country-specific values is required.

Task 6.1 - Laboratory characterisation of livestock manuresSamples of excreta were collected from some of the cattle calorimeter chamber studies being conducted under WPs 4 and 5 of this project, which included growing dairy cattle, beef steers, beef suckler cows and dry dairy cows. The samples were analysed at North Wyke for total solids (TS) and VS content by oven drying and for Bo using a purpose designed laboratory system. Volatile solids content represented between 86 and 91% of the TS content of the cattle faeces. Total solids content was in the range 130 – 240 g kg-1 and there was evidence of a diet effect, with higher TS content faeces from cattle fed a concentrate as compared with forage diet. Daily VS output per animal increased with age for growing cattle, but estimates from this study were substantially below IPCC 2006 Guideline default values. Estimates of Bo from this study were broadly in agreement with IPCC 2006 Guideline default values. Further measurements from a wider range of cattle types and diets are required to develop robust country-specific values for these parameters.

Note: samples from the Reading University chamber experiment (dry dairy cows) have not yet been


analysed. These will be reported in a revised experimental report submitted as part of Defra project AC0114.

Task 6.2 - Assessing the ability of NIRS to predict methane emission potentialThis task was not carried out as problems with the NIRS instrument at North Wyke proved to be impossible to resolve. By agreement with Defra, the resource allocated to this Task was therefore diverted to Task 6.3 where measurements of ammonia, carbon dioxide and nitrous oxide were made in addition to the planned measurements of CH4 emission.

Task 6.3 - Methane emissions measurements from pilot-scale storesSix pilot-scale (1 m3) slurry storage experiments were conducted at North Wyke to quantify the CH4

conversion factor (MCF) values for cattle and pig slurries stored under controlled conditions, to assess the impact of temperature on MCF value and to assess two potential CH4 mitigation practices for slurry storage: a) adding a clay granule floating cover (assessed on pig slurry); and b) slurry acidification (assessed on cattle slurry). Slurries were stored for two months duration at one of three temperature regimes (summer, spring/autumn, winter). At the time of reporting, 4 experiments have been conducted; the remaining two will be reported in a revised experimental report submitted as part of Defra project AC0114. Cumulative CH4 emissions were greater from stored pig than cattle slurries; the MCF value derived for pig slurry storage was of a similar order to the IPPC default value, but that for cattle slurry was much lower. Storage duration and temperature are important factors influencing total CH4 emission and should be taken into account when developing country-specific MCF values. Covering pig slurry with a floating layer of clay granules was very effective at reducing ammonia emissions (by 70-80%) but had no impact on CH4 emissions. Acidification of cattle slurry was very effective at reducing CH4 (by about 90%) and ammonia (up to 100%) emissions, but maintaining pH to a value below 6.0 was important. Further measurements are required for the development of robust country-specific MCF values.

Data from the pilot-scale farm-yard manure (FYM) storage experiment conducted as part of Defra project AC0112 were also used in this study. Mean Bo for the cattle FYM was 0.18 m3 CH4 kg-1 VS, exactly the same as the IPCC 2006 Guideline default value for ‘Other cattle’ excreta. No measurement of Bo for the pig FYM was available, so the default IPCC 2006 Guideline value of 0.45 m3 CH4 kg-1 VS was assumed. Based on these and the measured VS contents of the FYM, MCF values of 0.8 – 2.0% and 3.6% for pig and cattle FYM, respectively, were derived. These are in close agreement with the IPCC 2006 Guideline default value for ‘solid storage’ under cool conditions (annual average temperature of <10 to 14 °C) of 2.0%.

Task 6.4 - Developing manure management methane EF for livestock systemsExperimental work under this work package has raised some important points for consideration in the development of an improved estimation of CH4 emissions from manure management in the UK greenhouse gas inventory model. It is recommended that the IPCC Tier 2 approach is used for the major livestock categories, but that some UK-specific parameterisation is warranted based on the experimental evidence to date.

Referring to Equation 1:

VS excreted – there is evidence VS output in excreta from UK cattle is substantially lower than the default values given by IPCC 2006 Guidelines. However, our values are based on a very limited data set and the development of robust country-specific values to replace the IPCC defaults requires a more comprehensive dataset representing a range of cattle types and diets. Across the cattle excreta analysed in this study, VS was consistently about 90% of TS content. If previous cattle calorimeter chamber experiments have measured daily faecal TS output, then a good approximation of daily VS output could be derived. It is recommended that a data search is conducted of previous UK experiments (most likely relating to AFBI and Reading University trials) to put towards a more comprehensive data set.

Bo value – the evidence from this study is that the default IPCC 2006 Guideline values for Bo for other cattle and market pigs are appropriate for use in the UK estimation. However, further experimental evidence across a wider range of livestock and manure types would be useful to confirm this.

MCF values – based on a limited experimental data set, the evidence from this study is that the default IPCC 2006 Guideline MCF values for pig slurry storage and cattle and pig FYM storage are appropriate. For cattle slurry, MCF values derived from our experiments were substantially lower than the IPCC default. It is recommended that the MCF values used for slurry storage should take into account storage duration and time of year (temperature), but further studies are required to provide sufficient parameterisation for this.WORKPACKAGE 7 – MODELLING METHANE EMISSIONSWorkpackage Leader: Les Crompton, Reading. Partners involved: Reading, AFBI, IBERS, SRUC,


Nottingham, NWThis WP utilised CH4 emission data measured from livestock and their manures to generate EFs and to develop EF proxies from archived animal characterisation data. The results of this WP will be fed through AC0114 to SCF0102 for use in inventory reporting purposes. The aim was to provide comprehensive EFs for CH4 excretion that should be capable of broad practical application across a range of typical UK feeding regimes and livestock systems. In addition to this, models were generated in relation to proxies derived from existing datasets of animal data that do not include CH4 emission measurements.

Within the project consortium, two major existing datasets of energy balance data, including measurements of CH4 emission across a broad range of diet types, animal characteristics and treatments, were amalgamated and expanded. More recent data from University of Reading and AFBI, together with existing data from the USA, the Netherlands, and Rothamsted Research were included to create a single dedicated Access database containing 2682 individual measurements of CH4 emission from lactating and non-lactating cattle. We were unable to secure archived sheep data from ADAS, Drayton. The final archive data set covered a broad range of animal characteristics (dairy cows - lactating/dry, breed/genetic merit, parity/stage of lactation; beef cattle - growing/lactating; sheep – mature) and dietary description (TMR/grass silage/fresh grass; forage type and proportion; quality; additives). The extent to which the diet had been characterised varied widely between the different data sets, from book values to individual measurements. Supplemental data describing the experiments also varied from extensive to limited. A multivariate analysis was conducted with appropriate adjustments for variance associated with location and trial effects, to determine the most important dietary factors that influence CH4 emission and the most appropriate proxy indicator that could be used to predict CH4 emission on farm.

The results emphasised that, as highlighted in many previous meta-analyses and reviews of published data, total feed dry matter intake had an overriding effect on the amount of CH4 produced by lactating and non-lactating cattle across a broad range of diet types and productive states. In contrast to the clear effect of the level of intake, most measures of dietary nutrient composition were found to be non-significant factors in determining CH4 emissions across the dataset. Including a measure of diet quality through the use of NDF in the models did lead to a small improvement in prediction in most cases. However, the error associated with estimating the level of NDF in any given diet in the absence of direct measurement are likely to outweigh any improvements to the model. The current IPCC Tier 2 method of estimating CH4

emissions assumes a constant 6.5% of gross energy intake being lost as CH4. For lactating cattle in this analysis, this represents the observed CH4 output from an animal eating 13 kg dry matter per day. However, a lactating animal eating 20 kg dry matter per day (typical intake in mid-lactation in UK) would emit only 5.7% of the gross energy intake as CH4. The proportion of gross energy intake lost as CH4

declines as the level of intake rises at a rate of 0.12% per kg dry matter intake. For non-lactating cattle, in this analysis, the rate of decline was steeper (0.23%/kg DMI) and a loss of CH4 at 6.5% of gross energy intake represents an animal eating just over 9 kg of dry matter a day.

When reliable estimates of intake are unavailable, an alternative relationship between feed intake and CH4

production is required. For lactating cattle, metabolisable energy requirement is linearly correlated to CH4

output and although the model demonstrates a higher level of prediction error than those relating intake to CH4 output, metabolisable energy requirement was the most appropriate proxy model for predicting CH4

emissions from lactating cattle. The ability to estimate the metabolisable energy requirement of lactating animals in different scenarios means that models of CH4 output based on metabolisable energy requirement were the most practical solution. For non-lactating cattle, we were unable to derive a similar relationship between metabolisable energy requirement and CH4 emissions or another proxy parameter due to reduced availability of data for model development compared with the lactating cattle. Therefore, for non-lactating cattle we recommend staying with the current IPCC Tier 2 method.

As part of the analysis of the CH4 database, we examined the data for evidence of known dietary factors that can influence CH4 emissions from cattle and which could potentially be used as mitigation strategies within the UK. The two factors chosen were dietary fat content and dietary forage proportion and composition. Whilst previous research has demonstrated the effect of added dietary fat on CH4 emissions within carefully controlled experimental conditions, there was no evidence of a relationship between dietary ether extract and CH4 production or CH4 as a proportion of gross energy intake. Within the database it was not possible to distinguish between fat concentration of the basal diet and supplementary additives or between the different types of fat. For this reason it was not possible to incorporate such effects in a model suitable for integration in an inventory scheme. The balance of starch and fibre in the diet could not be shown to exert a clear effect on the CH4 output. As with dietary fat, this does not mean that no effect exists, merely that within the context of the available data the determination of the nature of the effect is not possible. The variation in CH4 yield per unit of dry matter intake for any given level of consumption was too great to allow the development of a suitable model describing the influence of this factor. The large variation in the data prevented the construction of any reliable model describing the effect of either of these potential mitigation measures. A detailed report on emission factor synthesis and emission proxy modelling using the archived data set is presented in Appendix C.


Having completed the analysis of the archived CH4 data and prior to AC0115 data being made available, there was an opportunity to assemble a data archive of nitrogen balance observations and conduct a similar modelling analysis as for CH4. A database of nitrogen balance observations from lactating and non-lactating cattle include data from University of Reading, AFBI, IBERS, and organisations in the USA and the Netherlands, giving a total of 2032 individual observations. A multivariate analysis was conducted, with appropriate adjustments for variance associated with location and trial effects, to determine the most important dietary factors that influence nitrogen excretion and the most appropriate proxy indicator that could be used to predict nitrogen excretion on farm. The results emphasised that nitrogen intake is the principal driver of nitrogen excretion either in urine, faeces or manure by cattle across a broad range of diet types and productive states. As nitrogen intake increases above requirement, the excess nitrogen is partitioned largely towards urinary nitrogen with relatively modest increases in faecal and milk nitrogen. In contrast to the clear effect of nitrogen intake, most measures of dietary nutrient composition were found to be non-significant factors in determining nitrogen excretion across the data set. In the absence of nitrogen intake data, metabolisable energy requirement was considered the practical proxy solution on-farm, for predicting nitrogen excretion from lactating cattle, being linearly correlated to manure nitrogen excretion. For non-lactating cattle, the lack of reliable proxies for nitrogen intake in the absence of direct observations meant that the current analysis was unable to improve on the existing recommendations from Cottrill & Smith (2010).

Data from the experimental studies undertaken during this project have been assimilated into the database of CH4 observations. These studies have thus far produced 2112 individual observations of enteric CH4 production from sheep and cattle. Some observations were excluded from use in the final synthesis due to equivocal associations between CH4 production and dry matter intake. These include 392 observations from cattle obtained using the on-farm sniffers and the GreenFeed head chamber and 61 observations from lactating sheep where adult animals were measured with variable numbers of lambs. The usable new data intended for EF synthesis includes growing and mature sheep (n = 474) with eight breeds and five primary forages and cattle data (n = 1185) predominantly from growing animals with some additional data for lactating and dry dairy, covering eight breeds and nine primary forages.

Initial analysis of the AC0115 data confirms that as for the archived data set, the primary driver of CH4

emission appears to be dry matter intake. The effect of dietary components is relatively minor compared to the dominant effect of total feed dry matter intake. Animal genotype, nutrition, forage type, bodyweight and gender do not appear to have a significant influence on CH4 production in either sheep or cattle. Physiological state may have a significant effect on CH4 yield and CH4 emission expressed as a percentage of gross energy intake. AC0115 data similarly confirmed the tendency observed with the archive data for the proportion of gross energy intake lost as CH4 to decline as the level of intake rises. The decline with increasing intake was more pronounced for sheep (2.67%/kg DMI) compared to cattle (0.19%/kg DMI) and contrasts with the current IPCC method, whereby a fixed percentage of gross energy intake is assumed to be emitted as CH4. The results of an initial analysis of the AC0115 data set is presented in Appendix D.

Enteric CH4 emission factors and emission factor proxies generated during this project will be reviewed and revised using the experimental data generated in AC0115 as part of the final synthesis in project AC0114. This task will involve close collaboration with colleagues to identify the appropriate characterisation of livestock systems and systems based emission factors to include in the revised inventory structure. The data set used for the final emission factor synthesis will contain approximately 4400 individual observations of CH4 emission from cattle and sheep.

WORKPACKAGE 8 – KNOWLEDGE EXCHANGEWorkpackage Leader: Jon Moorby, IBERS. Partners involved: AllThe purpose of this WP was to foster effective knowledge exchange between project partners and between this project and other related projects (AC0112/SCF0102, AC0114 and AC0116), and to ensure that knowledge generated by this project was disseminated using appropriate outlets (peer-reviewed publications, scientific meetings, stakeholder interactions).

Task 8.1 – Internal knowledge exchangeThe AC0115 Project Management Team comprised WP leaders, partner organisation representatives, the AC0112, AC0114 and AC0116 Project Leaders, and an independent consultant statistician. Face-to-face meetings of the AC0115 Project Management Team were held every 6 months, with each meeting hosted by a different partner organisation. Teleconference meetings took place regularly between these face-to-face meetings. Knowledge exchange on particular technical issues were addressed at specific events attended by both scientists and technical support staff, such as the workshops to disseminate best practice on the use of the SF6 technique (organised by AFBI, February 2011) and to review options and best practice for estimating feed intake and grazing behaviour in free-ranging animals (organised by


SRUC, June 2011). Both were well attended, with 27 delegates attending the SF6 workshop, and 14 delegates at the grazing intake workshop. A follow up technical workshop to discuss issues arising during the first year of experimental work was held in Edinburgh in January 2012 and was attended by 22 delegates.

Ad hoc teleconferences and meetings to enable knowledge exchange between AC0115 and the other GHG Platform projects were held as required to address particular topics; such as, to determine how best to collect and present data to allow uncertainty analyses to take place in project AC0114, and how to present data for archiving for future use. Members of the AC0115 consortium also participated in stakeholder workshops organised by AC0114, and have contributed towards the Platform Project web-site (http://www.ghgplatform.org.uk/).

Task 8.2 – External knowledge exchangeThe project had a Project Advisory Group (PAG) comprised of representatives from Defra and the devolved authorities, and representatives from the livestock industry in the form of the levy bodies (DairyCo, EBLEX, HCC, QMS, LMC, and AgriSearch). The PAG was chaired independently by Dr David Garwes. Meetings at which the Project Management Team presented updates on progress were held every 6 months. The PAG also received copies of protocol synopses as experimental work was being developed in order to provide feedback to the researchers in terms of industry relevance. Monthly activity reports were compiled from AC0115 consortium partners, and these are supplied to the GHG Platform secretariat for compilation into GHG Platform activity reports for wider dissemination. Knowledge exchange between GHG platform projects and with a wider audience (Defra, representatives of the devolved authorities and other stakeholders) was further facilitated by annual Cross-Platform Meetings. Results from the project have featured at a range of national and international scientific conferences, including the Greenhouse Gases in Animal Agriculture conference held in Dublin in June 2013. In addition, all partners hosted significant numbers of academic, policy, and industry visitors from both home and abroad throughout the course of the project. AC0115 project members have also been involved in a number of Global Research Alliance (GRA) activities.

DISCUSSIONThis project was run in close liaison with project AC0114, part of which aims to develop new EFs by exploiting existing datasets held by partner organisations. Those datasets consist of measurements of CH4 emissions from ruminant animals fed well-characterised diets. In this project, those datasets were augmented by new measurements of systems, or components of systems, either absent or under-represented in the existing datasets, to deliver baseline values for CH4 emissions and estimates of currently unknown effects of animal breeds and genotypes, age, diet, seasonality and regional variation. Analysis of historic and new data reinforce previous findings that feed DM intake is a major driver of CH 4

production, with relatively minor effects of diet and breed being found. However, there is a large amount of variation in CH4 production for a given level of feed intake, which can be exploited both through future breeding programmes (of animals and plants) and improved nutritional activities. This requires further research to determine the most appropriate courses of action to be taken and the most appropriate animals are used to maximise production efficiency.

Approximately 90% of dairy cattle registered in 2008 were black and white breeds (over 2,900k, compared with approximately 250k cattle of other dairy breeds; The Cattle Book 2008). This emphasises the relative importance of black and white cattle for milk production, most of which occurs in the lowland regions of the UK. A large amount of data on CH4 emissions from dairy cows was available from archived sources from both the UK and overseas at the start of the project for initial investigations of relationships between diet and CH4 output. To augment this and fill in areas that have received relatively little attention in the past the dairy cow studies in this project focussed on growing young stock, dry cows, and in particular to all categories of dairy cattle at grazing. Unlike the predominance of black and white dairy cattle, regional variation has led to the UK having a much more diverse and dynamic breeding herd/flock pattern within its beef and sheep systems. These encompass not only large numbers of different breeds, but, uniquely, the use of crossbreeds as an important linkage between systems of production, e.g. from dairy to beef, and from hills to lowlands. With this in mind the project consortium focussed on breeds and systems that in part represent the regional patterns, but together provide a framework that covers the important elements of system and breed, and genotype. For example, Limousin, and in particular Limousin crossbreds, are the most common beef cattle in Britain according to BCMS data, with Aberdeen Angus fourth, and the Limousin cross is accepted to be the most common suckler cow genotype in the UK. Hardy hill breeds describe another important and somewhat different classification of cow and system, and there is good evidence that grazed intake differs between breeds developed for extensive or intensive systems. Furthermore they represent regional issues through regional variation in cattle breed choice. Similarly, sheep breed types range from specialist hill breeds, with the Scottish Blackface most important in both Scotland and Ireland, and the Welsh Mountain in Wales, through a range of crossbreds bred from the


Blackface and similar hill ewes that represent the core of upland systems across the whole UK. These, together with newer closed purebred upland flocks span the continuum from hill to lowland, before fitting into a fuller lowland sheep system relevant for all systems covering the UK. Thus, the approach adopted for the sheep and beef cattle elements of the project were similar, and encompassed both traditional and emerging management systems and breed choices. Despite this many options remain untested, and further work is required to ensure the general conclusions drawn from this work are appropriate for the full range of breeds, diets, and production systems that are used in UK livestock agriculture. Similarly, although some data was generated by this project on methane production from cattle and pig manures, further measurements of daily VS output are required for a range of cattle types and diets to develop robust country-specific values for use in the improved UK greenhouse gas inventory model. Further B o

measurements are also required from a wider range of animals and manure types to determine whether IPCC 2006 Guidelines default values are applicable for the UK model.

A number of novel methods for measuring methane emissions from livestock on-farm were used and assessed as part of this project. Such methods would be useful for verification of inventory calculations, and for use by farmers to monitor their own animals and any practical measures they implement to reduce GHG emissions from their farms. None of the on-line methods of measuring methane emissions used in the project appear to be precise enough to enable the derivation of EFs for inventory reporting, although they show promise for possible verification purposes. Future development of these methods may increase accuracy and precision.

CONCLUSIONSNumerous conclusions can be drawn from the large amount of work that has been carried out during the course of this project, and these are highlighted in the experimental summaries in Appendix A.

In terms of measurement techniques (WP2) the two main methods used in the project were chambers and the SF6 dilution technique. Calibration of the chambers at the partner sites by NPL highlighted the importance particularly of outlet airflow – this contributed much of the variation found. The use of calibration factors to correct for individual chamber variation means that the absolute values measured in the project are as precise as possible for developing UK-specific EFs. It is not possible to measure CH4

emissions from grazing animals using chambers, and therefore the SF6 technique was adopted with the assistance of AFBI’s experience. Work at AFBI showed that methane measurements by SF 6 correlate well with chamber measurements, at least within the chamber environment. However, SRUC demonstrated that animal behaviour, in both sheep and cattle, was affected by the presence of the SF 6

breath collection equipment, although it was not possible to determine how this affected the measurements made. A number of practical on-farm measurement techniques were investigated, including the use of online meters (sniffers) in milking machines and feed bins, and the commercially available GreenFeed machine. A factor associated with the efficacy of all of these techniques is the frequency of use; beef cattle fed indoors in feed bins, and dairy cows that are milked twice daily (or more frequently using robotic equipment) are more likely to yield more precise measurements than animals grazing outside and are less interested in visiting a GreenFeed machine than they are when indoors.

In sheep, a lot of work investigated the effect of breed and breed type on daily enteric CH4 emissions and CH4 yield from feeds. In general, there was little effect of breed type (which includes size, or body weight) on CH4 outputs that was not related to feed intake. Smaller animals tended to eat less than larger animals, and therefore produced less CH4 per day, but produced the same amount per unit of feed intake. However, body weight was not a good proxy of intake – there was a positive, but relatively poor, relationship between body weight and daily CH4 emissions. However, within-genotype differences between improved and unimproved breeding lines of Scottish Blackface sheep were found; high genetic merit animals produced more CH4 (per day and per unit intake) than lower genetic merit animals. Diet tended to have a much greater effect on CH4 emissions, and Ym was affected by diet. On relatively good quality diets, such as improved ryegrass swards, Ym was found to be close to the IPCC default value of 6.5%. On poorer quality diets, such as permanent pasture and upland rough grazing, Ym was lower.

In beef cattle, as with sheep, there was limited effect of breed and breed type on enteric CH4 emissions (daily emissions and CH4 yield from feeds). There was a much greater effect of diet type, with animals consuming more higher-quality (lowland) forage than poorer-quality (upland) forages and consequently producing more CH4 each day on the better quality feeds. Similarly, animals fed concentrate-based diets, compared with those fed high-forage diets, produced less CH4 per day and per unit feed intake, with less effect of cattle breed. Most of the breed effects seen, including effects of beef animal sire, were due to differences in feed intake, sometimes driven by genetic potential for growth.

Much previous work has been carried out on enteric CH4 emissions from dairy cows, but little has been done with them at grazing, while dry, or with dairy youngstock. In youngstock, there was no effect of


gender on CH4 emissions, but emissions increased with increasing age as the animals consumed more feed. Increasing the proportion of concentrate in lactating dairy cow diets significantly increased feed intake but had no effect on daily CH4 emissions, so that methane yield was reduced and Ym was reduced. No significant effect of feeding a supplemental fat source was found on CH4 emissions from growing heifers, whereas there were significant reductions in CH4 emissions from heifers fed forages based on wild-flower swards, compared to swards of ryegrass, ryegrass/clover and birdsfoot trefoil. Methane yields from feeds were higher from dry cows than from lactating cows, which may be related to the rate of passage of feed through the rumen – a slower passage rate in dry cows may allow the rumen population more chance to ferment the feed and therefore produce more CH4 per unit of feed intake than in lactating cows. Work that investigated the effect of dairy cow breed on CH4 emissions found little effect of breed, as was found for beef cattle and sheep. It is concluded that between-animal variation is greater than between-breed variation.

Preliminary synthesis of the new data collected as part of this project reinforces the message that feed intake is the major driver of CH4 production in both cattle and sheep. There are no major effects of gender or breed, and while significant effects of diet can be found within controlled experiments, the effects are less clear across experiments. Physiological state (e.g. dry versus lactating cows) may be important because of changes in digesta passage rates, and this may also contribute to the negative relationship between Ym and feed intake. Current on-farm technologies for assessing methane production that were used by the project do not appear to be reliable for generating emission factors, because CH4 production data collected by these methods were not significantly related to feed intake.

Although the majority of CH4 emissions from ruminant livestock emanate from the gut, a significant proportion can be released from manures, and a major proportion comes from the manures of monogastric animals. Laboratory characterisation of manures collected as part of some of the cattle measurements in this project indicated that the volatile solids components were substantially lower than the default IPCC guidelines values, although the methane production potential (B0) values were similar. In a comparison between pig and cattle slurry in pilot-scale slurry stores, emissions of CH4 and ammonia were higher for pig slurry than for cattle slurry. Acidification of cattle slurry was effective at reducing emissions of both CH4 and ammonia, while the use of floating clay granules reduced ammonia but not CH 4

emissions.

ADDED VALUEA number of projects and activities were associated with the work going on in the project at the various consortium partner organisations. These include postgraduate student activities, exchanges with visiting research workers, links to work being carried out as part of other research projects funded by other funding agencies, and interactions with the Global Research Alliance. These added value activities are listed in Appendix E.


References to published material9. This section should be used to record links (hypertext links where possible) or references to other

published material generated by, or relating to this project.REFEREED PAPERS TO DATEPublished/submittedBell, M.J., Potterton, S.L., Craigon, J., Saunders, N., Wilcox, R., Hunter, M., Goodman J.R and Garnsworthy P.C. Variation in enteric methane emissions among cows on commercial dairy farms, Journal of Dairy Science (submitted).

Bell, M.J., Saunders, N., Wilcox, R., Homer, E.M., Goodman, J.R., Craigon J. and Garnsworthy, P.C. Methane emissions among individual dairy cows during milking quantified by eructation peaks or ratio with carbon dioxide Animal (submitted).

Hammond KJ, Humphries DJ, Westbury DB, Thompson A, Crompton LA, Kirton P, Green C, Reynolds CK. The inclusion of diverse forage species in the diet of growing dairy heifers: impacts on animal productivity and methane emissions. Agriculture, Ecology and Environment (submitted).

Jiao, H.P., T. Yan, D.A. Wills, A.F. Carson and D.A. McDowell. 2013. Development of prediction models for quantification of total methane emission from enteric fermentation of young Holstein cattle at various ages. Agriculture, Ecosystems & Environment, 183: 160–166.

Jiao, H.P., T. Yan, D.A. Wills, A.F. Carson and D.A. McDowell. 2013. Development of the maintenance energy requirement for young Holstein cattle from calorimeter data measured at 6, 12, 18 and 22 months of age. Animal (submitted).

Jiao, H.P., T. Yan, D. A. McDowell, A. F. Carson, C. P. Ferris and D. L. Easson. 2013. Enteric methane emissions and efficiency of utilization of energy in Holstein heifers and steers at age of six months. Journal of Animal Science 91:356-362.

Jiao, H.P., T. Yan, D. A. McDowell. 2014. Prediction of manure nitrogen and organic matter excretion for young Holstein cattle fed on grass silage-based diets. Journal of Animal Science (in press).

Jiao H. P., A. J. Dale, A. F. Carson, S. Murray, A. W. Gordon and C. P. Ferris. Effect of concentrate supplementation level on enteric methane emissions from grazing dairy cows. Journal of Dairy Science (submitted).

McBride, J., Morrison, S. J., Yan, T. and Gordon, A.. Methane emissions from grazing dairy herd replacements estimated using the sulphur hexafluoride technique. Journal of Animal Science (submitted).

Richmond, A.S., A.R.G. Wylie, A.S. Laidlaw and F.O. Lively. 2014. An investigation of methane emissions from beef cattle grazing on semi-natural upland and improved lowland pastures. Animal (submitted).

Ricci, P., Rooke, J. A., Nevison, I., Waterhouse, A., Nov. 2013. Methane emissions from beef and dairy cattle: Quantifying the effect of physiological stage and diet characteristics. Journal of Animal Science 91 (11), 5379–5389. URL http://dx.doi.org/10.2527/jas.2013-6544

Zou, C. X., F. J. Lively, A. R. G. Wylie, and T. Yan. 2013. Estimation of the maintenance energy requirements, methane emissions and nitrogen utilisation efficiency of two suckler cow genotypes. Animal (submitted).

In preparationFerris, C.P., Jiao, H.P. and Gordon, A.W. Enteric methane emissions from non-lactating pregnant dairy cows while grazing. Paper in preparation.

Ferris, C.P., Jiao H. P., A. W. Gordon, S. Murray and A. F. Carson. Effect of cow genotype and concentrate feed level on milk production and enteric methane emissions from grazing dairy cows. Paper in preparation.

Fraser, M.D., Fleming, H., Moorby, J.M. Traditional vs modern: role of breed type in determining enteric methane emissions from cattle grazing as part of contrasting grassland-based systems. For submission to Journal of Animal Science.

Gardiner, T.D., M.D. Coleman, F. Innocenti, J. Tompkins, A. Connor, P.C. Garnsworthy, J. M. Moorby, C.K. Reynolds, A. Waterhouse, D. Wills. Determination of the Absolute Accuracy of UK Chamber Facilities used in Measuring Methane Emissions from Livestock. For submission to Global Change Biology.


Hammond KJ, Humphries DJ, Crompton LA, Kirton P, Green C, Reynolds CK. Methane emissions from dairy cattle estimated using an automated head chamber (GreenFeed). For submission to Journal of Animal Science.

Hammond KJ, Humphries DJ, Crompton LA, Kirton P, Green C, Reynolds CK. Effects of forage source and supplemental dietary fat on methane emissions from growing dairy heifers of differing body weights. For submission to Animal.

Zhao, Y.G., R. Annett, T. Yan and N.E. O’Connell. 2014. Effects of forage and breed types on methane emission and the efficiency of utilisation of energy and nitrogen in hill replacement ewes. For submission to Animal.

CONFERENCE PROCEEDINGSAubry, A., R Annett, T Yan. 2014. Effects of breed and forage types on methane emission factors for lowland replacement ewes aged between 8 and 19 months. Proceedings of the British Society of Animal Science, p 25.

Aubry, A., R Annett, T Yan and A Uprichard. 2014. Effects of breed and forage types on methane emission factors for hill replacement ewes aged between 9 and 18 months. Proceedings of the British Society of Animal Science, p 29.

Bell, M.J., Potterton, S.L., Caigon, J., Saunders, N., Wilcox, R., Hunter, M. Goodman, J.R. and Garnsworthy, P.C. 2013. Variation in enteric methane emissions among cows on commercial dairy farms; Advances in Animal Biosciences, Volume 4 Part 3, 438.

Chagunda, M. 2013. Opportunities and challenges in the use of the Laser Methane Detector to monitor enteric methane emissions from ruminants; Animal, Volume 7 supplement 2.

Dong, L., T Yan, C P Ferris and D A McDowell. 2004. A comparison of enteric methane emissions by Holstein-Friesian dairy cows and crossbred/Norwegian dairy cows. Proceedings of the British Society of Animal Science, p 97.

Doran, S.E., Leemans, D.K., Vale, J.E., Corton, J., Fraser, M.D., and Moorby, J.M. 2013. In vitro gas production as a means to measure methane produced by a variety of upland plants when incubated with rumen fluid. Advances in Animal Biosciences: Proceedings of the 5th Greenhouse Gases and Animal Agriculture Conference (GGAA 2013), Dublin, Ireland. Vol. 4 (2) Cambridge University Press, 2013. p. 459.

Doran, S.E., Leemans, D.K. and Moorby, J.M. 2013. In vitro gas production to test methane production from mixtures of two contrasting upland plant samples in varying proportions. Advances in Animal Agriculture: Proceedings of the 5th Greenhouse Gases and Animal Agriculture Conference (GGAA 2013), Dublin, Ireland. Vol. 4 (2) Cambridge University Press, 2013.

Duthie, C-A., Rooke, J.A., Hyslop, J.J., Ross, D.W. and Waterhouse A 2013 Methane emissions of two divergent breeds of beef suckler cows offered a straw based diet with either grass silage or brewers grains. In ‘Greenhouse Gases In Agriculture’, International conference held at University College Dublin, June, 2013.

Duthie, C-A., Rooke, J.A., Hyslop, J.J., Ross, D.W. and Waterhouse A 2013 Methane emissions of two divergent breeds of beef suckler cows offered a straw based diet with either grass silage or brewers grains. In ‘Greenhouse Gases In Agriculture’, In ‘Sustainable Intensification – the pathway to low Carbon farming’ proceeding of conference, Edinburgh, Sept 2013.

Ferris, C.P., Aubry, A., Vance, E.R., Yan, T. and Morrison, S.J. 2013. Greenhouse gas emissions from a grazing system and a confinement system involving different dairy cow genotypes. In: Proceeding of the British Grassland Society 11th Research Conference: Science and Practice for Grass-Based Systems. Paper 1.5., Dumfries, Scotland.

Ferris, C.P., Jiao, H.P. and Gordon, A.W. 2014. Enteric methane emissions from non-lactating pregnant dairy cows while grazing. Proceedings of The British Society of Animal Science Annual Meeting, Nottingham, April 2014.

Fraser, M.D., Fleming, H.R., Davies, J.W. and Moorby, J.M. 2013. Effect of breed and pasture type on methane emissions by growing beef steers. Advances in Animal Biosciences: Proceedings of the 5th Greenhouse Gases and Animal Agriculture Conference (GGAA 2013), Dublin, Ireland. Cambridge University Press, Vol. 4 (2), p. 359.

Fraser, M.D., Fleming, H.R., Theobald, V., Sanderson, R. and Moorby, J.M. 2013. Effect of body size on feed intake and methane emissions from ewes offered fresh forage. Advances in Animal Agriculture:


Proceedings of the 5th Greenhouse Gases and Animal Agriculture Conference (GGAA 2013), Dublin, Ireland. Vol. 4 (2) Cambridge University Press, 2013.

Fraser, M.D., Fleming, H.R., Theobald, V.J. and Moorby, J.M. 2014. Effect of breed type and pasture type on methane emissions from weaned lambs offered fresh grasses. Proceedings of the Joint Annual Meeting of ASAS, ADSA and CSAS, Kansas City, July 2014.

Gardiner T.D. and Coleman M.D., (2013) Metrological assessment of the absolute accuracy of methane emission measurements from livestock chambers in the UK; Advances in Animal Biosciences, Volume 4 Part 3, 480

Hammond, K.J., Humphries, D.J., Crompton, L.A., Kirton, P., Green, C. and Reynolds C.K. (2013) Methane emissions from growing dairy heifers estimated using an automated head chamber (GreenFeed) compared to respiration chambers or SF6 techniques. Advances in Animal Biosciences, Volume 4 Part 3, 391

Hammond KJ, Humphries DJ, Crompton LA, Kirton P, Green C, Reynolds CK 2013. Effects of forage source and supplemental dietary fat on methane emissions from growing dairy heifers of differing body weights. Proceeding of the 5th Greenhouse Gases and Animal Agriculture Conference. Advances in Animal Biosciences, 4, pp 364.

Hammond KJ, Reynolds CK, Humphries DJ, Crompton LA, Kirton P, Green C 2013. The influence of forage mixtures on methane emissions from growing dairy cattle. Proceedings of the British Society of Animal Science, 4, pp 29.

Hammond KJ, Jones AK, Humphries DJ, Crompton LA, Reynolds CK 2014. Effects of forage source and neutral detergent fiber concentration on methane emissions and milk production of dairy cows. Submitted to the 2014 Joint Annual Meeting of the American Dairy Science Association, American Society of Animal Science, and the Canadian Society of Animal Science, Kansas City, USA.

Hammond KJ, Jones AK, Humphries DJ, Crompton LA, Reynolds CK 2014. Methane emissions from lactating and non-lactating dairy cows fed diets differing in forage source and neutral detergent fiber concentration. Submitted to the 2014 Joint Annual Meeting of the American Dairy Science Association, American Society of Animal Science, and the Canadian Society of Animal Science, Kansas City, USA.

Humphries D, Hammond KJ, Westbury D, Crompton LA, Green C, Reynolds CK 2013. Effect of three pasture forage mixtures on methane emissions by dairy heifers. Proceedings of the British Grassland Society and British Society of Animal Science Joint Meeting, 75.

Jiao, H.P., T Yan, S.J. Morrison, A.F. Carson and D.A. McDowell. 2013. Quantification of enteric methane emissions from young Holstein heifers and steers fed grass silage diets. In: The proceedings of the 5th Greenhouse Gases and Animal Agriculture, p356, Dublin, Ireland.

Jiao, H.P., T Yan, D.A. McDowell and A.F. Carson. 2013. Development of maintenance energy requirement for young Holstein cattle using calorimeter data measured at age of 6, 12, 18 and 22 months. In: The proceedings of the Annual Meeting of British Society of Animal Science, p66, Nottingham, UK.

Jiao, H.P., T Yan, D.A. McDowell and A.F. Carson. 2013. Evaluation of the efficiency of nitrogen utilisation of young Holstein cattle at age of 6 to 22 months. In: The proceedings of the Annual Meeting of British Society of Animal Science, p57, Nottingham, UK.

Jiao, H., T Yan, D.A. McDowell, A.F. Carson, C.P. Ferris and D. L. Easson. 2012. Measurements of enteric methane emissions from Holstein heifers and steers at age of six months. In: The proceedings of the Annual Meeting of British Society of Animal Science, p140, Nottingham, UK.

Jiao, H., T Yan, D.A. McDowell, A.F. Carson, C.P. Ferris and D. L. Easson. 2012. Evaluation of the efficiency of utilisation of nitrogen for Holstein heifers and steers at age of six months. In: The proceedings of the Annual Meeting of British Society of Animal Science, p139, Nottingham, UK.

Jiao H. P., A. J. Dale, A. F. Carson, S. Murray, A. W. Gordon and C. P. Ferris. 2014. Effect of concentrate supplementation level on enteric methane emissions from grazing dairy cows. Proceedings of The British Society of Animal Science Annual Meeting, Nottingham, April 2014.

Jiao H. P., A. W. Gordon, S. Murray, A. F. Carson and C. P. Ferris. 2014. Effect of cow genotype and concentrate feed level on milk production and enteric methane emissions from grazing dairy cows. Proceedings of The British Society of Animal Science Annual Meeting, Nottingham, April 2014.

McBride, J., Morrison, S.J. Gordon, A. 2013. Methane emissions from grazing dairy herd replacements estimated using the sulphur hexafluoride technique. British Society of Animal Science and Agricultural Research forum, Nottingham, April 2013.

McBride, J., S. J. Morrison and T. Yan. 2013. Review of enteric methane emissions of cattle and sheep fed diets relevant to UK farming conditions. In: The proceedings of the 5th Greenhouse Gases and Animal


Agriculture, p299, Dublin, Ireland.

McBride, J., Morrison, S.J. Yan, T and Gordon, A. W. 2014. Relationship between enteric methane emissions, gross energy intake and liveweight of Holstein Friesian growing heifers. Proceedings of the British Society of Animal Science, p 219.

McBride, J., S J Morrison, T Yan, A W Gordon. 2014. A review of the impact of increased dietary starch concentration or addition of oils, fats, tannins or saponins in the diet on enteric methane emissions. Proceedings of the British Society of Animal Science, p 81.

McBride, J., Morrison, S.J. and Gordon, A. W. 2014. Investigating the SF6 technique methodology- measuring flow rate over time. Agricultural Research Forum, Tullamore, March 2014.

McBride, J., Morrison, S.J. and Gordon, A. W. 2014. Investigating the SF6 technique methodology- Impact of connecting and disconnection a sampling line on canister pressure. Agricultural Research Forum, Tullamore, March 2014.

Nevison, I., Ricci, P., Rooke, J., Waterhouse, A. 2013. Predicting methane emissions from cattle – Where meta-analysis and random coefficient modelling meet. Presented at the International Biometric Society 4th Channel Network Conference, July, 2013, St Andrews, Scotland, UK.

Pavlu, V., Fraser, M.D., Fleming, H.R., Moorby, J.M. and Collins, R.P. 2013. Effect of sward species mix on methane emissions from ewes. Advances in Animal Biosciences: Proceedings of the 5th Greenhouse Gases and Animal Agriculture Conference (GGAA 2013), Dublin, Ireland. Cambridge University Press, Vol. 4 (2), p. 361.

Ricci, P., Houdijk, J., Duthie, C-A., Roehe, R., Hyslop, J. and Waterhouse, A. (2013) Methane from ewes and steers measured with the Laser Methane Detector correlates with open-circuit respiration chambers measurements. Advances in Animal Biosciences, Volume 4 Part 3, 548.

Ricci, P., Houdijk, J., Duthie, C-A., Roehe, R., Hyslop, J.J. and Waterhouse, A. (2013) Methane from ewes and steers measured with the Laser Methane Detector correlates with open-circuit respiration chambers measurements In ‘Sustainable Intensification – the pathway to low Carbon farming’ proceeding of conference, Edinburgh, Sept 2013.

Richmond A.S., A.R.G. Wylie, A.S. Laidlaw, F.O. Lively and N. O’Connell. 2013. Methane emissions from zero-grazed beef cattle on lowland and upland pastures. In: Proceedings of the Agricultural Research Forum, Tullamore, Ireland.

Richmond A.S., A.R.G. Wylie, A.S. Laidlaw, F.O. Lively and N. O’Connell. 2013. An evaluation of two sampling positions for estimating methane emissions from housed cattle using the SF6 tracer technique. In: Proceedings of the British Society of Animal Science Annual Meeting, Nottingham, UK.

Richmond A.S., A.R.G. Wylie, A.S. Laidlaw, F.O. Lively and N. O’Connell. 2013. Methane emissions from growing beef cattle grazing semi-natural upland and improved lowland pastures. In: Proceedings of the Greenhouse Gases & Animal Agriculture Conference, Dublin.

Roehe, R., Duthie, C-A., Rooke, J.A., Wallace, R.J., Hyslop, J.J., Ross, D.W., Waterhouse, A (2013) The association between growth and methane emissions of finishing beef cattle using an experimental trial designed to estimate breed and sire differences. In ‘Greenhouse Gases In Agriculture’, International conference held at University College Dublin, June 2013.

Roehe, R., Rooke, J.A., Duthie, C-A., Hyslop, J.J., Wallace, J.W., Ross, D.W. and Waterhouse, A. (2013) The influence of sire effects on methane emissions from finishing beef cattle in an experiment using divergent sire breeds and diets. Proceedings of Annual Meeting BSAS, Nottingham, April 2013.

Roehe, R., Duthie, C-A., Rooke, J.A., Wallace, R.J., Hyslop, J.J., Ross, D.W., Waterhouse, A (2013) The association between growth and methane emissions of finishing beef cattle using an experimental trial designed to estimate breed and sire differences. In ‘Sustainable Intensification – the pathway to low Carbon farming’ proceeding of conference, Edinburgh, Sept 2013.

Rooke, J.A., Wallace, R.J., Duthie, C-A., Ross, D.W., Hyslop, J.J., Waterhouse T. and Roehe, R. (2013) Methane and hydrogen emissions from finishing cattle fed either a forage- or concentrate-based diets. In ‘Greenhouse Gases In Agriculture’, International conference held at University College Dublin, June 2013.

Rooke, J.A., Duthie, C-A., Hyslop, J.J. Ross, D.W., Waterhouse, A. and Roehe, R. (2013) Methane emissions from finishing cattle fed either a forage-based or high concentrate diet. Proceedings of Annual Meeting BSAS, Nottingham, April 2013.

Rooke, J.A., Wallace, R.J., Duthie, C-A., Ross, D.W., Hyslop, J.J., Waterhouse T. and Roehe, R. (2013) Methane and hydrogen emissions from finishing cattle fed either a forage- or concentrate-based diets. In ‘Sustainable Intensification – the pathway to low Carbon farming’ proceeding of conference, Edinburgh, Sept 2013.


Troy, S., Rooke, J.A., Duthie, C-A., Ross, D.W., Hyslop, J.J. Roehe, R. and Waterhouse T. (2013) Measurement of methane from finishing cattle fed either a forage-based or high concentrate diet from both feeder-mounted samplers and respiration chambers In ‘Greenhouse Gases In Agriculture’, International conference held at University College Dublin, June 2013.

Troy, S., Rooke, J.A., Duthie, C-A., Ross, D.W., Hyslop, J.J. Roehe, R. and Waterhouse T. (2013) Measurement of methane from finishing cattle fed either a forage-based or high concentrate diet from both feeder-mounted samplers and respiration chambers In ‘Sustainable Intensification – the pathway to low Carbon farming’ proceeding of conference, Edinburgh, Sept 2013.

Wallace, R.J., Rooke, J.A., Duthie, C-A., Hyslop J.J., Ross, D.W., Waterhouse, A. and Roehe R. (2013) The ratio of archaeal and bacterial 16S rRNA genes in ruminal digesta as determined by qPCR correlates with methane emissions from beef cattle, but the relation is highly dependent on diet In ‘Greenhouse Gases In Agriculture’, International conference held at University College Dublin, June 2013.

Wallace, R.J., Rooke, J.A., Duthie, C-A., Hyslop, J.J., Waterhouse, A. and Roehe, R. (2013) Analysis of ruminal digesta post mortem by qPCR targeting archaeal and bacterial 16S rRNA genes enables the post hoc estimation of methane emissions from beef cattle Proceedings of Annual Meeting BSAS, Nottingham, April 2013.

Zhao, Y.G., R. Annett, T. Yan and N.E. O’Connell. 2013. Effects of breed and forage type on methane emissions from hill replacement ewes. In: The proceedings of the 5th Greenhouse Gases and Animal Agriculture, p495, Dublin, Ireland.

Zhao, Y G, R Annett, A Aubry, N E O'Connell and T Yan. 2014. Effects of forage and breed types on the efficiency of utilisation of energy in hill replacement ewes. Proceedings of the British Society of Animal Science, p 24.

Zhao, Y G, R Annett, A Aubry, N E O'Connell and T Yan. 2014. Effects of forage and breed types on the efficiency of utilisation of nitrogen in hill replacement ewes. Proceedings of the British Society of Animal Science, p 28.


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