to read the full report - Ecolateral by Peter Jones

52
Evaluation of Opportunities for Converting Indigenous UK Wastes to Wastes and Energy
AEA/ED45551/Issue 1
Although there is considerable variation in the residue output of livestock, as it is species dependent, age
and type of animal dependent, and residue collection system dependent, some generalisations can be
made:
• Where cows are housed, usually for part of the winter, and for regular portions of each day if it is
a dairy herd, the slurry is usually collected mixed with straw, using a scraper system. Slurry is
collected on around 18% of beef cattle farms, and 66% of dairy cattle farms. The addition of
straw will alter the total solid composition, as will the type of housing system in use. Rinsing of
the area is not common, so dilution of the slurry with water is minimal. 75
• Most pigs are housed for the majority of their lives, often 100%, making collection of their
residues viable. However variation in the types of housing, and methods of farming mean that
there are large variations of total solids and organic dry matter. Larger pig farms usually collect
the waste as a liquid slurry, at a high dilution. Other methods include the use of a scraper system
which produces a higher dry content. 75
• Egg laying poultry do not use bedding, and therefore their residues are quite wet and count as
wet residue. In contract poultry raised for meat will use bedding, often sawdust and wood
shavings, and considerable time elapses before the residue is collected, permitting significant
drying to occur. Thus these residues are considered to be dry residues.
• Sheep are largely un-housed, so it is not possible to collect their residues. For this reason they
have not been considered any further in this report.
Livestock can be grouped according to the category of animal and the type of collection system that is
likely to be used. Such a scaling system has been used previously to estimate the potential methane
yield of agricultural residues for Defra. 76 These scaling factors can be applied to the total number of
livestock, to begin to estimate the regional arisings of residues.
The total current livestock numbers are detailed in Table 21, and have been taken from the Farm Surveys
of England, Scotland, Wales and Northern Ireland. Further breakdown of the numbers can be found in
Appendix 1, where more detailed categorisation has been used. 77
Table 21 Livestock numbers for the UK, on a regional basis.
Cattle Pigs Total Fowls
Region
(‘000 head) (‘000 head) (‘000 head)
East Midlands 519 418 24,178
East of England 220 1,066 25,312
North East 286 85 2,428
North West 965 160 8,263
South East inc. London 461 259 9,867
South West 1,804 480 18,316
West Midlands 760 235 16,602
Yorkshire and Humber 583 1,239 14,408
England - Total 5,598 3,943 119,374
Northern Ireland 1,623 402 16,322
Scotland 1,897 457 8,308
Wales 1,323 25 5,836
UK - Total 10,440 4,828 150, 000
75 Feedstocks for Anaerobic Digestion, AD-NETT Report 2000.
76 Assessment of Methane Management and Recovery Options for Livestock Manures and Slurries, 2005, AEA for Defra. Figures calculated from
English data. Applied uniformly here to England, Scotland, Wales and Northern Ireland.
77 June Survey of Agriculture and Horticulture (Land use, livestock and labour on agricultural holdings at 1 June 2008) England – Final Results, Defra,
Published 20 November 2008. Welsh Agricultural Statistics 2007, http://wales.gov.uk/topics/statistics/publications/was2007/?lang=en, 2008 June
Agricultural and Horticultural Census for Scotland, http://www.scotland.gov.uk/Publications/2008/06/19154131/1 , The Agricultural Census in Northern
Ireland, 2008 http://www.dardni.gov.uk/da1_09_25820__08.09.160_agricultural_census_in_ni_-_results_for_june_2008_amended.pdf.pdf