Combined spatial and network analyses of British pig movement data
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Research partner: Scottish Agricultural College (SAC)
Sponsor: BPEX
Project duration: 2009 – 2012
During the last decade, the British pig industry has shown a proactive attitude concerning the health and welfare of pigs, and the implementation of an abattoir monitoring scheme (BPHS) has provided producers and veterinarians with valuable information on farm disease prevalence. However, pig production is not a closed system restricted by farm or geographical boundaries and animal movements may contribute to disease transmission. Pig movement records have become a source of surveillance data available for epidemiological analysis. These data allow the identification of ‘active’ pig holdings and provide information about their contacts (pig holding network) and their geographical location. Together, the abattoir disease monitoring and the pig movement data provide an opportunity to improve the industry’s knowledge about 1) the demographic, spatial and network structure of the British pig industry and 2) the spatial and network characteristics of endemic diseases such as Enzootic Pneumonia.
During the year pig movement records for the period 2006-2008 were obtained from RADAR*, submitted to a cleansing process, and compared with privately-held data of major pig groups to check the quality and representativeness of RADAR data. The movement data was then used to characterise pig farms in terms of the total number of pigs moved per year as a proxy for farm size.
The objective of this ongoing process is to study the occurrence and patterns of links between the different types and sizes of holdings, different regions and different time periods. Future work will study the effect that the farms’ demographic, spatial and network characteristics have on the disease prevalence.
Key findings to date
- Approximately 200,000 movements and 14 million pigs were transported per year (8M from farm to abattoirs; 5M between farms and ~150,000 from farm to markets/showground)
- A total of 18,565 pig farms reported pig movements, from 2,470 Large (13%), 3,466 Medium (19%) and 12,609 Small (68%) producers
- Large producers were found to be responsible for the majority of farm-farm and farm-abattoir movements; the medium producers have the higher proportion of movements between farm and markets/showground; movements from small to medium and large producers are reported and they should be explored because they might pose a higher risk of disease transmission
- There are differences in the geographical farm distribution, eg small vs. large producers.
A better understanding of the geographical distribution and the type of links between farms (eg small vs. large) will be a useful outcome of this study. Later in the project these results will allow the identification of geographical areas and communities of the network where common spatial, network or farm characteristics might be responsible for the disease prevalence observed through the abattoir monitoring schemes. The outcomes of the project may be used to improve disease control strategies or to optimise animal trade between pig groups.
* RADAR stands for Rapid Analysis and Detection of Animal-related Risks. It is a new information management system, which has been developed to collect and collate veterinary surveillance data from many different sources around the UK. It provides specialist tools for the analysis of surveillance data and publishes reports highlighting the risks and distribution of veterinary threats to the public and animal health and welfare.
Data validation process and descriptive analysis
preliminary results - download presentation
Page last updated
08-Apr-2011