Exploring the role of auction markets in cattle movements within Great Britain

doi:10.1016/j.prevetmed.2007.04.011

Preventive Veterinary Medicine

Volume 81, Issues 1–3, 14 September 2007, Pages 21-37

https://doi.org/10.1016/j.prevetmed.2007.04.011 Get rights and content

Abstract

Within Great Britain cattle are often traded at regional markets, of which there are approximately 200 located throughout England, Scotland and Wales. The movement of animals through markets was important in the spread of foot-and-mouth disease (FMD) virus during the 2001 GB outbreak. Here, we describe the movements of cattle to and from markets for 2002–2004 and, using social network analysis, we construct networks based on these movements. In 2002, 56,227 animal holdings (AH) sent cattle to 222 cattle auction markets, compared to 58,476 AH and 187 auction markets in 2004. Auction markets vary considerably in their trading with AH. The majority of markets received animals from less than 50 AH, but one received animals from as many as 6155 AH during a year. The distances travelled between origin AH and destination AH when cattle move “directly” were found to be significantly shorter compared to distances between origin and destination AH where the movement occurred via a market. However, the vast majority of distances moved, for both types of movements, were less than 50 km. Some auction markets appear as highly connected premises within the contact network and are associated with high betweenness scores. However AH also occupy positions central to the contact network. The variation in the characteristics and role of individual markets within the contact network suggests important differences in risk of disease transmission associated with each market. Inclusion of network parameters, when considering the risk associated with moving cattle through auction markets may enhance the development of effective targeted disease control strategies.

Introduction

During their life, a large proportion of cattle move at least once between the approximate 80,000 cattle holdings within Great Britain (Mitchell et al., 2005). This movement of livestock between premises represents a contact by which infectious diseases may be transmitted. Whilst farmers may be aware of the risks of transmitting disease via livestock movements, a degree of movement is necessary within the modern livestock industry. For example, many farms that breed suckler or dairy cows do not have the facilities, or the availability of straw or feed, to finish all young-stock produced by the herd. Many within the industry therefore view the movement of store cattle between animal holdings (AH), which often occurs at auction markets, as vital to the sustainability and profitability of both the beef and dairy industries.

The risk posed by animal movements was clearly demonstrated in the initial stages of the foot-and-mouth disease (FMD) outbreak in 2001 in GB. Retrospective analysis indicated that initial spread was largely attributed to movement and mixing of animals in livestock markets (Ferguson et al., 2001, Gibbens et al., 2001, Mansley et al., 2001). In addition, movements to and from auction markets frequently occurred over long distances, thereby disseminating FMD to geographically separate areas (Kao, 2002). Cessation of auctions during the outbreak and, subsequently, an increased requirement for markets to improve bio-security, surveillance and movement recording has reportedly led to the closure of 19% of livestock markets in GB (Garner, 2003).

Auction markets play key roles in the livestock industry and within rural communities. They are a means for establishing competitive bidding so as to attain the best prices for stock and the sale of cattle at some of the larger markets is associated with prestige within the industry. Auction markets also feature as important social gatherings within the farming community. In order that appropriate surveillance and restrictions are applied to auction market trading it is essential to assess their current potential role as conduits of infection within the livestock industry.

Previous analyses have been conducted using data on movements in the period leading up to identification of FMD virus in the 2001 epidemic in GB (Ortiz-Pelaez et al., 2006, Shirley and Rushton, 2005). These studies found markets to be associated with large numbers of animal movements, characterised by high betweenness (Ortiz-Pelaez et al., 2006), which is defined as the frequency with which a node falls on the shortest path between pairs of other nodes (Freeman, 1978/1979). However, it is not known to what extent auction markets feature in recent cattle movements; the temporary closure of markets during 2001 led to speculation within the industry that numbers of cattle moving through markets would decline. However, this suggestion has not been fully evaluated.

The potential for analysis of cattle movements in Great Britain has been made possible through access to data in the cattle tracing system (CTS) which contains cattle movement records for Great Britain. Using CTS data for 2002–2004, we initially describe and characterise movements between different premises types in terms of the number and volume of cattle movements. To assess the contribution of movements through markets we compared these to the movements of cattle directly between AH. We compare a range of features of movements, including the distances cattle move. We then construct contact networks and use social network analysis to explore structural features associated with position of markets within the contact network of animal movements occurring in 2002–2004.

Section snippets

Market location data

A list of all British cattle markets addresses were provided by the Livestock Auctioneers Association (LAA). Auction markets currently trading cattle was verified by telephone interview. Location data from postal addresses were obtained using QuickAddress Batch v3.3 (QAS, London, UK).

Movement data source

In Great Britain, all cattle must be individually identified and animal keepers must report each animal's birth, movements and death to a centralised data recording service. Data on movements of cattle were derived

Market locations

The location of 159 auction markets registered with the LAA and that traded cattle in 2004 is illustrated in Fig. 2. Within the RADAR database it was possible to identify 222 auction markets trading cattle in 2002 and 187 in 2004. Only 163 of these auction markets were present in both 2002 and 2004. The difference between the LAA and RADAR data arises where auction markets which do not usually trade cattle (and therefore are not registered as cattle markets with the LAA) undertake the sale of

Discussion

Confirming what has previously been reported using movement data from the period prior to the detection of FMD in Great Britain in 2001 (Ortiz-Pelaez et al., 2006), we have demonstrated that auction markets continue to feature as hubs connecting large numbers of AH. However, the number of markets acting in these highly connected roles only represents a relatively small proportion of markets holding cattle sales within any 1 week and although a small number of markets had extremely high

Conclusion

This paper has considered (largely qualitatively) several features of cattle movements associated with auction markets. Although markets may play a role in dispersal of disease between livestock premises, individual markets vary in their contribution to contact networks, distances over which animals are transported and the number and volume of cattle movements. Further analysis taking into account temporal, spatial and network parameters and the relative risk market movements pose compared to

Acknowledgments

We thank the Livestock Auctioneers Association, and a number of auctioneers for responding to requests for information and data. This work was supported by research grant VTRI VT0103 from the higher Education Funding Council for England and the Department for Environment, Food, and Rural Affairs. The authors also wish to thank DEFRA for the provision of the BCMS CTS data from RADAR.

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Exploring the role of auction markets in cattle movements within Great Britain

Abstract

Introduction

Section snippets

Market location data

Movement data source

Market locations

Discussion

Conclusion

Acknowledgments

Soc. Networks

Soc. Sci. Med.

Soc. Networks

Trends Microbiol.

Prev. Vet. Med.

Prev. Vet. Med.

Error and attack tolerance of complex networks

Nature

Identifying and Tracking Livestock in England

Network analysis of cattle movement in Great Britain

Proc. Soc. Vet. Epidemiol. Prev. Med.

The foot-and-mouth epidemic in Great Britain: pattern of spread and impact of interventions

Science

Cautious welcome for 6-day standstill switch

Farmers Weekly