Farm animal networks: unraveling the contact structure of the British sheep population.

The spatial and temporal dynamics of many farm animal diseases depend both on disease specific parameters and on the underlying contact structure between farms. Whilst many models for farm animal diseases focus on obtaining and estimating disease transmission parameters, relatively little attention has been given to modelling the underlying network of contacts. In this paper, we present an initial analysis of two relations underlying the contact network of individual sheep breeds in Great Britain. The first relation is based on geographical proximity and the second is based on attendance at agricultural shows. These relations are combined to give a risk-potential network that is based on these two levels of interaction. The structure of each network is investigated using techniques developed in graph theory and social network analysis.