Little is known regarding the types and frequencies of contact that exist between farms; however, it is likely that farms demonstrate considerable heterogeneity in contact. In this cross-sectional study, we explored the direct and indirect contact types and frequencies that exist between cattle farms within a region. The owners/managers of 56 farms located in a 10km by 10km study area in north-west England were administered an interview-based questionnaire between June and September 2005. Informationwas obtained relating to contact types and frequencies, including those involving animal movements, equipment sharing between farms and any contractors or companies visiting the farms. Maps of each farm were produced prior to visits (including additional premises used for stock) and contiguous neighbours identified from these. There was considerable variation in the connectedness of networks arising through different contact types. Some exhibited great connectivity, incorporating approximately 90% of the farms interviewed, whilst other networks appeared more fragmented, with multiple small components (sets of farms not linked with any others). A range of factors influencing contact between farms were identified. For example, contiguous farms were morelikely to be linked via other contacts, such as sharing of equipment, direct farm to farm animal movements and use of the same livestock dealers (p<0.00l, p=0.02 and p=0.1, respectively). The frequency of contacts was also investigated; it is likely that the amount of contact a farm receives from a company or contractor will impact on the potential for disease transmission to occur. Similarly, whether or not biosecurity is performed after contact (i.e. personnel, vehicles from that company) is also animportant consideration; minimal biosecurity performed infrequently would increase the likelihood of transmission of disease when compared with regular and thorough involvement in biosecurity practices. These findings lead to greater understanding of inter-farm contact. This may aid development of appropriate biosecurity practices and control procedures, and inform mathematical modelling of infectious diseases.
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