Results of a survey to estimate cattle movements and contact rates among beef herds in California, with reference to the potential spread and control of foot-and-mouth disease

Abstract

Objective-To estimate contact rates and movement variables for shipments of beef cattle to and from producer premises in California. Design-Cross-sectional survey. Sample Population-583 beef producers in California. Procedures-Questionnaires were developed and distributed to beef cattle producers in California.The study period was from April 20, 2005, through September 7 2006. Data from completed questionnaires were entered manually into an electronic format. Descriptive statistical analyses were performed. Results-Median number of interstate animal movements (movement of cattle into or out of California) was 0.17/mo; on the basis of this median, beef cattle were moved interstate > 2 times/y. Respondents kept beef cattle at up to 5 locations throughout the year. More than 40% of the movements from the respondents' premises were to a sale yard or auction facility. Conclusions and Clinical Relevance-Frequency of animal movements in this statewide study differed from values in another study of monthly shipments of animals to and from beef operations in 3 counties of California.The survey reported here revealed more frequent movements of animals to and from beef operations of all sizes. In addition, there were more high-risk indirect contacts on beef operations than has been reported previously. However, the number of low-risk indirect contacts was similar for small beef operations but less for large beef operations than has been reported elsewhere. Epidemic simulation models for California based on data in earlier studies likely underpredicted disease transmission involving beef herds.