Data quality assessment of pig movements in the Norwegian Livestock Register reveals challenges for outbreak preparedness.

Background: Animal movements are an important pathway for the spread of pig diseases. Traceability systems provide data for the competent authorities to prevent and manage infectious disease outbreaks. In Norway, batch-level pig movements are documented in the Norwegian Livestock Register. The purpose of our study was to evaluate the quality of pig movement data in the Norwegian Livestock Register for 2022. We assessed the quality in terms of accuracy, completeness and timeliness for the purpose of outbreak preparedness. We used secondary governmental and industry registers for external validation.

Results: The Norwegian Livestock Register contained all the variables needed for tracing pig movements between farms and to slaughterhouses. The register had high accuracy for individual records of between farm movements, however, it lacked completeness. By comparing movements between farms to the Register for Carcass Deliveries, we found that 41% of sending farms lacked registrations in the Norwegian Livestock Register. Similarly, a quarter of all finisher farms did not report receiving any pigs for 2022. Using indicator farms, we show that three slaughterhouses did not correctly report live animal movements between farms on behalf of owners. Lastly, we found that 41% of records were registered after the deadline of seven days.

Conclusions: The competent authorities need accurate, complete, and timely data on livestock movements to control rapidly spreading diseases. Based on our assessment, we found that pig movement data in the Norwegian Livestock Register lacked sufficient quality to serve this purpose. Instead, we recommend that movement data are additionally obtained through traditional epidemiological methods during outbreaks, such as from primary records on farms. Reporting from slaughterhouses and farms in sow pools should be targeted for improving the completeness and timeliness of the register data. Finally, the measures presented here should be used to develop real-time monitoring of the data quality.