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Investigation of Strategies for the Introduction and Transportation of Replacement Gilts on Southern Ontario Sow Farms

28 November 2012

Scientists in Canada have highlighted that the overall biosecurity strategy on a farm is more important than the implementation of individual practices in considering the control of porcine reproductive and respiratory syndrome (PRRS) and other diseases in breeding pigs.

PRRS is of major concern to the swine industry; infection with the virus can lead to production losses, morbidity and mortality within swine operations, according to Kate Bottoms of the University of Guelph in Canada and colleagues there and at Iowa State University in the US in their recent paper in BMC Veterinary Research. They continue that biosecurity practices related to the management of replacement animals are important for the prevention and control of the PRRS virus, as well as other diseases.

The objectives of this study were:

  • to describe individual biosecurity practices related to the introduction and transportation of replacement gilts on southern Ontario sow farms, and
  • to understand patterns in the implementation of these practices.

The second objective was accomplished using multiple correspondence analysis (MCA), which allows visualisation of the relationships between individual practices and provides information about which practices frequently occur together, and which practices rarely occur together. These patterns constitute strategies for the implementation of biosecurity practices related to the introduction and transportation of replacement gilts.

Data were collected using version 2 of the Production Animal Disease Risk Assessment Program's survey for the breeding herd. Two subsets of variables were retained for analysis; one subset pertained to how replacements were managed upon arrival to the farm, and the other pertained to the transportation of genetic animals.

For both subsets of variables, the results of the MCA procedure were similar; in both solutions, the first dimension separated herds that were closed with respect to replacement animals from herds that were open, and the second dimension described how open herds managed replacements.

The most interesting finding of this study was that, in some cases where a risky practice was being implemented, it was closely associated with other biosecurity practices that may mitigate that risk.

The findings from this approach suggest that one cannot always examine biosecurity on a variable-by-variable basis, concluded Bottoms and co-authors. Even if a practice that is generally considered high-risk is being implemented, it may be balanced by other practices that mitigate that risk. Thus, the overall biosecurity strategy on a farm must be considered instead of only examining the implementation of individual practices.


Bottoms K., Z. Poljak, C. Dewey, R. Deardon, D. Holtkamp and R. Friendship. 2012. Investigation of strategies for the introduction and transportation of replacement gilts on southern Ontario sow farms. BMC Veterinary Research, 8:217. doi:10.1186/1746-6148-8-217

Further Reading

You can view the full report (as a provisional PDF) by clicking here.

Find out more information on Porcine Reproductive Respiratory Syndrome (PRRS) by clicking here.

November 2012

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