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Table 6 Exposure variables included in the risk factor analysis for PRRS infection

From: Risk factors for porcine reproductive and respiratory syndrome virus infection and resulting challenges for effective disease surveillance

Variable group Variable description
1. General farm information Geographic location (by region)
Number of sites (one/multiple)
Herd size (measured by number of sows)
Pig density (total number of pigs within 10 km radius from the farm)
Farm type: outdoor/ indoor
2. Herd health Farmers perception:
Herd vaccination program (PPV, PRRS)
Type of PRRS vaccine used (none/killed virus /live virus)
Results from serology and PCR:
Serological results: APP, SI (avian-like H1N1, H1N2, H3N2)
PCR results: PCV2 (PCR)
3. General management practices Herd environment:
Ventilation type (natural/artificial/both)
Lightening (natural/artificial/both)
Presence of slurry system (yes/no)
Use of straw yards at any stage of the production (yes/no)
Presence of other animal species on the farm (yes/no)
Weaners stocking density/pen
Growers stocking density/pen
Finishers stocking density/pen
Herd management:
Number of movements between weaning and finishing
Mixing of pigs at any stage of the production (yes/no)
All in all out system at any stage of the production (yes/no)
Use of sick/hospital pens on farm (yes/no)
Routine cross-fostering performed (yes/no)
4. Genetics Breed composition (percentage of breeds in the average finishing pig):
Large White (LW)
Landrace (LD)
Pietrain (P)
Duroc (D)
Hampshire (H)
Miesham (M)
5. Biosecurity Possible route of disease introduction through people:
Number of people working on the farm
Average number of visitors/month
Number of days pig free
Use of protective clothes (yes/no)
Use of boot dips (yes/no)
Presence of fences around the farm (yes/no)
Allowed parking on the farm (yes/no)
Possible route of disease introduction through animals:
Purchase of boars (yes/no)
Purchase of gilts (yes/no)
Purchase of semen (yes/no)
  Disposal of dead pigs (collection/incineration/other)