Table 3. Outline of variables included in a questionnaire addressed to pig farms.
| Variable | Levels (if applicable) |
| Production unit type (and number of sources where applicable) | Farrow-finish/wean-finish/grow-finish |
| All-in/All-out pig flow | By unit/ building/room/pen |
| Number of finisher places | value |
| Distance to next pig unit (km) | value |
| Experience of senior stockman (years) | value |
| Ongoing training of stockmen | Yes/No |
| Accommodation systems (for weaning −30 kg, and 30 kg – slaughter) | Fully slatted/part slatted/straw yards/assisted ventilation |
| Number of times pigs moved after weaning | value |
| Number of times pigs mixed after weaning | value |
| Is airspace shared by pigs of >1 month age gap? | Yes/no |
| Maximum number of pigs in shared airspace | value |
| Feeding regime (for 7–30 kg, for 30–50 kg, and for 50 kg – slaughter) | Meal/pellets/wet feed |
| Home-mixed/purchased compound/by-product | |
| Ad libitum/restrict fed | |
| Medication: number at group level | Product/duration/in feed or water/reason |
| Medication: individual treatments: | Number in past week/reason |
| Farmer observations of disease (main effect: none, few, many; where an age effect requested this is 7–30 kg & >30 kg; data requested for 2008 & 2007) | Scours (by age)/sneezing (by age)/coughing (by age)/dyspnoea (by age)/meningitis/wasting (by age)/sudden deaths (by age)/porcine dermatitis and nephropathy syndrome (PDNS)/other |
| Farmer or herd vet knowledge of specific disease status (believed present, confirmed by vet, believed absent, not known) | porcine reproductive and respiratory syndrome (PRRS))/A. pleuropneumoniae (APP)/Glasser's Disease/enzootic pneumonia (EP)/post-weaning multisystemic wasting syndrome (PMWS) |
| Vaccination of finisher pigs | Absence of any vaccination/EP (one or 2 dose regime)/Porcine circovirus type 2 (PCV2)/PRRS/Glasser's Disease/Ileitis/Other |
| Post-weaning mortality | Values for 2008, 2007, 2006 |
| Mortality recording system type | Computer/other |
| Vet health plan in place on unit | Yes/No |
Outline of variables included in a questionnaire addressed to pig farms defined as case (pleurisy prevalence consistently >10%) or control (pleurisy prevalence consistently <5%) to seek relationships between pleurisy and production unit type, key indicators of general management, and health observations.