Table 1.
Non-response analyses of non-dairy sheep farms, comparison of participating and non-participating farms
| Numerical variables | Participating farms (N = 119) | Non-participating farms (N = 1193) | P value |
|---|---|---|---|
| Median | Median | ||
| Number of sheep | 191 | 167 | 0·05 |
| Cattle density (number of cattle/km2 in the municipality)* | 134·7 | 135·5 | 0·16 |
| Cattle density without veal calves (number of cattle/km2 in the municipality)* | 114·7 | 119·5 | 0·10 |
| Goat density (number of goats/km2 excluding own animals in a 5-km radius)* | 2·6 | 3·5 | 0·17 |
| Sheep density (number of sheep/km2 excluding own animals in a 5-km radius)* | 34·5 | 47·5 | 0·01 |
| Closest Q fever bulk-milk-positive dairy goat or dairy sheep farm (metres)* | 13 960 | 13 806 | 0·70 |
| Number Q fever bulk-milk-positive dairy goat or dairy sheep farms in a 5-km radius* | 0 (min = 0, max = 2) | 0 (min = 0, max = 4) | 0·62 |
| Number Q fever bulk-milk-positive dairy goat or dairy sheep farms in a 10-km radius* | 0 (min = 0, max = 4) | 0 (min = 0, max = 9) | 0·71 |
| Categorical variables | n (%) | n (%) | P value |
| Inside vaccination area | 20 (16·8) | 181 (15·2) | 0·64 |
| Outside vaccination area | 99 (83·2) | 1012 (84·8) | |
| Urbanization | |||
| Very high urban area*† | 0 (0·0) | 2 (0·2) | 0·37 |
| High urban area | 0 (0·0) | 3 (0·3) | |
| Moderate urban area | 4 (3·3) | 14 (1·2) | |
| Minor urban area | 7 (5·9) | 84 (7·0) | |
| Rural area | 108 (90·8) | 1086 (91·3) | |
| Province | |||
| Drenthe* | 4 (3·4) | 57 (4·8) | 0·52 |
| Flevoland | 1 (0·8) | 9 (0·8) | |
| Friesland | 18 (15·1) | 213 (17·9) | |
| Gelderland | 14 (11·8) | 170 (14·3) | |
| Groningen | 11 (9·2) | 93 (7·8) | |
| Limburg | 4 (3·4) | 23 (1·9) | |
| Noord-Brabant | 12 (10·1) | 74 (6·2) | |
| Noord-Holland | 29 (24·4) | 241 (20·3) | |
| Overijsel | 11 (9·2) | 86 (7·2) | |
| Utrecht | 2 (1·7) | 48 (4·1) | |
| Zeeland | 2 (1·7) | 49 (4·1) | |
| Zuid-Holland | 11 (9·2) | 126 (10·6) | |
N, Total number of individuals.
*
Four missing values at non-participating farms.
†
Urbanization degree: very high urban area >2500 addresses/km2; high urban area = 1500–2500 addresses/km2; moderate urban area = 1000–1500 addresses/km2; minor urban area = 500–1000 addresses/km2; rural area <500 addresses/km2.