Table 4. Characteristics of 6,143 farms inside versus outside the three multivariate persistent clusters.
| Farms inside clusters | Farms outside clusters | |||
|---|---|---|---|---|
| Actual No. (%) | Actual No (%) | p-value | ||
| Total number of farms | 551 (9.0) | 5,592 (91.0) | ||
| Conventional farms | 299 (54.3) | 3,120 (55.8) | ||
| Farms in the SPF register | 252 (45.7) | 2,472 (44.2) | 0.519 | |
| Farm type | Nucleus farms | 29 (5.3) | 199 (3.6) | |
| Production farms | 522 (94.7) | 5,393 (96.4) | 0.057 | |
| Production type | Farrow-to-finisher | 113 (20.5) | 1,317 (23.6) | |
| Sows and finishers | 16 (2.9) | 143 (2.6) | ||
| Sows and weaners | 32 (5.8) | 256 (4.6) | ||
| Sows | 11 (2.0) | 174 (3.1) | ||
| Weaner-finisher | 72 (13.1) | 843 (15.1) | ||
| Weaners | 24 (4.4) | 229 (4.1) | ||
| Finishers | 283 (51.4) | 2,630 (47.0) | 0.155 | |
| Farm size | ||||
| Presence of sows | Small (1–254) | 40 (23.3) | 473 (25.0) | |
| Medium (255–670) | 97 (56.4) | 946 (50.1) | ||
| Large (> 670) | 35 (20.3) | 471 (24.9) | 0.247 | |
| Presence of weaners | Small (1–783) | 48 (19.9) | 674 (25.5) | |
| Medium (784–2300) | 143 (59.3) | 1,315 (49.7) | ||
| Large (> 2300) | 50 (20.7) | 656 (24.8) | 0.016 | |
| Presence of finishers | Small (1–499) | 112 (23.1) | 1,230 (24.9) | |
| Medium (500–1600) | 226 (46.7) | 2,543 (51.6) | ||
| Large (> 1600) | 146 (30.2) | 1,160 (23.5) | 0.005 |
Three covariates (farm type, production type and farm size, in bold) were included one at a time in the multivariate scanning statistics. A chi-square test was performed to test for significant differences in the prevalence of farms inside compared to outside the clusters.