Table 3.
Final multivariable model* of the associations between use of vaccines and consumption of antimicrobials with respiratory indications (AC-RESP) in 836 Danish sow herds after controlling for production size, 2013. Group 0 (no vaccination) and small herd size were used as reference classes
| Variables and classes | AC-RESP (ADD/100 weaners/day) | Converted AC-RESP (ADD/100 weaners/day) | ||||
|---|---|---|---|---|---|---|
| Estimate of log-transformed outcome | Standard error | P-value | Mean estimate | Lower 95 % CI | Upper 95 % CI | |
| Intercept | 0.497 | 0.145 | <0.0001 | 1.6 | 1.2 | 2.2 |
| Combinations of vaccines | <0.0001 | |||||
| Group 0: PCV2 = 0 & MYC = 0 & LAW = 0 (n = 155)a,c | 0.000 | n.a. | 1.6 | n.a. | n.a. | |
| Group 1: PCV2 = 1 & MYC = 0 & LAW = 0 (n = 136)a | 0.404 | 0.177 | 2.5 | 1.7 | 3.5 | |
| Group 2: PCV2 = 0 & MYC = 1 & LAW = 0 (n = 134)b | 0.648 | 0.177 | 3.1 | 2.2 | 4.4 | |
| Group 3: PCV2 = 0 & MYC = 0 & LAW = 1 (n = 10)a,c | 0.160 | 0.490 | 1.9 | 0.7 | 5.0 | |
| Group 4: PCV2 = 1 & MYC = 1 & LAW = 0 (n = 349)b | 0.672 | 0.146 | 3.2 | 2.4 | 4.3 | |
| Group 5: PCV2 = 1 & MYC = 0 & LAW = 1 (n = 13)c | −0.994 | 0.434 | 0.6 | 0.3 | 1.4 | |
| Group 6: PCV2 = 0 & MYC = 1 & LAW = 1 (n = 6)a,b,c | −0.166 | 0.626 | 1.4 | 0.4 | 4.7 | |
| Group 7: PCV2 = 1 & MYC = 1 & LAW = 1 (n = 33)a,b,c | 0.220 | 0.289 | 2.0 | 1.2 | 3.6 | |
| Herd size (number of weaners pen places) | 0.06 | |||||
| Small (n = 235) | 0.000 | n.a. | 1.6 | n.a. | n.a. | |
| Medium (n = 331) | −0.261 | 0.129 | 1.3 | 1.0 | 1.6 | |
| Large (n = 270) | −0.295 | 0.136 | 1.2 | 0.9 | 1.6 | |
n.a. not applicable, PCV2 Porcine Circovirus Type 2, MYC Mycoplasma hyopneumoniae, LAW Lawsonia intracellularis
a, b, c – different letters indicate variable classes with significantly different parameter estimates of antimicrobial consumption according to an F-test
*Model statistics: R 2 = 0.04, F = 4.8, P = 0.001