Table 6. Relations between different technical production parameters and interventions (model 1) and antimicrobial use (model 2) during the study period in the 51 veal calf farms. Model 3 relates the technical production parameters to antimicrobial use during all the 6 available production cycles (4 pre-study and 2 study cycles). The Netherlands 2009–2012.
| Models with the 2 study cycles | Model with 4 pre-study + 2 study cycles | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Model 1 with study arms | Model 2 with DDDA/C | Model 3 with DDDA/C | ||||||||
| Standardized Technical parameter | Effects | Est. a | SE b | P-value | Est. a | SE b | p-value | Est. a | SE b | P-value |
| Mortality | Intercept | -0.63 | 1.66 | 0.71 | 0.42 | 1.72 | 0.81 | -0.80 | 0.40 | 0.04 |
| Cycle (num) | -0.15 | 0.30 | 0.61 | -0.14 | 0.30 | 0.64 | 0.12 | 0.05 | 0.02 | |
| DDDA/C | - | - | - | 0.01 | 0.01 | 0.41 | 0.00 | 0.01 | 0.53 | |
| RAB | 0.19 | 0.45 | 0.68 | - | - | - | - | - | - | |
| RAB-CD | 0.52 | 0.44 | 0.24 | - | - | - | - | - | - | |
| Control | Ref. | - | - | - | - | - | - | - | - | |
| Mortality age c | Intercept | 6.78 | 15.74 | 0.67 | 11.94 | 16.46 | 0.47 | 1.98 | 4.80 | 0.68 |
| Cycle (num) | -1.66 | 2.78 | 0.55 | -1.65 | 2.81 | 0.56 | -0.38 | 0.64 | 0.55 | |
| DDDA/C | - | - | - | -0.13 | 0.15 | 0.38 | -0.06 | 0.07 | 0.43 | |
| RAB | 2.06 | 5.48 | 0.71 | - | - | - | - | - | - | |
| RAB-CD | 0.623 | 5.46 | 0.91 | - | - | - | - | - | - | |
| Control | Ref. | - | - | - | - | - | - | - | - | |
| Veterinary costs | Intercept | 0.27 | 2.37 | 0.91 | -3.15 | 2.33 | 0.18 | -4.22 | 0.68 | <0.01 |
| Cycle (num) | -0.01 | 0.42 | 0.98 | 0.07 | 0.39 | 0.85 | 0.30 | 0.09 | <0.01 | |
| DDDA/C | - | - | - | 0.09 | 0.02 | <0.01 | 0.08 | 0.01 | <0.01 | |
| RAB | -0.66 | 0.85 | 0.44 | - | - | - | - | - | - | |
| RAB-CD | 0.33 | 0.84 | 0.70 | - | - | - | - | - | - | |
| Control | Ref. | - | - | - | - | - | - | - | - | |
| Mean weight carcass | Intercept | 4.78 | 2.82 | 0.10 | 5.06 | 3.00 | 0.10 | 1.37 | 0.79 | 0.09 |
| Cycle (num) | -0.69 | 0.50 | 0.17 | -0.70 | 0.51 | 0.17 | -0.12 | 0.10 | 0.23 | |
| DDDA/C | - | - | - | -0.02 | 0.03 | 0.51 | -0.01 | 0.01 | 0.65 | |
| RAB | -1.18 | 1.01 | 0.25 | - | - | - | - | - | - | |
| RAB-CD | -0.34 | 0.99 | 0.74 | - | - | - | - | - | - | |
| Control | Ref. | - | - | - | - | - | - | - | - | |
| Duration of the cycle | Intercept | -0.90 | 4.90 | 0.86 | 5.28 | 5.04 | 0.30 | -5.70 | 2.21 | 0.01 |
| Cycle (num) | -0.37 | 0.85 | 0.66 | -0.47 | 0.83 | 0.58 | 1.43 | 0.50 | 0.01 | |
| DDDA/C | - | - | - | -0.09 | 0.05 | 0.06 | 0.11 | 0.04 | 0.01 | |
| DDDA/C-cycle interaction d | - | - | - | - | - | - | -0.04 | 0.01 | <0.01 | |
| RAB | 3.56 | 2.24 | 0.12 | - | - | - | - | - | - | |
| RAB-CD | 4.16 | 2.20 | 0.07 | - | - | - | - | - | - | |
| Control | Ref. | - | - | - | - | - | - | - | - | |
Results from linear mixed models accounting for clustering at farm level for each of the production parameters. Antimicrobial use as DDDA/C, defined daily dosages per animal per cycle. P-values <0.05 are in boldface. Ref., reference category of the variable. RAB, farms reducing antimicrobials by protocol; RAB-CD, farms reducing antimicrobials by protocol and applying a cleaning and disinfection program; Control, farms without interventions.
a Mean estimates obtained from mixed model for technical parameters with production cycle and DDDA/C or study arm as determinants.
b Standard error of mean estimates.
c Mortality age was only available from 2 sector integrations.
d Interaction terms are only presented when there is statistical significance (p<0.05).