Table 3.
Univariable analysis results from mixed-effect regression with farm and group as the random effects [baseline (OR = 1·00) levels not shown]
| Variable | Level | OR | P value | 95% CI |
|---|---|---|---|---|
| Sex (baseline: female) | Castrated | 2·44 | 0·001 | 1·47–4·03 |
| Intact male | 0·78 | 0·224 | 0·52–1·17 | |
| Intact male, cf. castrate or female | 0·68 | 0·059 | 0·46–1·01 | |
| Herd type (baseline: suckler herd) | Fattener herd | 17·86 | 0·001 | 3·37–94·47 |
| Dairy herd | 4·95 | 0·116 | 0·67–36·41 | |
| Herd type (baseline: suckler herd) | Dairy or Fattener | 12·47 | 0·004 | 2·28–68·25 |
| Group size (baseline: 1–10) | 11–24 | 1·70 | 0·200 | 0·76–3·82 |
| 25–30 | 1·35 | 0·517 | 0·54–3·36 | |
| 30–40 | 1·21 | 0·689 | 0·47–3·14 | |
| 40–91 | 0·49 | 0·155 | 0·18–1·31 | |
| Cattle age group (months) (baseline: 0–2) | 3–6 | 2·85 | 0·038 | 1·06–7·68 |
| 7–12 | 3·69 | 0·010 | 1·37–9·97 | |
| 13–24 | 2·26 | 0·128 | 0·79–6·45 | |
| 25–34 | 2·25 | 0·160 | 0·73–6·94 | |
| Cattle age (months) | Continuous | 1·00 | 0·771 | 0·97–1·04 |
| Sample site (baseline: field) | House | 0·50 | 0·187 | 0·17–1·41 |
| House with outdoor pen | 1·05 | 0·929 | 0·35–3·20 | |
| Pen | 1·39 | 0·393 | 0·66–2·94 | |
| Pen, cf. house, field or house with outdoor pen | 1·86 | 0·009 | 1·17–2·97 | |
| Animal changed group since last visit | 0·65 | 0·006 | 0·47–0·88 | |
| VTEC O157 in surface water | 2·59 | <0·001 | 1·71–3·91 | |
| VTEC O157 in water-trough biofilm | 4·93 | <0·001 | 3·35–7·24 | |
| VTEC O157 in pooled environmental faeces | 2·58 | <0·001 | 1·87–3·55 | |
| Grass fed | 1·11 | 0·770 | 0·54–2·28 | |
| Hay fed | 0·52 | 0·471 | 0·08–3·13 | |
| Silage fed | 0·31 | <0·001 | 0·20–0·48 | |
| Straw fed | 2·48 | <0·001 | 1·51–4·06 | |
| Beans fed | 3·38 | 0·015 | 1·27–9·03 | |
| Milk fed | 0·15 | <0·001 | 0·05–0·43 | |
| Pulps fed | 0·23 | <0·001 | 0·14–0·37 | |
| Grains fed | 0·42 | <0·001 | 0·29–0·63 | |
| Root crops fed | 11·41 | <0·001 | 3·41–38·21 | |
| Concentrates fed | 0·62 | 0·062 | 0·38–1·02 | |
| Home-mix fed | 3·67 | <0·001 | 2·46–5·46 | |
| Dirty cattle (baseline: clean, score 1–2) | Score 3–5 | 1·53 | 0·003 | 1·15–2·03 |
| Fat cattle (baseline: thin, score 1–3) | Score 4–5 | 2·10 | <0·001 | 1·54–2·85 |
| Weaned in last 30 days | 0·84 | 0·753 | 0·27–2·55 | |
| Antibiotics in last 30 days | 0·64 | 0·566 | 0·14–2·96 | |
| Diet change in last 30 days | 1·45 | 0·069 | 0·97–2·16 | |
| Castrated in last 30 days | 1·97 | 0·453 | 0·33–11·67 | |
| Season (baseline: Dec.-Feb.) | Mar.-May | 0·49 | 0·002 | 0·31–0·76 |
| June-Aug. | 0·28 | <0·001 | 0·19–0·40 | |
| Sep.-Nov. | 0·38 | <0·001 | 0·27–0·53 | |
| VTEC O157 excreted by sampled individual at previous visit | 1·50 | 0·008 | 1·11–2·02 | |
| Surface water VTEC O157 positive at previous visit | 2·50 | <0·001 | 1·66–3·78 | |
| Biofilm VTEC O157 positive at previous visit | 0·61 | 0·051 | 0·37–1·00 | |
| Pooled environmental faeces VTEC O157 positive at previous visit | 2·15 | <0·001 | 1·48–3·13 |
OR, Odds ratio; CI, confidence interval; cf., compared with.
Significant variable results highlighted in bold. The results from levels of data created for missing values are not presented (all non-significant P < 0·05).