Table 1.
Distribution and odds ratios of variables with P ⩽ 0·20 in univariable random logistic regression models of factors associated with being Cryptosporidium spp. positive in 221 calves from 13 organic and 13 conventional herds
| Variable | Number of observations | OR (95% CI) | P | |
|---|---|---|---|---|
| Organic | Conventional | |||
| Calf level | ||||
| Age, days* | 2–65 | 3–60 | 1·03 (1·01–1·05) | 0·003 |
| Herd level | ||||
| Number of cows* | 41–111 | 41–131 | 0·99 (0·98–1·00) | 0·108 |
| Calf cryptosporidial prevalence (%) | 0·000 | |||
| <33 | 30 | 42 | 1 | |
| 33–67 | 57 | 35 | 3·10 (1·57–6·12) | |
| >67 | 27 | 30 | 12·14 (5·25–28·04) | |
| Number of preweaned calves at sampling | 0·089 | |||
| <11 | 28 | 38 | 1 | |
| 11–20 | 66 | 50 | 1·14 (0·51–2·57) | |
| >20 | 20 | 19 | 0·35 (0·11–1·10) | |
| Farm inspection | ||||
| Number of fattening calves per feeding trough | 0·144 | |||
| 1 | 64 | 59 | 1 | |
| >1 | 40 | 39 | 2·23 (1·00–4·97) | |
| No data | 10 | 9 | 1·23 (0·31–4·94) | |
| Homogenous density in group pens | 0·139† | |||
| Yes | 84 | 88 | 1 | |
| No | 10 | 9 | 1·53 (0·39–5·97) | |
| No data | 20 | 10 | 4·17 (0·81–21·52) | |
| Cleanliness of bedding/pen floors (% surface that is clean) | 0·017 | |||
| <20 | 7 | 14 | 1 | |
| 20–50 | 19 | 26 | 0·15 (0·04–0·66) | |
| >50 | 88 | 39 | 0·15 (0·04–0·57) | |
| High variability between pens | 0 | 28 | 0·39 (0·08–1·88) | |
| Separate area for feeding | 0·158† | |||
| Yes | 102 | 91 | 1 | |
| No | 5 | 9 | 1·55 (0·35–6·86) | |
| No data | 7 | 7 | 6·83 (0·81–57·6) | |
| Animals with diarrhoea (%)‡§ | 0·197† | |||
| 0 | 14 | 44 | 1 | |
| 1–10 | 32 | 22 | 1·46 (0·54–3·92) | |
| 11–29 | 40 | 7 | 0·69 (0·24–1·97) | |
| 30–50 | 18 | 26 | 0·89 (0·31–2·54) | |
| No data | 10 | 8 | 4·43 (0·93–21·01) | |
| Dirty animals (%)‡§ | 0·093 | |||
| <20 | 64 | 16 | 1 | |
| 20–40 | 50 | 37 | 2·26 (0·97–5·30) | |
| >40 | 0 | 54 | 2·53 (0·95–6·70) | |
| Questionnaire | ||||
| Bought livestock last 2 years | 0·090 | |||
| No | 59 | 29 | 1 | |
| Yes | 55 | 78 | 0·50 (0·23–1·11) | |
| Attitude towards biosecurity | 0·069 | |||
| Important | 51 | 72 | 1 | |
| Very important | 63 | 35 | 0·49 (0·23–1·06) | |
| Preweaned calf management | 0·063 | |||
| Single pens | 0 | 24 | 1 | |
| Single and group pens | 61 | 74 | 0·94 (0·32–2·81) | |
| Group pens | 28 | 0 | 0·31 (0·07–1·35) | |
| Group pen with nursing cow | 25 | 9 | 2·11 (0·55–8·10) | |
| Cleaning of group pens | 0·131 | |||
| Daily | 28 | 15 | 1 | |
| Once per week | 30 | 8 | 1·34 (0·41–4·36) | |
| Every 2 weeks | 15 | 37 | 3·87 (1·29–11·57) | |
| Less often than every 2 weeks | 41 | 22 | 2·48 (0·88–7·03) | |
| No group pens | 0 | 25 | 2·00 (0·54–7·37) | |
OR, Odds ratio; CI, confidence interval.
*
Continuous variable, range.
†
‘No data’ level is the ‘significant’ one.
‡
Includes all sampled animals within a farm.
§
Point 29a in Supplementary Appendix S1, categorized to produce an approximately equal number of animals in each category.