Table 1.

Results of univariable analysis using negative binomial regression of each variable on the dependent variable (within-farm prevalence of C. parvum shedding)

Variable	Risk ratio	95% Confidence interval	P
Farm characteristics
Number of calves at time of sampling
1–3	0		0.001 (group)
4–6	2.1	1.4–3.1
>6	2.3	1.5–3.5
Number of milking cows
≤50	0.0		0.097 (group)
>50–70	1.1	0.7–1.8
>70–101	1.5	1.0–2.4
>101	1.6	1.1–2.5
Perinatal management
Percentage of calves fed colostrum by esophageal tube
<10%	0		0.24 (group)
10–4%	0.5	0.3–1.0
15–9%	0.9	0.8–1.5
30–100%	1.0	0.7–1.5
Scraping of calving pen floor during cleaning
No	0
Yes	0.8	0.5–1.1	0.181
Separation of calves from dams as soon as possible after birth
No	0
Yes	1.5	1.1–2.2	0.011
Use of calf scour prophylaxisa on cows before calving
No	0
Yes	1.5	1.1–2.1	0.009
Management of pre-weaned calves
Concrete flooring in calf housing area
No	0
Yes	0.6	0.5–0.8	0.002
Earth flooring in calf housing area
No	0
Yes	1.4	0.9–2.1	0.099
Feeding of milk replacer in first week of life
No	0.0
Yes	1.3	1.0–1.8	0.089
Feeding of starter in first week of life
No	0.0
Yes	1.2	0.9–1.7	0.207
Gravel flooring in calf housing area
No	0.0
Yes	1.4	1.0–1.9	0.061
Medications given to newborn calves
No	0.0
Yes	1.3	1.0–1.8	0.074
Sweeping of floor (earth-floored calf housing areas)
No	0.0
Yes	0.5	0.2–1.2	0.142
Type of coccidiostat fed in calf starter
None	0.0
Decoquinate	2.5	1.0–6.3	0.046
Monensin	3.3	1.3–8.6	(group)
Other	3.1	1.1–8.3
Use of First Defenseb Immucell, Portland, ME) for newborn calves
No	0.0
Yes	1.4	1.0–1.9	0.040
Use of injectable vitamin E and selenium for newborn calves
No	0.0
Yes	1.3	0.9–1.8	0.128
Vaccination of newborn calves against any pathogens
No	0.0
Yes	1.3	0.9–1.8	0.213
Washing of feeding utensils with disinfectant
No	0.0
Yes	1.2	0.9–1.7	0.167
Washing of feeding utensils with soap/detergent
No	0.0
Yes	0.7	0.5–0.9	0.015

Data were collected from dairy calves 7–28 days old on 119 farms in southern Ontario. Variables significant at the 25% level (P < 0.25) are shown. A full list of all variables tested for significance is available from the authors.

^aEcostar^® (Novartis Animal Health, Mississauga, Ontario): bovine rotavirus and coronavirus killed virus vaccine with Escherichia coli bacterin; or ScourGuard (Pfizer Animal Health, Orangeville, Ontario): vaccine containing inactivated bovine rotavirus and coronavirus, a K99 Escherichia coli bacterin, and Clostridium perfringens type C toxoid.

^bFirst Defense^® (Immucell, Portland, Maine): bovine coronavirus-E. coli antibody, bovine origin.