Table 2.

Results of multivariable negative binomial modelling of within-farm prevalence of Cryptosporidium parvum shedding on management factors significant at the 25% level in unconditional analysis

Predictor	Risk ratio	95% CI	Robust S.E.	P
Use of calf scour prophylaxis in pregnant cowsa	1.70	1.30, 2.22	0.23	<0.01
Concrete flooring in calf housing area	0.59	0.45, 0.76	0.08	<0.01
Feeding of milk replacer in first week of life	1.40	1.06, 1.85	0.20	0.02
Use of calf scour prophylaxis in calvesb	1.38	1.06, 1.81	0.19	0.02
Use of soap or detergent when washing feeding utensils	0.61	0.46, 0.82	0.09	<0.01

Data were collected from dairy calves 7–28 days old on 119 farms in southern Ontario. P-value of likelihood ratio test of alpha = 0 was 0.02 (<0.05).

^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.