Table 6.

Results from logistic mixed regression for the detection of BCoV ¹ in nasopharyngeal swab samples from 33 Swiss veal calf farms regarding TI_DDD ² and age ³, as well as the interaction between antimicrobial treatment incidence and age. Additionally, the regression slope ⁴ for antimicrobial treatment incidence (i.e., the increase in BCoV prevalence with increasing daily dosage) is provided for each age ³ class separately.

Parameter	Category	Estimate	Standard Error	z-Value	p-Value
Intercept		0.62	0.33	1.89	0.059
TIDDD 2 Age 3		0.01	0.01	1.44	0.149
	>100 days	−1.88	0.35	−5.41	<0.001
TIDDD: Age	>100 days	−0.003	0.01	−0.27	0.788
Regression slope for each age class 4
Younger	≤100 days	0.01	0.01	1.44	0.149
Older	>100 days	0.01	0.01	1.44	0.253

¹ Bovine coronavirus. ² Antimicrobial treatment incidence of defined daily doses per animal-year (ddd/ay; EMA, 2013, 2016). ³ Dichotomized at 100 days according to bimodal distribution. ⁴ Increase in BCoV-positive swab samples (%) with increasing TI_DDD.