A Retrospective Analysis of Postmortem Salmonella Dublin Cases in Dairy Cattle in British Columbia

Table 3

Adjusted odds ratios for positive S. Dublin status.

Category	Subcategory	Adjusted for clustering on clinic and farm
		OR^1	95% CI
Season	Fall	Ref^2	—
	Winter	0.80	0.38–1.65
	Spring	0.64	0.30–1.38
	Summer	0.79	0.38–1.65
Farm region	Fraser Valley	Ref^2	—
	Okanagan	0.47	0.01–16.35
	Vancouver Island	1.09	0.00–20,245.69
	Creston	0	0-NA^3
	Bulkley Valley	0	0-NA^3
Age	Older Heifer/adult	Ref^2	—
	Fetus	3.10	0.55–17.15
	Neonates	8.28	1.55–44.32
	Calf	38.43	7.26–203.64
	Young Heifer	10.01	1.50–68.09
Breed	Holstein	Ref^2	—
	Jersey	1.07	0.13–8.69
	Brown Swiss	7.52	0.00–117,717.12
	Ayrshire	0.00	0.13–8.69

¹Odds ratio (OR) with 95% confidence interval (CI). ²Reference category. ³Insufficent power to make an estimate.