Table 6.

Unconditional associations between calving month and vaccine use in Canadian cow-calf herds (n = 131).

Vaccine use	Calving month	Odds Ratio a	Lower 95% CI	Upper 95% CI	p-value
Cows vaccinated against calf scours	Jan	(Ref)			0.02 b
	Feb	0.95	0.28	3.28	0.94
	Mar	0.73	0.26	2.05	0.55
	Apr	0.24	0.08	0.69	<0.01
	May	0.05	0.01	0.48	<0.01
	Nov-Dec	0.60	0.13	2.71	0.50
Weaned calves vaccinated against BVDV	Jan	(Ref)			<0.01 b
	Feb	0.19	0.05	0.66	<0.01
	Mar	0.17	0.06	0.50	<0.01
	Apr	0.58	0.19	1.81	0.35
	May	0.44	0.10	2.00	0.29
	Nov-Dec	0.36	0.08	1.74	0.21
Weaned calves vaccinated against IBR, BRSV, and PI3	Jan	(Ref)			<0.01 b
	Feb	0.23	0.07	0.82	0.02
	Mar	0.15	0.05	0.44	<0.01
	Apr	0.68	0.22	2.15	0.51
	May	0.44	0.10	2.00	0.29
	Nov-Dec	0.58	0.12	2.95	0.51
Suckling calves vaccinated against IBR (<3 months of age with injectable product)	Jan	(Ref)			<0.01 b
	Feb	3.30	0.98	11.1	0.05
	Mar	4.83	1.68	13.9	<0.01
	Apr	2.75	0.97	7.80	0.06
	May	0.53	0.09	2.94	0.46
	Nov-Dec	0.26	0.03	2.40	0.24

Bolded characters indicate a statistically significant values.

^aUnconditional odds ratio.

^bp-value for Wald test of categorical variable.