Table 1.

Time schedules of vaccination and blood sampling

First experiment
Weeks after primary vaccination (or first blood sampling)	0	1	2	3	4	5	6	7	Sample size
+2 group	Primary*		Booster			BS			n = 21
+3 group	Primary*			Booster			BS		n = 16
+4 group	Primary*				Booster			BS	n = 19
Control group	BS**		Vaccination				BS		n = 15

*Experimental calves received primary vaccination at the age of 5–12 days

**In control group calves, blood was drawn at this period and calves received vaccination only once 2 weeks later