Table 3.

Antibodies to PCV-2 in serum samples from three SPF-litters collected at the age of 3, 17 and 23 days and at 21 weeks^a

Litter	Piglet	IIF, 3 days	ELISA (% inhibition)
			3 days	17 days	23 days	21 weeks
1	4	–	4	0	0	97
	5b	+++	97	97	96	na
	6	–	38	0	0	na
	7	–	14	0	0	na
	8	–	13	1	4	98
	9b	+++	98	96	94	na
2	10	na	na	66	58	na
	11	++	98	99	92	93
	12	+++	100	95	94	88
	13	+++	99	88	88	na
	14	++	96	98	93	na
	15	+++	98	98	94	na
	16	na	na	94	82	na
	17	na	na	94	83	na
3	18	++	51	13	8	na
	19	++	72	46	21	na
	20	++	77	37	43	99
	21	+	53	15	0	na
	22	+	57	27	7	na
	23	+	45	14	14	na
	24	+	58	26	10	99
	25	++	72	42	22	na
	26	+	49	6	9	na
	27	+	51	15	9	94

^aAntibodies to PCV-2 were detected with ELISA (expressed as PI where <33% is negative, >44% is positive) and indirect immuno-fluorescence (IIF; (+++) strong positive to (+) weak positive and (−) negative), for details, see Section 2. na: no sample available.

^bPiglet nos. 5 and 9 were the offspring of, and received colostrum from, sow no. 2.