Table 2.

Results of the effect of Coxiella burnetii bulk tank milk antibody level measured before and after the occurrence of stillborn calves and perinatal death (including stillbirths) of calves in 24 Danish dairy herds.

Time difference (months) between S/P- test date and outcome interval#	n(total)	Outcome
		Stillborn			Dead within 24 hours
		n(cases)	Risk	P-value	n(cases)	Risk	P-value
-12	107	10	0.093	0.20	11	0.103	0.19
-11	250	17	0.068	0.88	18	0.072	0.76
-10	425	29	0.068	0.47	31	0.073	0.27
-9	546	34	0.062	0.44	37	0.068	0.26
-8	750	49	0.065	0.22	55	0.073	0.12
-7	907	57	0.063	0.12	65	0.072	0.07
-6	1065	71	0.067	0.39	80	0.075	0.34
-5	1266	83	0.066	0.16	94	0.074	0.11
-4	1472	90	0.061	0.85	103	0.070	0.51
-3	1725	98	0.057	0.46	112	0.065	0.58
-2	1949	107	0.055	0.23	121	0.062	0.38
-1	2196	120	0.055	0.45	134	0.061	0.73
0	2362	132	0.056	0.23	146	0.062	0.41
1	2098	114	0.054	0.27	127	0.061	0.49
2	1936	102	0.053	0.49	115	0.059	0.78
3	1618	91	0.056	0.32	104	0.064	0.49
4	1411	82	0.058	0.85	95	0.067	0.91
5	1173	74	0.063	0.91	86	0.073	0.59
6	1064	67	0.063	0.15	77	0.072	0.10
7	867	56	0.065	0.24	64	0.074	0.19
8	663	43	0.065	0.04	50	0.075	0.02
9	565	36	0.064	0.17	41	0.073	0.07
10	370	21	0.057	0.46	23	0.062	0.29
11	252	16	0.063	0.30	17	0.067	0.24
12	81	4	0.049	0.65	4	0.049	0.65

#: Negative values for bulk tank milk test dates occurring before the outcome interval.

Abbreviations: S/P: sample-to-positive ratio in Coxiella burnetii bulk tank milk antibody ELISA.