Table 1.

Temporal antibody profile (TAP) criteria and distributions of animals, observations, faecal culture-positive observations and age in 14 dairy herds that were endemically infected with S. Dublin in Denmark between 2000 and 2002

Group and short explanation	Criteria	No. of animals*	n (%) observations	n (%) faecal culture-positive observations†	Average age, years (95% CI)
TAP1: Persistently high antibody levels	The current and the previous two samples ≥80 ODC%	126	182 (2·8%)	3 (1·7%)	3·8 (3·6–4·1)
TAP2: Recent increase in antibody levels	The current sample ≥50 ODC% and the previous one or two  samples <25 ODC%	214	214 (3·2%)	6 (2·8%)	2·7 (2·4–2·9)
TAP3: Fluctuating or moderately  high antibodies	One of the previous samples ≥25 ODC%, but not three  samples ≥80 ODC%	1696	4022 (61%)	31 (0·8%)	3·4 (3·3–3·4)
TAP4: Recent low antibody levels	The current and the previous one or two samples <25 ODC%	1061	2196 (33%)	6 (0·3%)	2·9 (2·8–3·0)

CI, Confidence interval; ODC%, background-corrected optical density value.

The TAPs were based on the two or three most recent samples from each animal aged ≥180 days. The TAP groups were mutually exclusive.

^*Number of animals represented in the number of observations.

^†Percentage of the sample event observations in which S. Dublin bacteria were isolated.