Table 5. Odds Ratios (ORs) and 95% credible intervals (in parentheses) of recurrence for the nuisance variables in the recurrent breakdown analyses.

Follow-up	Breakdown history	Max. herd size	Total no. of reactors
12 months	1.5 (1.3–1.7)	1 (0.97–1.1)	1.1 (1.1–1.2)
24 months	1.4 (1.2–1.6)	1 (0.93–1.1)	1.1 (1.1–1.2)
36 months	1.5 (1.3–1.8)	1 (0.97–1.1)	1.1 (1.1–1.2)

The OR for breakdown history is defined relative to having no breakdowns in the previous three years; the OR for the maximum herd size is per unit log-increase in herd size, and likewise for the total number of reactors. Models are fitted to each follow-up period (12, 24 and 36 months) separately.