Table 2.

Univariate and multivariate analyses of the animal-level prevalence of C. burnetii in cattle

Risk factors	Prevalence % (n seropositive/total)	Univariate analysis OR (95% CI)	Best fitting multivariate model OR (95% CI)
Age (months)
<37	6.53 (38/582)	ref	ref
37–66	8.82 (47/533)	1.38 (0.89–2.16)	1.42 (0.91–2.22)
67–107	15.98 (85/532)	2.72 (1.82–4.07)**	2.79 (1.86–4.18)**
>107	12.38 (67/541)	2.02 (1.33–3.07)**	2.07 (1.36–3.14)**
Sex
M	5.19 (8/154)	ref	–
F	11.18 (230/2057)	2.28 (1.11–4.71)*
Breed
MRN	7.27 (25/344)	ref	ref
MB	11.62 (143/1232)	1.68 (1.08–2.61)*	1.74 (1.11–2.72)*
CHL	10.67 (19/178)	1.52 (0.82–2.85)	1.61 (0.86–3.03)
Other	11.49 (50/435)	1.66 (1.00–2.74)	1.76 (1.06–2.92)*
Herd size
<30	9.39 (49/522)	ref	–
30–46	11.52 (104/903)	1.26 (0.88–1.80)
47–92	9.59 (23/240)	1.02 (0.61–1.72)
>92	11.38 (62/545)	0.24 (0.83–1.84)
Animal species
Cattle	10.58 (187/1768)	ref	–
Cattle + sheep	2.88 (51/442)	1.10 (0.79–1.53)
Total cattle (n)	2210

OR, odds ratio; CI, confidence interval; ref, reference category.

*P < 0.05; **P < 0.01.