Should they stay, or should they go? Relative future risk of bovine tuberculosis for interferon-gamma test-positive cattle left on farms

Table 3 Final Cox-proportional hazards model of time to a subsequent positive skin-test

Covariates	Hazard ratio	P-value	95 % Confidence interval
Exposure (referent: Gamma negative)			Lower	Upper
Gamma positive	2.31	<0.001	1.92	2.79
Herd type (referent: Dairy)
Beef	0.78	0.023	0.63	0.97
DVO region nreferent: Southeast)
North	0.45	0.009	0.25	0.82
Southwest	0.56	0.030	0.33	0.95
Variance component
Theta	2.66	<0.001

ISSN: 1297-9716