Table 5.

Generalized linear mixed model of the association between shedding (detected positive by any test on a given sampling day) and shedding in the days prior from the same heifer. Heifer was included in the model as a random effect

Time-frame	Parameter*	Cases† (n)	OR	95% CI	P	Intra-class correlation
Day -1	n.d.	35	1
	Positive	94	3·308	1·851–5·911	<0·001	0·169
Day -2	n.d.	39	1
	Positive	72	1·252	0·674–2·326	0·474	0·255
Day -3	n.d.	40	1
	Positive	54	1·317	0·674–2·577	0·418	0·214
Day -4	n.d.	33	1
	Positive	36	2·108	0·971–4·579	0·059	0·233

OR, Odds ratio; CI, confidence interval, n.d., not detected as shedding in prior days (reference level).

^*Parameter is based on detection by any test in the days prior to detection.

^†Cases were defined as positive on the sampling day by any test (<1 c.f.u./g).