Table 1.

Final logistic regression model of potential risk factors significantly (P < 0.05) associated with ringworm infection in calves

Risk factor	Calves		Prevalence	βa	S.E.(β)	ORb	Relative risk
	Infected	Non-infected	(%)			(95% CI)	(95% CI)
Age
1 month (ref.)	66	97	40.49
4–6 months	358	239	59.97	0.789	0.18	2.201 (1.546–3.133)	1.481 (1.215–1.804)
Breed
Pure breed (ref.)	297	312	48.77
Crossbreed	127	24	84.11	1.715	0.236	5.558 (3.494–8.843)	1.724 (1.549–1.919)
Season
Summer (ref.)	190	100	65.52
Winter	81	69	54	−0.48	0.205	0.617 (0.413–0.923)	0.824 (0.695–0.976)
Spring	83	90	47.98	−0.72	0.196	0.485 (0.331–0.713)	0.732 (0.614–0.873)
Autumn	70	77	47.62	−0.74	0.206	0.478 (0.319–0.716)	0.726 (0.601–0.878)
Area per calf
Overcrowding (1.5 m/calf) (ref.)	194	120	61.78
No overcrowding (6 m/calf)	230	216	51.57	−0.42	0.149	0.659 (0.491–0.884)	0.834 (0.736–0.945)
Ventilation
Good (ref.)	295	315	48.36
Bad	129	21	86	1.88	0.248	6.559 (4.027–10.683)	1.778 (1.602–1.973)
Production system
Milk (ref.)	282	318	47
Meat	142	18	88.75	2.185	0.263	8.896 (5.310–14.902)	1.888 (1.706–2.089)
Breeding system
Semi-intensive (ref.)	305	297	50.66
Intensive	119	39	75.32	1.089	0.202	2.971 (2.001–4.412)	1.486 (1.319–1.674)
Origin of the animals
Born at the farm (ref.)	302	313	49.11
Newly purchased	122	23	84.14	1.704	0.241	5.497 (3.426–8.820)	1.713 (1.539–1.907)
Parasitic infestation
Absent (ref.)	312	278	52.88
Present	112	58	65.88	0.542	0.181	1.720 (1.205–2.456)	1.245 (1.091–1.422)
Use of disinfectant
Irregular (ref.)	125	27	82.24
Regular	299	309	49.18	−1.57	0.227	0.209 (0.133–0.326)	0.598 (0.536–0.667)

^aRegression coefficient

^bOdds ratio