Table 3.

Logistic Regression Analysis of Potential Risk Factors for the Occurrence of Mastitis in the Study Area

Risk Factors	Categories	No. of Animals Exam.	No. Positive (%)	Univariable			Multivariable
				OR	95% CI	P value	OR	95% CI	p value
District	Toke Kutaye	148	35 (23.65)	1.0	–	–	1.0	–	–
	Dendi	162	45 (27.78)	1.24	0.74–2.07	0.407	1.55	0.68–3.49	0.295
	Cheliya	94	43 (45.74)	2.19	1.56–4.73	0.004	1.68	0.73–3.85	0.224
Age	≤ 4 years	234	41 (17.52)	1.0	–	–	1.0	–	–
	≥ 7 years	103	36 (34.95)	2.53	1.49–4.28	0.001	1.88	0.91–3.91	0.089
	5–6 years	67	46 (68.66)	10.31	5.57–19.10	≤0.001	8.68	3.89–19.38	≤0.001
Stage of lactation	> 7 months (late)	48	9 (18.75)	1.0	–	–	1.0	–	–
	< 3 months (early)	297	92 (30.98)	1.94	0.90–4.18	0.089	3.51	1.29–9.51	0.014
	4–7 months (mid)	59	22 (37.29)	2.58	1.05–6.32	0.039	4.01	1.23–13.12	0.022
Number of parities	≤ 2 calves	119	18 (15.13)	1.0	–	–
	3 to 5 calves	211	52 (24.64))	1.84	1.02–3.31	0.044
	≥ 6 calves	74	53 (71.62)	14.16	6.95–28.86	≤0.001
Type of Housing	Separate pen	52	12 (23.08)	1.0	–	–	1.0	–	–
	Shared barn	352	111 (31.53)	1.53	0.78–3.04	0.219	2.61	1.01–6.74	0.047
Interval of cleaning bedding	Once a week	209	32 (15.31)	1.0	–	–	1.0	–	–
	< once a week	51	10 (19.61)	1.35	0.61–2.96	0.456	1.30	0.45–3.75	0.622
	> a week	144	81 (56.25)	7.11	4.31–11.73	≤0.001	7.96	3.73–17.00	≤0.001
Udder washing	Yes	101	11 (10.89)	1.0	–	–
	No	303	112 (36.96)	4.80	2.46–9.36	≤0.001
Type of floor	Concrete	326	98 (30.06)	1.0	–	–
	Muddy	78	25 (32.05)	1.10	0.65–1.87	0.732
Using towel	No	313	95 (30.35)	1.0	–	–
	Yes	91	28 (30.77)	1.02	0.61–1.69	0.939
Tick infestation	Yes	264	76 (28.79)	1.0	–	–
	No	140	47 (33.57)	1.25	0.80–1.94	0.321
History of the previous mastitis	No	221	21 (9.50)	1.0	–	–	1.0	–	–
	Yes	183	102 (55.74)	11.99	7.02–20.50	≤0.001	9.35	4.92–17.78	≤0.001

Abbreviations: CI, confidence interval; OR, odds ratio; No., number; Exam, examined.