Questionnaire-based study to assess the association between management practices and mastitis within tie-stall and free-stall dairy housing systems in Switzerland

Table 3 Final multivariable negative binomial regression model between management practices and clinical mastitis (incidence rate ratios (IRR) and 95% confidence intervals (CI)) from 204 Swiss dairy farms with a free-stall and >10 cows in 2010

Factor	Category	IRR (95% CI)	P-value
Milk yield	High (> 6,122 kg)	1.25 (1.03-1.52)	0.01
Milk yield	Low (≤ 6,122 kg)	1.0	-
Somatic cell count controls	At longer intervals	1.44 (1.13-1.84)	0.003
Somatic cell count controls	≤2 times/month	1.0	-
Bacteriological test carried out for clinical mastitis	Never	0.61 (0.42-0.88)	0.01
Bacteriological test carried out for clinical mastitis	Always/occasionally	1.0	-
Dry cow udder controls during the dry period	Yes	0.67 (0.54-0.83)	<0.001
Dry cow udder controls during the dry period	No	1.0	-
Teat cleaning material	Washable towel	1.53 (1.04-2.25)	0.02
Teat cleaning material	Other†	1.0	-
Body condition scoring	No	0.74 (0.62-0.90)	0.002
Body condition scoring	Yes	1.0	-
Important characteristic when selecting a bull for artificial insemination	Total merit values	1.57 (1.17-2.11)	0.002
	Other‡	1.0	-
Clean bedding material at calving	Yes	1.72 (1.24-2.38)	0.001
Clean bedding material at calving	No	1.0	-
Hands and arms are cleaned if intervention is required at calving	Yes	0.75 (0.61-0.93)	0.009
	No	1.0	-
Ropes or chains available at calving if required	Yes	1.37 (1.08-1.75)	0.009
Ropes or chains available at calving if required	No	1.0	-

^†Paper towel, wood wool, wet towels with disinfectant, wet towels without disinfectant, no material.
^‡Milk yield, fat and protein content of milk, somatic cell count in milk, exterior, ease of calving, length of productive life, milking speed/persistence of lactation, fertility of the dam, beef production.

ISSN: 1746-6148