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

Table 2 Final multivariable negative binomial regression model between management practices and clinical mastitis (incidence rate ratios (IRR) and 95% confidence intervals (CI)) from 432 Swiss dairy farms with a tie-stall and >10 cows in 2010

Factor	Category	IRR (95% CI)	P-value
Farmers age	>45	0.81 (0.71-0.93)	0.003
Farmers age	≤45	1.0	-
Production zone	Mountain	0.73 (0.62-0.85)	<0.001
	Hill	0.91 (0.75-1.09)	0.32
	Valley	1.0	-
Dairy herd replacement system	Buying cows	1.27 (1.08-1.50)	0.004
Dairy herd replacement system	Other†	1.0	-
Prophylactic measures taken when purchasing a dairy cow	Never purchase	0.83 (0.71-0.98)	0.02
Prophylactic measures taken when purchasing a dairy cow	Other‡	1.0	-
Milking system	Bucket	1.21 (1.04-1.41)	0.01
Milking system	Pipeline	1.0	-
Teat cleaning material	Paper towel	1.19 (1.04-1.37)	0.01
Teat cleaning material	Other§	1.0	-
Feeding system	Cow specific	0.81 (0.66-0.99)	0.04
Feeding system	Other^¶	1.0	-
Intervention at each calving	No	0.87 (0.75-0.99)	0.04
Intervention at each calving	Yes	1.0	-

^†Buying heifers, own rearing, contract rearing.
^‡California Mastitis Test, milk samples taken for bacteriological culturing, somatic cell count data from breeding associations is checked, claw condition is checked.
^§Wood wool, washable towel, wet towels with disinfectant, wet towels without disinfectant, no material.
^¶The same for all cows, different for lactating and dry cows, different for different production groups.

ISSN: 1746-6148