Research

Managerial and environmental determinants of clinical mastitis in Danish dairy herds

Kenji Sato^{^ 1}, Paul C Bartlett² , Lis Alban³ , Jens F Agger⁴ and Hans Houe⁴

¹Department of Veterinary Sciences, College of Agriculture, University of Wyoming, Laramie, WY, USA

²Department of Large Animal Clinical Science, Michigan State University, East Lansing, MI, USA

³The Danish Meat Association, Vinkelvej 11, DK-8620 Kjellerup, Denmark

⁴Department of Large Animal Sciences, Group of Population Biology, Section for Veterinary Epidemiology, Faculty of Life Sciences, University of Copenhagen, Grønnegårdsvej 8 DK-1870 Frederiksberg C, Denmark

author email corresponding author email^Deceased

Acta Veterinaria Scandinavica 2008, 50:4doi:10.1186/1751-0147-50-4

Published:	7 February 2008

Abstract

Background

Several management and environmental factors are known as contributory causes of clinical mastitis in dairy herd. The study objectives were to describe the structure of herd-specific mastitis management and environmental factors and to assess the relevance of these herd-specific indicators to mastitis incidence rate.

Methods

Disease reports from the Danish Cattle Data Base and a management questionnaire from 2,146 herds in three Danish regions were analyzed to identify and characterize risk factors of clinical mastitis. A total of 94 (18 continuous and 76 discrete) management and production variables were screened in separate bivariate regression models. Variables associated with mastitis incidence rate at a p-value < 0.10 were examined with a factor analysis to assess the construct of data. Separately, a multivariable regression model was used to estimate the association of management variables with herd mastitis rate.

Results

Three latent factors (quality of labor, region of Denmark and claw trimming, and quality of outdoor holding area) were identified from 14 variables. Daily milk production per cow, claw disease, quality of labor and region of Denmark were found to be significantly associated with mastitis incidence rate. A common multiple regression analysis with backward and forward selection procedures indicated there were 9 herd-specific risk factors.

Conclusion

Though risk factors ascertained by farmer-completed surveys explained a small percentage of the among-herd variability in crude herd-specific mastitis rates, the study suggested that farmer attitudes toward mastitis and lameness treatment were important determinants for mastitis incidence rate. Our factor analysis identified one significant latent factor, which was related to labor quality on the farm.