2) Supplements of 32th Congress of Veterinary Epidemiology
The Factor Associated with Occurrence of Mastitis Caused by Staphylococcus Aureus
2011 Volume 16 Issue 1 Pages 15-16
Details
2011 Volume 16 Issue 1 Pages 15-16
Mastitis is a very important disease in dairy farming. In Okhotsk, Japan, Staphylococcus aureus (SA) mastitis incidence increased after the introduction of anonymous post-dipping Iodine-based product A. The purpose of this study was to examine the association between the product A and the disease increased.
The dairy cows monitoring data for 5 farms using product A and 4 farms using another anonymous Iodine-based product B in the dairy farms which belong to Okhotsk Farmers’ Association and encountered with SA mastitis incidence were used for this analysis. In univariate analyses, farming style (tie or free stall), pre-milking teat disinfectant (2 products) and post-dipping products were selected as explanatory variables and the incidence of SA mastitis on each teat between 2005 April and 2007 March was selected as a response variable. Generalized Linear Models (GLMs) with Poisson errors were employed for these analyses. In multivariable analysis, as the incidence of SA mastitis on each teat could be affected by the intra-class correlation at two levels:animal and farm levels, robust variance using Generalized Estimating Equations (GEE) was performed in statistical software R version 2.13.1. The explanatory variables with the p-values less than 0.2 in the univariate analyses were selected for GEE and step-wise model simplification was performed.
In univariate analysis, there was no significant difference in mean SA mastitis annual incidence per teat between tie (0.025) and free stall (0.028, p=0.53) or between two pre-milking disinfectant products (0.022 and 0.029, p=0.08). However, the mean annual incidence was significantly higher in teats which post-dipping product A was used (0.035) than those which product B was used (0.015, p<0.001). In multivariable analysis, only the use of post-dipping product A was significantly associated with the annual incidence (p<0.001).
In the present study, only the post-dipping product was associated with the SA mastitis incidence among farming style, pre-milking disinfectant and post dipping products. Change of post-dipping product and economic evaluation after the intervention would be recommended to the farms with increased incidence.
