Diagnostic information for mastitis treatments on dairy farms

Antimicrobial usage in Dutch livestock has been reduced tremendously since 2009. Inflammation of the udder (mastitis), however, still contributes the most to antimicrobial usage at dairy farms. At this point in time, the step forward likely is to further optimize antimicrobial treatments, instead of to further reduce antimicrobial usage. One approach might be in using test results to determine mastitis treatment. Therefore, the aim of this thesis was to determine the added value of test results on the mastitis treatment strategy of Dutch dairy farmers. The ultimate goal was to contribute to improved mastitis treatments on dairy farms to enhance prudent antimicrobial use for mastitis. Results show that farmers have a need for adding test results to their mastitis treatment decisions, if such information originates from reliable, on their farm applicable (on-farm) tests. Various on-farm tests were equally able to detect and identify mastitis-causing bacteria within 24 h. This time-to-result was perceived as too long by the farmers and thus a quicker type of test was developed within this research that showed good agreement with the currently most often used test. If test results were used by farmers, mastitis treatments improved as compared to their current treatment strategy. Cure of cows, however, was equal or decreased if test results were used to determine treatment. Apparently, the experience and knowledge of farmers cannot be substituted by a result of the on-farm mastitis test evaluated. Mastitis treatments may be further improved by combining expertise of farmers and test results