In this project, socio-economic and epidemiological aspects of hormonal use for reproductive diseases in Dutch dairy farms will be investigated. First, the association between hormonal use for reproductive diseases and reproductive performance will be investigated to identify the effectiveness of the use. Secondly, the mindset of dairy farmers towards hormonal usage for reproductive diseases will be determined through a knowledge, attitude and practices study. Thirdly, a bio-economic simulation model will be developed to compare technical and economical outcomes of different hormone use strategies for reproductive diseases. Finally, the new Dutch veterinary hormonal use guideline published in autumn 2021 will be evaluated to determine the possible effects of changes on hormone use and reproductive performance. The results will provide baseline epidemiological and socio-economic information for the evaluation and standardization of hormone use in dairy farms, which can be used by farmers, veterinarians and other decision makers to start optimizing hormone use.