This thesis studies the economic impact of bovine viral diarrhoea virus (BVDV) infection on Dutch and Chinese dairy herds using empirical and bio-economic simulation models. The results showed that (re)introduction of BVDV has a very small effect on the performance of Dutch dairy herds participating in the BVDV-free program while having significant negative effects on Chinese dairy herds without control measures, revealing the effectiveness and importance of the control program