Economic and production effects of bovine viral diarrhoea : Insights from dairy systems with and without control

Bovine viral diarrhoea (BVD) is a viral cattle disease that presents in most cattle-raising countries worldwide and is listed by the World Organisation for Animal Health as a notifiable disease. Infection of bovine viral diarrhoea virus (BVDV) negatively effects the production and economic performance of the dairy herds. Many countries and regions developed BVDV control or eradication programmes and are at different stages of BVDV control. Therefore, information required for decision making in these countries is different. The overall objective of this thesis was to determine the effects of BVDV infection on the production and economic performance of dairy herds in order to support decision making in countries with and without a systematic BVDV control programme. A systematic BVDV control programme is identified by three central elements: biosecurity, elimination of PI animals and surveillance, as opposed to control attempts without clear objectives and monitoring to assess progress. The Netherlands and China were studied as countries with and without a systematic BVDV control programme, respectively. This thesis covers methodologies from different scientific disciplines including veterinary epidemiology, economics, bio-economic simulation model. The results of this thesis showed that 1) participating in the BVDV control programme at the final stage did not significantly affect the production and economic performance of the herd; 2) The new introduction of BVDV had a negative, but on average a relatively small, effect on milk production, somatic cell count and calf mortality rate in BVDV-free herds participating in the Dutch BVDV-free programme; 3) The within-herd seroprevalence of BVDV in 3 large commercial dairy herds in North China was very high, ranging between 96.3% and 100.0%; and 4) BVDV introduction in a large-scale Chinese dairy herd caused large production and economic losses