Dutch bovine viral diarrhea virus control program: Evaluation 2018-2023.

Since 2018, Dutch dairy farmers have been obliged to opt for 1 of 4 routes to achieve bovine viral diarrhea virus (BVDV) freedom in the national BVDV eradication program. This observational study evaluated efficacy of the total BVDV program using indicators such as the number of persistently infected (PI) cattle, the percentage of dairy herds with a BVDV-free status, and the percentage of BVDV-free dairy herds with evidence of introduction of BVDV, as well as a cost calculation per route. The Dutch BVDV program appeared to be successful, as the percentage of BVDV-free dairy herds increased from 59% at the start of the program to 89% by the end of 2023. The number of PI detected each quarter declined from 500 PI in the third quarter of 2019 to 83 PI in the last quarter of 2023. The percentage BVDV-free dairy herds with evidence of (re)introduction of BVDV decreased from 1.29% per quarter in the first year of the mandatory program to 0.25% per quarter by the end of 2023. In Europe, BVDV control program designs are often tailored to the country's specific situation, such as the prevalence at the start of eradication, risk profile of a country or herd, desired speed of eradication, and available funds. These results show that the Dutch approach, in which multiple routes can be followed toward BVDV freedom, is successful.