Key elements of IBR eradication

IBR eradication programs are based on vaccination of cattle, controlled movement of cattle, biosecurity and monitoring of herds.

Vaccination against BoHV-1

Herds with a high sero-prevalence of BoHV-1 opt for eradication with vaccination. The vaccine is administered bi-annually usually in spring and autumn. There are currently live and inactivated vaccines available. For more information on the use of vaccines and timing of vaccination see IBR marker vaccines.

Movement of cattle

Other measures are also be implemented to reduce the possibility of BoHV-1 virus entering a herd. Strict measures are applied when purchasing animals. Only cattle of a similar or higher IBR Health status should be introduced into the herd. Quarantine facilities should be available. Animals should be in quarantine until they are cleared as fit to be introduced into the herd.

Biosecurity

Biosecurity measures should be in place in order to avoid mechanical transmission of the virus.
Read more under Control - biosecurity.

Monitoring

1. During IBR eradication

   In order to assess the progress of BoHV-1 eradication in a herd certain age groups should be sampled.
   Two years after starting the vaccination program samples can be collected from animals between 6 to 24 months of age. This would include calves which are already free of maternally derived antibodies and heifers that are not pregnant or pregnant with their first calf. A negative result in this group of animals indicates that there has been no virus circulation amongst the group.

   In subsequent years monitoring would target the same age group (6-24 months) and can follow up those animals that were included in the first selected group.

   In dairy herds bulk milk testing can be used to monitor gE sero-prevalence in the milking herd. The ELISA gE testing in bulk milk is not very sensitive, however it is estimated that negative results are seen when less than 10% of the cows contributing to the milk sample are gE positive. This is a simple and inexpensive way to monitor BoHV-1 sero-prevalence in the group.

2. Once a herd is certified BoHV-1 free

   Once a farm is certified to be free of BoHV-1 it is important to establish a system to monitor if there has been a new introduction of BoHV-1 in the herd. Monitoring of BoHV-1 free status varies between countries:

   • The Netherlands - a bulk milk sample is tested almost monthly.
   • Belgium - individual blood samples are collected twice a year.
   • France - bulk milk samples or pool blood samples are tested twice a year.
   • Germany - either bulk milk testing or individual blood sampling is carried out every 6-12 months depending on the province.