Vaccinated animals will produce antibodies to the BVD virus. These antibodies are the same as those produced in response to natural infection. Therefore if blood sampling for BVD antibodies, it is not possible to tell if antibodies detected are the result of vaccination or infection with BVD virus. If performing a youngstock screen, it is recommended to blood sample cattle between 9 – 18 months of age, before they are vaccinated.
Tag and Test is based on testing for BVD Virus. Vaccination has no effect on the presence of virus in PI animals and thus they will still test positive after vaccination. Therefore vaccination does not affect these results.