All boars admitted to a semen collection centre must: ... (c) before the period of isolation specified in (a), and within the previous 30 days, have been subjected to the following tests with negative results: ... (ii) a serum neutralization or an ELISA test using all the viral antigens in the case of non-vaccinated pigs, - an ELISA test for G1 antigens in the case of pigs vaccinated with a G1 deleted vaccine.
