Collection of HI negative serum
Collection of HI positive serum
There may be stored serum that is suitable for this purpose. If not, vaccinate several chickens with I-2 Newcastle disease vaccine. Two weeks after the primary vaccination, give a booster vaccination. Two weeks later, take a serum sample from each chicken and test the HI titre. Collect extra serum from chickens with a titre of 25 or above. The volume of blood collected from each chicken depends on the size of the chicken. Pool all the serum samples with HI titres of 25 or above and test the HI titre of the pooled serum.