Abstract
This study evaluated Boschveld chicken's antibody response to a standard Newcastle Disease (ND) vaccination program designed for the Hyline Brown chickens. Both breeds were challenged with the LaSota vaccine at days 1, 69, 111, and 195. The blood samples were aseptically collected from 10 randomly selected birds per breed on each vaccination day (1, 69, 111, and 195) and 10 days after each vaccination (10 dpi). The sera were tested for anti-ND virus (NDV) antibodies using the Haemagglutination inhibition (HI) assay. The anti-NDV antibody titers were expressed in log 2 as geometric mean ± standard deviation. Before any vaccination, 80% of Boschveld chicken sera tested negative for anti-ND virus antibodies, significantly higher than that of Hyline Brown chickens (40%). Hyline Brown day-old chicks had a higher antibody titer (4.95 ± 0.21) than Boschveld day-old chicks (3.21 ± 0.43) before vaccination. The Boschveld accumulated higher antibody titers (13.98) than the Hyline Brown breed (13.85), despite the Boschveld having lower antibody titers at day 1. The antibody titers of the Boschveld did not change significantly (p > 0.05) after the 4th vaccination dose. For effective immune control of ND, the vaccination program for commercial layer chickens can be optimized to suit the Boschveld chickens by reducing the frequency of booster vaccinations. The 4th ND vaccination must be delayed until antibody titers approach the minimum protective threshold. This intervention can also be adopted for Boschveld chicken's close relatives, such as village (native) chickens.
