Abstract

The study was designed to investigate the presence and level of maternally derived antibodies (MDA) in broiler and pullet chicks to determine the right days and time of vaccination against Infectious bursal disease (IBD). A total of 150 day old broiler chicks and pullets chicks were obtained from reputable breeder farmers and the birds divided into 5 groups (A, B, C, D and E) comprising 30 chicks per group. Coefficient of variation (CV), central vaccination time (CVT), and vaccination days (VD) from mean MDA (passive immunity chicks derived from parents’ stock) ELISA titres were also determined using Hipra calculator (a device online for determining vaccination day and time from mean ELISA titers). One milliliter of blood sample was collected from each broiler and pullet chick from all the groups to obtain sera. The antibody titre level of broiler chicks ranged from 1,962 ± 438 to 4,363 ± 974 while that of pullets ranged from 2,111 ± 471 to 4,526 ± 1011. The highest CV was 46% for broiler chicks from farm A and the highest CV for pullets was 42.5% from another breeder farm D. The CVT for broilers to be vaccinated with mild IBD vaccine was 19 days, it was 18 days for intermediate vaccine and for intermediate plus vaccines was 12 days. The CVT was 33 days for pullets to be vaccinated with mild vaccine, 31 days for intermediate vaccine, while with intermediate plus vaccines it was 20 days. While the vaccination days for broiler was 7 and 17 days and it was 10 and 25 days for pullets. From the study the presence and level of MDA in day old chicks has been established and was above 1000 ELISA titre in chicks from all the five breeder farms.

Key words: Broilers, ELISA, Infectious bursal disease, Maternal derived antibodies, Pullets