No abstract

The study was carried out to evaluate the vaccination programmes with Nobilis® Gumboro D78 (Intervet, Netherland) against Gumboro disease with persistance of maternally derived antibody in broiler chickens during two month period from August to September 2003 in Sherpur district of Bangladesh. A total of seven farms were selected, of which owners of five farms practiced their own vaccination programme i.e., primary vaccination at 5 (three farms), 7 and 8 days old with no booster against infections bursal disease (IBD) whereas imposed vaccination schedule (primary vaccination at 14 days old with a booster at 28 days old) was implemented in the remaining two farms. The vaccination programmes were evaluated by determining the antibody titres before and after vaccination and by morbidity and mortality of the vaccinated chickens against Gumboro disease. The present investigation demonstrated that mortality of chickens occurred in farms in which the birds were vaccinated between 5 to 7 days of age. The present result revealed that 7 days after primary vaccination the titer level decreased significantly (p < 0.05) in all the farms in which the farmers followed their own vaccination schedule. The present result also demonstrated that the mean titer before primary vaccination was 1276.8 ± 43.84 but seven days after vaccination it increased (1434.2 ± 29.97) insignificantly (p > 0.05) and this increasing rend continued up to 14 days after vaccination that is upto the age of 28 days (1549.6 ± 33.38) and seven days after booster dose that is at the age of day 35 the mean titer increased (2886.60 ± 80.67) significantly (p < 0.05) in the remaining two farms where the imposed vaccination programme was implemented. The present results obviously demonstrated that maternal antibody level decreasing about half within five days and decreased to negative level (364.00 ± 9.25) by the day 20. From the present study it may be concluded that broiler birds may primarily be vaccinated at the age of around day 14 with a booster at 28 days old.