A field study on the significance of vaccination against infectious bursal disease virus (IBDV) at the optimal time point in broiler flocks with maternally derived IBDV antibodies

Abstract

The right strategy for infectious bursal disease (IBD) control and its success rate under field conditions depends on hygiene management, IBD field pressure, level and variation in maternally derived IBD antibodies, and the IBD vaccine strains to be used. Usually, standard vaccination programmes are used, which are not always adapted to the specific conditions on the farm and to the immune status of chickens. Employing the ''Deventer formula'' may help to estimate the optimal time for vaccination for a specific flock based on the maternally derived antibody level, its variation, the genetic background of the chicken, and the IBD vaccine strain. Two field studies with 16 or 20 commercial broiler flocks were conducted, applying an intermediate IBD vaccine before, at the best, and after the estimated optimal vaccination time estimated by the ''Deventer formula''. These studies showed that flocks IBD-vaccinated between 1 day before, at, or up to 3 days after the estimated optimal time point developed detectable humoral immunity up to 14 days post vaccination. If birds had been vaccinated more than 1 day before the calculated optimal vaccination date, the humoral immune response was delayed or non-detectable until slaughter. The induction of humoral immunity correlated with the incidence of bursa lesions and IBDV detection by reverse transcriptase-polymerase chain reaction. As indicated in this study, under field conditions bursa lesions may develop later than predicted based on experimental experiences. The late incidence of bursa lesions after vaccination may be confused with field virus-induced lesions, in which case sequencing may offer a valuable tool for differentiation.

Ecological and life-history factors influencing the evolution of maternal antibody allocation: a phylogenetic comparison

“…As such, the benefits of maternal antibodies could be of greater importance, while the potential developmental costs are diminished, for these species. The idea that maternally derived antibodies have a blocking effect on offspring immunity has been important for the development of vaccination schedules in human and veterinary medicine (Block et al 2007;Siegrist 2007). Although the effect of maternal antibodies on immune responses is well documented, it is not clear whether this blocking effect is exclusive to T-cellmediated responses or whether it might also affect lymphocyte development (Carlier & Truyens 1995).…”

Evaluation of the Protection against Infectious Bursal Disease (IBD) Challenge in Progeny Born to Parents Having Received a Vaccination Program Using a Herpesvirus of Turkey-Infectious Bursal Disease (HVT-IBD) Vector Vaccine

“…Vaccination strategy is dual: passive protection induced by the maternally-derived antibodies (MDA) and active immunization of the progeny by its vaccination [2,3], taking into account the interference between these MDAs and the live vaccine take. A very virulent form of the disease was described around twenty years ago [4,5] and is still considered as a major treat to the poultry industry everywhere in the world [6], and more recently in the United States of America [7].…”

Practical aspects of estimation of optimal time for vaccination of chicken against IBD with use of „Deventer formula”

“…Block et al (2007) demonstrated that vaccination against IBD 24 hours before or 3 days after the estimated optimal time for vaccination resulted in a satisfactory serological response (14 days post vaccination) in evaluated chicken flocks. In the field "500" vaccines are most often given to birds on the 16 th day of life, as a routine, in cases where Deventer formula is not implemented.…”

“…The layout of estimated optimal days for vaccination of broiler chickens against IBD in regard to the sampling age is summarized in table 2. In the light of the results of Block et al (2007), our findings indicate that the 16 th day vaccination routine would result in satisfactory vaccine-induced immunity in 79.01 and 54.71% of the analyzed cases where birds were still protected by the MDA (in regard to vaccinal MDA break-through; 16-17 th day of life) and in 98.76 and 100% of the cases in general (13-17 th day of life) if blood samples were collected 0-3 or 4-7 days after hatch respectively. The above data indicate that the accommodation period and other factors interfering with yolk sac resorption influence the outcome of chicken anti -IBD serum MDA level, which may affect vaccination schedule and efficiency.…”

“…The basic assumption of "Deventer formula" is that serological examination of chicken poults enables determination of the optimal day for vaccination of chickens against IBD with the use of known MDA half-life (de Wit 2001). Recent studies demonstrated the significance of Deventer formula use in vaccination strategy against IBD (Block et al 2007). …”