International Journal of Poultry Science1682-83561994-7992Asian Network for Scientific Information10.3923/ijps.2012.138.142BoudaoudA. MamacheB. 22012112Collecting sera from new-born chicks requires their sacrifice, which is an invasive and little economic method of sampling. We studied the possibility of replacing the antibody titres in serum of chicks by those in pre-incubated egg yolk for determining the optimal Age of Vaccination (OAV) against Infectious Bursal Disease (IBD) by the Deventer formula. The study focused on 10 hyper-immunized broiler-breeder flocks. Yolk of pre-incubated eggs and sera of newborn chicks, originated from the same parent flock, were essayed by Enzyme-Linked Immunosorbent Assay (ELISA) to detect IBDV specific Maternally Derived Antibodies (MDA). ELISA titres in both types of samples were similar (p<0.05) and well correlated (r = 0.74, p<0.05). The difference between the two vaccination age estimations, based on egg yolk and serum antibodies respectively, was minimal (less than one day). This difference was independent of parent breeder-flock age (r = 0.04, p>0.05 NS). These results encourage the use of egg yolk in predicting the OAV against IBD instead of sera from sacrificed chicks.]]>Al-Natour, M.Q., L.A. Ward, Y.M. Saif, B. Stewart-Brown and L.D. Keck,200448177182Block, H., K. Meyer-Block, D.E. Rebeski, H. Scharr, S. de Wit, K. Rohn and S. Rautenschlein,200736401409Brown, J., R.S. Resurreccion, T.G. Dickson and A. Horne,198933654656Brown, M.B., M.L. Stoll and G.D. Butcher,19912929012903 De-Wit, J.J.,20012001pp: 171 178De Wit, J.J., J.F. Heijmans, D.R. Mekkes and A.A.W.M. van Loon,200130543549Gagic, M., C.A. St Hill and J.M. Sharma,1999In ovo vaccination of specific-pathogen-free chickens with vaccines containing multiple agents.]]>43293301Goutebroze, S., M. Curet, M.L. Jay, C. Roux and F.X. Le Gros,200344824825Haddad, E.E., C.E. Whitfill, A.P. Avakian, C.A. Ricks, P.D. Andrews, J.A. Thoma and P.S. Wakenell,199741882889Jeong, O.M., M.C. Kim, H.M. Kang, G.W. Ha and J.S. Oh et al.,2010144287292Jeurissen, S.H., E.M. Janse, P.R. Lehrbach, E.E. Haddad, A. Avakian and C.E. Whitfil,199895494500Jungback, C. and H. Finkler,199686157163Keck, L.D., J.K. Skeeles and R.W. McNew,199337825828Lukert, P.D. and S.M. Saif,20032003pp: 161-180pp: 161-180Mohammed, H.O., R. Yamamoto, T.E. Carpenter and H.B. Ortmayer,1986Mycoplasma gallisepticum and M. synoviae antibodies by enzyme-linked immunosorbent assay.]]>30398408Rauber, R.H., M.L. Flores, C.E. Pereira and M. Grigulo,20046117119Rose, M.E., E. Orlans and N. Buttress,19744521523Silim, A. and D. Venne,19893643648Tressler, R.L. and T.F. Roth,19872621540615412Van den Berg, T.P.,200029175194Van den Berg, T.P. and G. Meulemans,199120409421West Jr., A.P., A.B. Herr and P.J. Bjorkman,200420601610