الفهرس 
Introduction and aim of workOnly 14 pages are availabe for public view
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Abstract
In this investigation fiVe immunization programmes for infectious bronchitis virus (IBV) in Egypt were evaluated for their protection ability :
Experimental vaccination programLes compfise a group of birds ;
Group (A) :
Receive one dose of H120 drinking water vaccine at ten days .
Group (B) :
Give two doses of the H120 D.W. at 10 days and 12 weeks .
Group (C)
Received 3 doses of H120 D.W. at 10 days, 12 weeks and 18 weeks .
Group (D)
Birds vaccinated on growing period with H120 D.ir. at 10 days and 12 weeks the third dose of vaccine with oil emulsion vaccine Mass type at 18 weeks . Group (E)
Receive three doses of vaccine the first two doses at 10 days and 12 weeks with H120 via D.., the third dose with oil emulsion vaccine Lass type with variant (IBH—K) D274 & D1466 . Three weeks after vacci-
nation all vaccinated and controls were challenge intra-tracheally withH52 with 0.1 103.5 /per bird . Protection was assessed on respiratory symptoms on challenge during the observation period .
Blood samples from each group were taken before and after vaccination and also after challenge and sera were subjected to HI test .
Results obtained under expermintal condition mentioned before showed that :
1 — The maternal antibodies were high at ten days while their balues began to decrease at three weeks old .
2 — This maternal antibodies did not influence either the vaccination sucess or the serologic response of birds .
3 — Vaccination success in experimental trial using one Or two or three doses of H120 at different ages provoked challengable protection . 4 — The use of dead vaccines either ND/IB or (IBH - K)
primed by two doses of H120 produced protection 87% and 93.5% respectively while in field trial
three doses of H120 produced comparable protection
when the immune response of birds was measured .