COMPARATIVE-STUDIES ON EFFICACY OF DIFFERENT VACCINES AGAINST FOWL TYPHOID IN CHICKENS

Studies were conducted to compare the efficacy of live avirulent 9R va ccine, protein extracts and formalin- killed bacterin for the protecti on of chickens against fowl typhoid. Vaccination of birds at 9 weeks o f age using strain 9R with and without Freund's complete adjuvant resu lted in 95 and 100% survivors, but the challenge strain persisted in t he organs of 1 bird each. The use of crude protein extract + adjuvant resulted in 100% survival rate along with total clearance of the chall enge strain of Salmonella gallinarum from all the survivor birds. Addi tion Of Freund's complete adjuvant during primary vaccination resulted in higher antibody titres and survival rate. Killed bacterin without adjuvant gave minimum protection against fowl typhoid.