1-
The immunizing power of three blackleg vaccines (alum precipitated vaccine, aluminium gel with saponin adsorbed vaccine and oil adjuvant vaccine) was tested in guinea-pigs. The oil adjuvant vaccine had the highest power of protection
10 days after immunization with one dose of the vaccine. Twenty one days after immunization, the three vaccines were equal in their power of protection. Studies on the immune level of vaccinated guinea-pigs showed that the agglutination titre obtained from testing individual guinea-pig sera was parallel with protective immunity against challenge with Cl.chauvoei spore suspension.
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3- Studies on the immune response of the three blackleg vaccine
was investigated in sheep and buffaloes using agglutination test showed that the oil adjuvant vaccine gave the best and most rapid response. In sheep also vaccinated with a single dose of oil adjuvant vaccine retained a high agglu tination until the end of one year, but in cattle and buffa loes the titre was satisfactory up to 9 month for the
same vaccine. 4- An agglutination titre of 0.5 uL of sheepserum or less
required to agglutinate Cl.chauvoei standardized antigen indicated full protection against challenge.