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Objective: Evaluation the serological reactions against RevI vaccine and the effects of different ages of vaccination on titers. Design: Comparative study. Animals: One hundred and eighty six lambs, which had received one dose of RevI vaccine, underwent on this study.
Procedure: To be sure that all animals were free from brucellosis
they were checked with RBPT before vaccination. All animals were tested with RBPT, Wright and 2ME. These lambs divided to 8 ages - group with one-month interval differences from 4 to 11 months old. Statistical analysis: Linear regression analysis. Results: After vaccination only 6 lambs were positive by RBPT
up to 42 weeks post vaccination. Wright’s titers dropped to zero as
bellow: in 4 months old group aftcrl4 weeks; in 5, 6 and II months
old after 30 weeks; in 10 months old after 36 weeks, and in 9
months old after 42 weeks. In 42nd week mean titer of the 7 and 8-months-old group were respectively 1.85 and 6.15. 2ME titer dropped to zero as fallow:
in 4 and 5 months old group after 14 weeks; in 11 month old after 18 weeks; in 6 month old after 24 weeks; and other groups after 42 weeks. Conclusion: According to the results the 4 months old group had
the sharpest decreasing titer in cantrast to the 7, 8 and 9 months
old group that had been slowest ones. Significant differences in the titer between group of 4 and 8 months old, especially in the were found last weeks of titration. Moreover in 7 and 8 months old group
the titers lasted relatively for a longer time than the others. In conclusion, age of vaccination against Rev I had considerable effects
on serological titers. J. Fac. Vet. Med. Univ. Tehran. 57,2: 89-93,