©FUNPEC-RP www.funpecrp.com.br Genetics and Molecular Research 19 (3): gmr18659 C. Mantovani et al. 2 explain this positivity before vaccination is that the already vaccinated mothers could have transmitted the vaccine to the calves, as the cows presented excretion of the S19 strain in milk and/or urine. This is the first report of the finding of this bovine brucellosis vaccine strain in the blood of calves before vaccination.