Investigation on Shedding of Vaccinal Strain in Milk after Inoculation of Rb51 Full Dose Vaccine in Milking Cows

The main purpose of this study is to evaluate the RB51 Brucella abortus vaccine for immunization of mature and pregnant cattle against the brucellosis and shedding of vaccine strain after inoculation of RB51. Full dose vaccine contains 10 - 34×109 CB particles in milking cows. 43 cattle were selected that in the background of the heard, brucellosis diseases was recorded. The cattle were vaccinated against brucellosis by above mentioned dose of vaccine. 11 head out of 40 milking cows were pregnant between 2 - 6 month. All the cattle were proved negative (Unless 3 cows) in the serological tests and milk samples cultured in special culture media before vaccination. The positive cattle were slaughtered. All of the selected cattle received 10-34 × 10 9 (c. f. u) particles subcutaneously. The vaccinated cows had permanently surveyed and any effects followed by vaccination were recorded. Water consumption and swelling were normal and any changes didn't observe in the output rates of milking in cows. The pregnant cows had the normal situation and abortion didn't occur. Milk samples were taken weekly during the study and microbiological tests culture were executed in order to finding the shedding of vaccine strain. All the results were proven negative up to 8 weeks. In conclusion, not only undesirable side effects due to inoculation of RB51 strain vaccine were recorded, but no shedding of bacteria was proven.