Authors : Maria Dolores Fuentes Delgado , Irene V. Vitela Mendoza , Beatriz Arellano-Reynoso , Rigoberto Hernandez Castro , Jose Francisco Morales Alvarez , Carlos Cruz-Vazquez , Francisco Suarez-Guemes and Efren Diaz-Aparicio
Abstract: The present study was aimed to detect B. abortus DNA from aborted cows and differentiated its vaccinal and/or field origin. The PCR technique was used to identify and differentiate S19, RB51and field strains. The research was performed in a dairy farm located in the state of Aguascalientes, Mexico, with reproductive problems and abortions. Cows were vaccinated when calves with RB51, normal dose and revaccinated with RB51reduced dose 8 months before starting the study. The number of revaccinations of each cow, was not known since it is customary to revaccinate in one or more occasions. Samples of milk, blood serum and vaginal exudates were collected from 30 cows that had aborted between day 166 and 260 of gestation, all the abortions occurred 22-30 days before sampling; Card, rivanol and radial immunodiffusion tests were performed for Brucellosis diagnosis. For the bacteriological study samples of milk and vaginal swabs were used. The isolated strains were subjected to PCR using specific primers for RB51, S19 and field strains. From the 30 vaginal exudate samples bacteriological analyzed, we isolated smooth B. abortus biotype 1 was isolated from four cows. Thirteen out of the 30 cows vaginal exudates analyzed by PCR revealed the presence of DNA corresponding to RB51 vaccine, the 13 cows that were positive to RB51 through PCR had negative results in both the bacteriological and serological studies.
Maria Dolores Fuentes Delgado , Irene V. Vitela Mendoza , Beatriz Arellano-Reynoso , Rigoberto Hernandez Castro , Jose Francisco Morales Alvarez , Carlos Cruz-Vazquez , Francisco Suarez-Guemes and Efren Diaz-Aparicio , 2007. Presence of Brucella abortus Vaccinal Strain Rb51 in Vaginal Exudates of Aborted Cows. Research Journal of Dairy Sciences, 1: 13-17.