Response of Bali cattle (Bos javanicus) to vaccination with Brucella abortus strain 19 in West Timor

A trial was conducted in two villages (one containing cattle infected with brucellosis and one not containing infected cattle) in Timor, Indonesia to determine the serological response to vaccination with Brucella abortus strain 19 in Bali cattle (Bos javanicus) (n = 599). Mature female cattle were immunised with low-dose strain 19 (2x10(8)-6x10(8) colony forming units) and calves (6-12 months) with high-dose strain 19 (4x10(10)-12x10(10) colony forming units). Other mature females and calves were inoculated with sterile vaccine diluent and formed a non-vaccinated in-contact control group. The seroprevalence and mean titres were highest in the vaccinated cattle 3 months after vaccination. These then receded, however, 1% of vaccinated calves and 1.9% of vaccinated cows from the village without infected cattle were still seropositive on the complement-fixation test (CFT) 24 months after vaccination. Non-vaccinated seropositive animals were more likely to have aborted or had a stillbirth and were less likely to have produced a calf than were seronegative cows from the village containing infected animals. We concluded that strain 19 vaccine induced protection in Bali cattle and that this vaccine might play an important role in the control of bovine brucellosis in Timor.