We have described 5 abortion outbreaks in Bos grunniens Linnaeus from Aba in 1979~1982.The prevalent rate is 22.6%,58.16%,47.10% of sero detected in the abortionwere considered pesitive,but positive sero in control herds were only 17.39%.This result shown a sttistically sinificant in both subject and control groups.11herdsstrains of Br.abortus biotype 9 were isolated from abortus collected during thatperied,the rate was 61.11%.It demonstrated that abortion of Bos grunniensLinnaeus.caused by Br.abortus bioty...