Bovine leptospirosis: infection by the Hebdomadis serogroup and abortion-A herd study.

A possible relationship is demonstrated between infection of cattle by the Hebdomadis serogroup of Leptospira and abortion of undiagnosed aetiology. This association is based on (1) The occurrence of a much higher incidence of antibodies to serotype sejroe in herds with a history of undiagnosed abortion than in other groups of cattle tested. (2) A relationship between the incidence of cows with antibody titres to sejroe and the incidence of abortion of unknown aetiology in 29 herds during an 18 month model period.