Studies of Coxiella burnettii infections and infections with bacteria of the genus Chlamydia in dairy cattle

Comparative studies on the prevalence of infections caused by Coxiella burn etii (C. burnetii) and Chlamydia were carried out with 592 cattle older tha n 2 years and 234 cattle younger than 2 years. Of these 477 originated from 24 dairy herds with considerable fertility problems (positive herds) and 3 49 from 14 dairy herds without major fertility problems (control herds). Fo r the direct detection of these pathogens in the genitals capture ELISAs we re employed, for the demonstration of antibodies the complement fixation te st (CFT). Direct detection of C. burnetii and Chlamydia single as well as mixed infec tion revealed significant higher values for cattle from positive herds comp ared with those from the control herds. Animals revealing insemination rati os of greater than or equal to2 showed significantly more frequent excretio n of Chlamydia via the genitals and antibodies against C. burnetii than cat tle with an insemination ratio of < 2. Investigations of cows which had had an abortion showed no indications of significantly more frequent C. burnet ii or chlamydial infections. Inseminated but non-pregnant cows excreted sig nificantly more C. burnetii and Chlamydia than pregnant cows. Clinical sign s of endometritis were associated with an enhanced excretion of Chlamydia. Animals younger than 2 years excreted significantly more frequently C. burn etii but not Chlamydia via the genitals than animals older than 2 years. In direct test showed results vice versa.