Herd-level Coxiella burnetii seroprevalence was not associated with herd-level breeding performance in Czech dairy herds.

Q fever was studied on a large agricultural farm in northern Moravia, Czech Republic. Antibodies to Coxiella burnetii were ascertained by a complement fixation test. Titre of 8 or higher was considered as positive. The seroprevalences in cows (each cow was examined only once immediately after drying-off during a one-year period) from 14 different herds was between 4 to 19%. No significant correlation between seroprevalence levels and fertility characteristics in the cow herds was found. Of a total of 17 samples of milk from 17 randomly-selected cows with antibody titres of 8 to 32, one strain of Coxiella burnetii was isolated. In heifers (n = 339) and beef bulls (n = 210) no antibodies to C. burnetii were found. In cattle from the farm investigated, latent Q fever did not represent any health problem.