EN
The aim of the study was to determine the etiological factors of an outbreak of cattle illness with symptoms nervous disorders. The disease appeared simultaneously in adult animals on three dairy farms between August and October. The majority of sick animals was after parturition and had high milk production. The diagnosis gene was found through clinical anatomopathology, histopathology and bacteriological examinations of the animals, as well as molecular, serological, virusological and chemical tests. L. monocytogenes was isolated from the brain tissue of the dead animals. Restriction analysis (PCR-RFLP) of the DNA fragment of the hly A gene from L. monocytogenes facilitated differentiation between the virulent and control strains. It was found that the copper and selenium levels in the cows' serum were reduced significantly. Additional examinations indicated the low content of these minerals in the forage.