[Experimental udder infection with Escherichia coli. 1. The behavior of selected clinical, hematological and other parameters concerned with milk composition].

Four cows with clinically intact udders in high lactation were intracisternally infected by a pathogenic field strain of Escherichia coli. Infections were induced by quarters and with time intervals. Hence, when the animals were slaughtered six hours from beginning of the experiment, epithelial samples could be collected from cisternal walls and lactiferous ducts which, by the time of sampling, had been in contact with pathogens for one, four, and six hours. Highly acute mastitis began to develop two hours from experimental infection and exhibited typical clinical symptoms, including general disorders, unambiguous alterations to the white blood count, and changes in milk composition. These changes were typical of acute toxin action on the udder quarters. Concomitant reactions of non-infected control quarters, detectable by clinical manifestations or by laboratory diagnosis, were not observed.