Figure 1.

Experimental setup of infection with E. coli 1303. During estrus, 10 synchronized dairy cows were infected on one quarter with E. coli 1303 (star, i) in saline solution (shaded). One of the neighboring quarters (n) was treated with sterile saline solution (shaded). Five synchronized healthy animals were slaughtered 24 h after onset of estrus and served as external control (c). Tissue samples were collected from marked areas of the bovine udder.