Milk-flow, ultrasonographic, theloscopic, and histopathological characteristics of the teat in cows with toxic mastitis.

The milk-flow, imaging, and histopathological characteristics of the teat in five cows with toxic mastitis were investigated. Teats were grouped into type I (without gross and histopathological abnormality), type II (no abnormal gross findings, but with histopathological abnormality), and type III (with gross and histopathological abnormality). Normal teats from six cows served as controls. Type II and III teats had lower milk-flow, compared with the controls. Ultrasonography revealed no abnormal findings, except for irregular mucosal surface in type II teats and absence of hyperechoic line along the teat canal in type III teats. The theloscopic findings varied from normal to mucosal abnormalities in type II and III teats. Histopathology demonstrated epithelial changes, congestion, hemorrhage, edema, cellular infiltration, and elastic fiber degradation in type II and III teats, with the type III teats showing severe changes. Toxic mastitis was characterized by impaired milk-flow and various degrees of imaging and histopathological abnormality.