PMC

A fragile area of the horn was observed at the toe of the left foot. A progressive fine linear cavity ran through the middle of the fragile lesion. In this picture, a cross-sectional surface of the cavity shows a punctate hole between the stratum medium and the stratum internum.

In the horn zymography, the keratolytic activity of each isolated bacterium (from No. 1 to No. 5) was visible as one to four white bands in the water-soluble horn-combined acrylamide gel stained with Coomassie Brilliant Blue (CBB) in the secondary screening examination.

One of the culture results from the horn powder agar-translucency test: The strain in (corresponding to No. 2) appeared as a yellowish colony and presented a stronger and wider translucency characteristic around the colony on the horn powder agar than other strains. The colony in on the right side of No. 2 showed weak translucency, whereas had no translucency characteristic.

A large number of Gram-positive bacteria were attached to the border of the hoof wall cavity (a) and invaded and proliferated inside the horn tissues near the cavity (b). All bacteria were observed within 300 µm from the edge of the lesion in the depth direction.