Exodus 9:6-9

6And Jehovah did this thing on the following day, and all the cattle of Egypt died; but of the cattle of the children of Israel died not one.

7And Pharaoh sent, and behold, there was not one of the cattle of the Israelites dead. But the heart of Pharaoh was hardened, and he did not let the people go.

8And Jehovah said to Moses and to Aaron, Take to yourselves handfuls of ashes of the furnace, and let Moses scatter it toward the heavens before the eyes of Pharaoh.

9And it shall become fine dust over all the land of Egypt, and shall become boils on man and on cattle, breaking out [with] blisters, throughout the land of Egypt.