Exodus 9:1-9 NIV
Then the LORD said to Moses, “Go to Pharaoh and say to him, ‘This is what the LORD, the God of the Hebrews, says: “Let my people go, so that they may worship me.” If you refuse to let them go and continue to hold them back, the hand of the LORD will bring a terrible plague on your livestock in the field—on your horses, donkeys and camels and on your cattle, sheep and goats. But the LORD will make a distinction between the livestock of Israel and that of Egypt, so that no animal belonging to the Israelites will die.’ ”
The LORD set a time and said, “Tomorrow the LORD will do this in the land.” And the next day the LORD did it: All the livestock of the Egyptians died, but not one animal belonging to the Israelites died. Pharaoh investigated and found that not even one of the animals of the Israelites had died. Yet his heart was unyielding and he would not let the people go.
Then the LORD said to Moses and Aaron, “Take handfuls of soot from a furnace and have Moses toss it into the air in the presence of Pharaoh. It will become fine dust over the whole land of Egypt, and festering boils will break out on people and animals throughout the land.”
NIV: New International Version