God smites the cattle he had earlier killed?

Exodus 9:19 says, “Send therefore now, and gather thy cattle, and all that thou hast in the field; for upon every man and beast which shall be found in the field, and shall not be brought home, the hail shall come down upon them, and they shall die.

9:20 He that feared the word of the LORD among the servants of Pharaoh made his servants and his cattle flee into the houses:

9:21 And he that regarded not the word of the LORD left his servants and his cattle in the field.”  This would be Ok except god killed all of the Egyptians cattle.  Exodus 9:6 says, “And the LORD did that thing on the morrow, and all the cattle of Egypt died: but of the cattle of the children of Israel died not one.” So what could they gather?