As the final plague, the death of the first-born, approaches, Moshe warns Pharaoh that the final plague will kill all the human first-born and "all the first-born of cattle". (Shemos/Exodus 11:5) The devastating death of the "all the first-born in the land of Egypt shall die, from the first-born of Pharaoh that sit upon his throne, even unto the first-born of the maid-servant that is behind the mill" is obvious.  What exactly does the death of all the first-born of cattle add to this, especially since previous plagues, particularly Dever, a plague that killed the Egyptian cattle, already inflicted serious losses on the animals? When G-d first warns about the death of the first-born, He does so long before in Shemos 4:22-23 even before Moshe has arrived in Egypt. "And thou shalt say unto Pharaoh: 'Thus saith the LORD: Israel is My son, My first-born. And I have said unto thee: Let My son go, that he may serve Me; and thou hast refused to let him go. Behold,...