So what does all of this information regarding the ancient African kingdom of Cush have to do with the English {I presume} folk song "Cushie Butterfield"?

Maybe nothing. But I have often wondered what happened to all those enslaved Africans who were brought over to and lived in England prior to the 19th century. It seems reasonably to assume that most if not all of these Black folk became racially mixed folks who became whiter and whiter every generation until they just became White.

Could "Cushie" have originated as a nickname for a English girl who was less than fair skinned? That's my theory and I have absolutely no proof for it except the etymology of the word "Kush".

As to how "cushie" became a pet name for a cow in Australia and maybe elsewhere, I have no idea.

As always, I'm interested in others' input regarding "Cushie/Cushy/Coushy" in the context of that song or otherwise.