B.C.
The cat is only defending himself.
He's just old and relatively helpless and wants to be left alone.
A 4.5 yr old has a better understanding than a toddler.
She should know by now that the cat is not a stuffed toy and feels pain.
It's amazing DD has been scratched up and continues to go back for more.
I don't suppose you'd consider spanking DD whenever she goes near the cat(s).
If you can't keep them separated, it would be kinder to find another home for the cats.
You can't let the animals and child damage each other.
If daughter has no empathy/kindness for pets you might not be able to have any till she's much older.