Other translations use Donkey in places as well, I wonder why ? the Etymology of "Ass" goes back through Greek and Latin all the way to Sumerian, the Etymology of Donkey only goes back a few centuries, and was slang even then !
I think because, especially in the U.S "ass" is used as you guys above have, and is increasingly here in the U.K, these translators don't want any confusion.
For Bum or Backside or whatever I prefer the more ancient spelling "arse", so one is clear that he is not speaking of a member of the horse family.
Said in a Posh English accent "You silly arse" has such a ring to it. *
However, I do love *Double Entendres, and the resultant schoolboy laughter that follows, so regret the substitution of "donkey".
I suppose Shittim is still in the RNWT ?