G'day Joe,
I see that someone (presumably a compatriot) got back with much the same reply I was considering. The usually interesting references (like Brewer's Dictionary of Phrase and Fable just refer to 'sticking' - stabbing the jugular as the usual way of killing a pig. There is no mention of any more tender areas.
BTW: If you have replied to my reply to your query, I will get back to it on Monday, when I get back in front of the work machine. When I iron out some problems with this new connection to Netspace, I may shift my cookie to this machine and be in better contact.
Regards,
Bob Bolton