I have a bitch that from first mating would be 64 days today but from last mating she would be day 60.  How long before I should be concerned at no puppies arriving.  The bitch seems fine in herself, still eating and her temp has been constant around 37.9 all week.  I look forward to hearing what people think is a safe time to wait

Hopefully someone will be on soon that has actually experienced a very late whelp.  Mine always seem to go early!  I have only had one go to day 64 - no problems.  In your own words, she seems fine in herself, so I wouldn't be too worried for a couple of days yet - you know your girl, and would notice any distress.  I'm sure there will be a CD'er that can give you more help later.

Breed specific I'm afraid.

I have had one particular Boxer bitch who whelped 4 days and 6 days late respectively in her 2 litters. All went well and my vet commented that as as long as my bitch was well and the pups had strong heartbeats, they were pretty safe in there.
But I would not let a Cavalier go more than 1 day late. They very often whelp 4 or 5 days early Boxers don't tend to.

I would ask an experienced person in your own breed for specific advice.

Her temp is spot on normal for being in whelp. I would continue taking the temp as this can be your first indication of delays.   60 days to the second mating would make her fine so I would expect her to go any time in the next 3 days.   The temp will drop down into the 36 area and stay down there for a good few hours general 12 hours before whelping

just a quick update .... been to vets, he has had a good prod and poke and feels that there is nothing amiss so he wants to leave alone for now.  If nothing happens by wednesday he will review her again but he thinks her eggs fertilized a long time after mating, hence a long pregnancy.  Obviously if I feel that my bitch is haveing problems I will be straight back to vets!!!

yet another update .... we have 2 beautiful puppies born yesterday.  Very large so guess that is why she was reluctant to let the go !!!!!!!!!!!!!

ah congratulations, I am pleased that everything went well :-)

congrats :) my girl was the same when to day 63 and had 2 pups and big one at that!

great news:) my girl went 61 days and had 4 large pups ......lots of fun to come :) are you keeping 1? or both :) small litters are fab im loving every min of it ,ive got such a bond with them !

I cannot keep one ..... we have no facility to keep a boy as we have a number of girls ..... now if they had been girls they would not be going anywhere!!!!!!!!!!!!!!, It will be so hard to let the 2 little ones go