I did a search and could not find it. When someone said Whelping would be 61 days ? from when the girl reach 5.0 on her progesterone test ? Was that right ?
Older we get the less we can seem to keep straight.

63 days (or 9 weeks) from ovulation (when progesterone hits 5.0)- was the way I was taught to calculate a due date.

Try this link.

http://www.schaferhund.com/gsd_pregnancy.aspx

Interesting. I have never seen that. I have a whelping calendar, just thought some were saying something a little different lately on here.