Hi thanks everyone,
just as variable then as the other breeds really, despite what the Book nof the Bitch says.
It is not variable. It only depends on the day you start to count and it usually starts when the bitch is mated which does not always match to the day when eggs are mature. When you start at this time, it is 61 days (whatever the breed).
I'm a little confused here or my dogs are exceptions to the rule.
Both had premate tests done, first one because it was my first time and I was travelling quite a distance had had already gone too early (no mating took place). Penny's premate test said probably ovulated mate immediately which happened the same day. She did not tie so she was mated again the day after. Penny went exactly 8 weeks from first mating which is 56 days. 57 days if you take it from 2nd mating.
Phoebe had a premate because it was one mating. I had a dog at home and was pretty certain she was ready. Had premate just to help that said again probably ovulated worth mating vet nurse said it was the last thing before it's too late. She whelped at day 59 from her only mating.
If the eggs where immature fertilisation would have taken place later because eggs need time to mature and if eggs were too ripe they would have probably missed as sperm couldn't get to them quickly enough.
The length of gestation according to the canine reproduction book is more variable when measured from day of mating having an average of 63 days but a normal range between 59 and 70 days. Gestation is much less variable when the onset of diestrus is used to calculate the length as on that date all the bitches are at the same stage of pregnancy. The average length when diestrus is used is 57 days, but then if you count from the day of conception the average using this method is 60 days. I can't see anywhere where is states it is always a certain amount of days only avaerage lengths.