Hi, I know this is complicated but I have a question re coat colours in dogs, specifically related to breeding.
So I just had a beautiful litter of 9 pups with my maiden bitch - she is a blue dog with typical.collie white markings around her neck, paws, tip of tail and blaze on nose etc (oh and white stripe tummy) - she's a 3/4 greyhound 1 /4 collie (her mum was a blue greyhound, her dad a half collie x greyhound)
I mated her with a whippet x first cross bedlington - he is brindle and his mum was a black first bedlington x and his dad a whippet.
I was expecting some brindle pups but she produced 5 black pups and 4 blue pups (with some very small white splashes here and there)
So its like they've thrown back to their grandmothers colouring!
My question is, do pups coat colours change (they are one day old now) - ie will a brindle colour develop in any of the black or blue pups (there are slight variations on hue especially with the blue pups) ie could the blues end up "blue brindle" - I'm just really surprised there are no brindle pups (as yet) direct from the stud dad coat colour :-)
Many thanks for any knowledge - I'm so fascinated by the whole genetics in dogs...and this is my first litter, something I've wanted to do for 30 years!

You are aware that brindle is not a colour it's a colour pattern carried on a recessive gene & to show the pattern a dog has to carry 2 copies of the gene

If your bitch does not carry the brindle coat pattern gene you won't get any brindle coat patterned puppies

The black Kb gene is dominant over the brindle kbr gene.
So a brindle dog is kbr/kbr, where as a black can be either Kb/Kb or Kb/kbr.
(This is not including recessive black of course)

If there is no brindle dogs recently behind your girl or brindle siblings/arnts,uncles while there is a chance she carries the gene it's a good chance she doesn't. If she doesn't carry it she will never produce it, if she does carry it then each puppy will have a 50/50 chance to be bridle.

The width of the striping can varie a lot from thin to so thick the dog almost looks solid black. The colour under the stripes can also varie from the lightest creams to darkest reds.  Can you see any tan pigment on them?
A friend once has some very heavy sable pups who when born they looked solid black but after a little while the lighter hair started showing threw more and more.

Thank you these replies are so useful and all really interesting stuff! Very much appreciated!
We had a brindle bitch once (the only one in a litter of 7) and the mum was a deerhound x greyhound (browny/greyhound coat) and the dad was a merle collie - I didn't think there would be brindle in a collies heritage but I'm extremely new to all this.
Some of my bitches pups look like they may have a bit of tan - especially in one of the blue ones - but hard to tell at 2 days old..
I'll await to see what happens...as with if any long/rough coats will develop which is do hard to spot early on.. I can't imagine my bitch has any brindle genes but really interesting that all the pups have thrown back to both grandmas with predominantly blue and black.
So much for choosing a brindle stud because I was hoping for some brindle pups! But what a great learning curve and the pups are all gorgeous so its all good!
Thanks again for the detailed replies.

Colour inheritance isn't something I have had to worry about, much as I really wanted a lemon/white bitch - something that despite using a male with a lot of that colour in his background along with blanket black, which he was -  never happened.   I did have a male of that colour however a generation on.

Given the number of breeds in the background of the litter you have, I have no idea how you'd be able to be sure exactly what colour(s) might prevail.

For the record, my Whippet was bought as a blue brindle with white trim.   During the summer months however, she goes to a more brown brindle + white trim ..... and not for nothing did we call her Teazel (spelt that way).   Puppy coat colour does change as they mature (or at least my main breed did), starting off black and white mainly, before the black lightens and some tan develops (heads mainly).   Whether or not you'd get brindle I have no idea.   Along with anything else in that combination

You could DNA test for what colours are carried, and some patterns too.

Ooh I didn't even think of that! Of course I suppose that helps when choosing a stud..thanks!