Just read the closed post about someone with a blue and white collie.... someone posted that they though it was merle....

blue and white is a solid colour (dilute of the black colouring), blue merle is a black based colour with merle gene (not a colour but we see it as a colour) which dilutes the black, but is not a dilute colour.... means that the dilute of blue merle is called 'slate merle' :-)

Blue eyes were mentioned which is an indication of merle/dapple pattern which is why I think the poster was concerned that the OP didn't know enough about their dog but was thinking of breeding from it, not least to a completely different breed because it too happen to be blue.

Would 2 blues from different breeds still cause CDA in the pups?

Also there was no opportunity on that post to give reasoned arguments against the mating. The OP will undoubtedly have seen and possibly know lots of whippet x collies, it's a common cross. However these matings are usually done for working purposes. Most of the pups will go to working homes with the odd one or two left over going to a pet home. If the whippet in question isn't a working dog then they will find it very hard to find homes for an entire litter of pet bred crosses.

I'm not sure why that post was locked - it didn't seem a wind up to me.  They asked a genuine question and are probably confused now.

blue and white dogs are 'allowed' a different eye colour to black and whites, Merc had very grey eyes which have browned slightly (he's 12 months of age), there is no known problem with putting two dilute dogs together (unlike two merles which is a complete disaster), the alopecia which can be expressed in dilute dogs (but carried by solid coloured dogs) ie it's not caused by being dilute, just expressed by dilute, no reason why it's more common in two dilutes as opposed to a dilute/solid although clearly it's only expressed in dilute coloured dogs...... normal health tests should be done and really with whippet/collie cross the male should be the whippet!  I would have liked to have seen the thread move forward :-(

but is the dog actualy blue as they described it as
grey at the routes and darker nearly black at the ends

Shouldnt it just be blue right through the coat? Whihc is why i think someone said it sounds merle.

I had a blue tri colour border collie and he was a solid colour.

Very much like a dark grey but with a definate blue tint on his coat.

He had lighter brown eyes similar to some chocolate labs.

to be dilute it wouldn't have any black on it at all.... unfortunately we weren't able to ask the op any more questions..... it should be a grey colour throughout with a grey nose.... however it didn't sound merle either, as the coat should be in more like blotches... but we may never know now :-(

'Blue eyes were mentioned which is an indication of merle/dapple pattern'

Not necessarily. I have quite a few dogs here with a blue eye(s) and they are black and white dogs, not merle or dappled.

(And I do also own merles, so know the difference.)

yes there are genes for blue eyes, dilute dogs may well have grey/lighter eyes, merle dogs can have blue (if the merle goes across the eye) or by genes... apparently tri merles are LESS likley to have blue eyes than two coloured merles... illustrated by my Ski (blue tri) having blue eyes until he was about 7 months old and then they changed to a light hazel colour, his litter brother (red/choco merle) has blue eyes

Yep, blue eyes not necessarily merle in collies, just another colour gene :-D