If you're going to post something breed specific, be accurate...
From the standard:
The amount of white will typically affect the amount of pigment on a newborn, those with more often take a little longer to fill in, in my personal experience with Aussies. But don't forget there are types of 'white', eg a samoyed and perhaps even a poodle is actually caused by a different gene to the white patterning of other breeds such as mine.