Your dog has a smaller range of colour with only tones of yellows and blues. So what it means is that red and green tones are also seen as yellow. He/she will also see a contrast based on brightness.
Pink and turquoise are seen as tones of greys, which obviously is quite different to our vision for bright colours.
So if your first thought was to get a red ball for the park to make it easier to catch, think again as both are perceived in the same tone, instead think of the brightness of the tone you chose, not the colour itself.
Finally if you are going to a fancy dress outing, he/she will not see the difference.. good or bad!