
It is not unsual for a bitch to carry on discharging after a mating some do.
What does it smell like? If it is a 'fishy' smell then this is normally an indication that she is ready for mating and the 'fishy' smell is a turn on for the male dog!
If at all concerned about about the smell I would contact your vet, but it all depends on what it actually smells like.
I have a vaginal swab done on my bitch before I mate her to make sure she has no infections before mating this is normally done on day one of her season.
I am sure there will be some more experienced CD'ers replying to this post, but in my own opinion unless the smell is a 'horrible' one I would not tend to worry xx