Has she been hip scored as this is a very big problem in this breed? You need to make sure that she has all the health tests and also that the sire does. All bitches are different, if you are going to a good stud owner they would be able to advise when the right time is and so should the stud dog.
There are lots of Douge de Bordeaux puppies being sold at the moment, I would be sure that I had homes for puppies before you breed, I know of one site that has at least 8 litter for sale, some being 17 weeks old and at a vastly reduced price.