When to breed your dog is an important factor to consider. The leading cause of unsuccessful matings is improper timing. Dog breeders seem to be day oriented. They want to breed on the 10-14 days of the heat cycle. Ovulation can not be predicted by just counting the days of the heat cycle. You may miss the early signs of a heat cycle. Some dogs show no signs or evidence they are in heat. Ovulation can occur several days after your dog is in standing hat. When the eggs are shed they must mature for 72 hours, before they can combine with the sperm. The sperm are able to survive for up to seven days in the female reproductive system.
Most breeders recommend that females be bred three times. They should be bred on the 2nd, 4th and 6th day of standing heat.
An important factor is how the female reacts to the male. Does she play coyly and does she flag? Flag means she raises her tail, presents her behind and stands firm for the male. You should see signs of softening of the vulva and lightening of the discharge. The discharge should go from red to pink.
You can have your Vet take a smear to determine the optimum mating time for your female.
A stud dog that is experienced will make his own investigation. A knowledgeable one ignores the female until the right moment.