The percentage of cornified cells is what your veterinarian is looking for under the microscope when he takes a vaginal swab. As the hormones switch and progesterone takes the place of estrogen this acceptance will occur. Most practitioners test progesterone rather than LH because the LH surge can be as short as 24 hours and can be easily missed. At the first noticeable signs of heat you should bring your female to the doctor for an examination. This is because some bitches have a very slight discharge during proestrus or you may not have noticed it right away.
Timing is the most crucial aspect in breeding dogs, period.
If all goes well, ovulation will have occurred and viable sperm will be awaiting the eggs as they arrive in the uterus. Conception will follow and in about 60 days puppies will be born. Pregnancy can be confirmed as early as day 14 by palpating the uterus, as early as day 21 by ultrasound, or on day 28 through blood testing. Radiographs can be taken at day 45 when the fetal skeletons start to mineralize. As always, you need to be able to answer some questions for your doctor.