I believe it easier to breed my dogs when I have kept good records. For example, if I have a bitch bred on day 10 of her cycle and she whelps 66 days later, then I know that I could have bred her on day 13, as bitches usually whelp 63 days after ovulation. If I had done so, we likely would have had more puppies. The next time I will have her bred later in her cycle. It is also helpful to be able to predict when she will come into season next. If you use this chart or one similar it will help you to plan better.