
Having just done an AI with my bitch, she was progesterone tested on day 7 as a normal bitch would be then not again until day 10 then she was done every day from day 13 til the day she ovulated and inseminated 2 days later. The surgery who performed the AI are my usual vets and they recommend to do a test on day 7 then if it is a low reading then perhaps not again until day 10.
I tend to know my own bitches and the bitches I have now have all been late ovulaters at about day 18/19. In general I don't start progesterone testing until day 10 for the 1st one. I watch them when they are having phantoms and know when they are 'having pups' which has saved me a lot of money in the past!
I have also had one bitch who swung her tail on day 1 of her season and she was tested on day 4 and had already ovulated so was mated and had 11 pups. Her next litter she ovulated at day 14 and the final litter day 19.
Another bitch my parents owned was mated on day 11/13 before preogesterone testing days and she missed 3 times. On her next season on day 1 her brother mated her and produced 8 pups! They were all sold as pets and not bred from.