
Hi
Some bitches just don't read the text books .. they love t keep us guessing LOL. I don't think what you are seeing will be related to the herpes vaccination, especially in light of the erratic seasons you talk of previously.
I would recommend you ask the vet to run serum progesterone tests to establish what is happening hormonally with your girl, NOT the in house pre mate kits - the blood will need to go off to a lab. Blood draw in the morning and result by evening. This will give you an exact level of progesterone and you can pin point day of ovulation and therefore can go to dog on just the right day. If she is not giving you much indication of where she is at in her season I would start testing from approx 7 - 8 days from when you saw blood and repeat tests at every 2 days until you get to ovulation. Lab result usually include a recommendation for re test day. It is not cheap to the tests but they are invaluable for bitches with seasons that are difficult to read. My Sh Ch girl is very hard to judge but using this this testing system she produced two litters of 9 / 10 respectively in 2004 & 2007
Good luck
K