
The first signs thatr a season is likely soon is scent marking, squatting frequently to pass small amounts of urine (though of course this can be a sign of cystitis or similar also) some bitches also become sensitive about having their rear ends touched or sniffed by other dogs. She may also become a little exciteable or withdrawn and mopey.
Her vulva will also become gradually larger than before.
when you think that she is thinking about coming in season dab her vulva each day with white tissue, preferably just after she has been resting or had a pee. When you see blood stain the tissue you will have day one of her season. she should be kept on lead and away from male dogs for at least 3 weeks, but preferably four.