I have not had a female dog before getting this puppy. I have chatted to the vet regarding spaying, which he suggested we do around 8 months, as she is a large breed was of the thinking that she wouldn't come into heat prior to 8 months.
She is just 5 months now. These are the signs which make me think that she is:
We have an older male dog who is neutered. She keeps backing up into his face, and sitting on top of him if he is lying down. She always seems to sit on him near his face. I have caught her trying to 'hump' him twice now. He has arthritis as was not happy about it, and he snapped at her. I haven't seen her do it again within last few days.
She is pretty feisty, but she seems a bit more aggressive with the male than she was. She is even up in the night last few nights, barking her 'wanting to play' bark at 12 at night which is unusual for her as she sleeps soundly usually.
She doesn't seem to be swollen on the vulva and has no discharge.
Does this sound like she may come on heat soon? I also didn't think a pup under 6 months could be spayed...