Thank you for your reply, Karlin. I find this all very interesting. Would you be able to give me the link to this SM email list ? I would like to read more about this discussion.
Thank you Karlin and Rod for your reference to the research on the changes that occur during early fetal development. It certainly may be correct, but it still leaves me wondering.
A very timely thread as Rosie has just caught us out by coming in to her 2nd season only 3.5months after her first. So her planned spay will have to wait until December now, hopefully she wont mess that up by coming into season so quickly again! She's a year old and I think fully grown height wise (same height at withers as her mum, and she was the smallest pup in the litter so I don't expect her to get bigger than her mum), which implies closed growth plates - only a scan or x-ray would show that for definite though.
It is interesting to read all the differing viewpoints, but ultimately we all do what we think is right for our dogs.