Sorry for bombarding you with questions and long posts but here is another one:
I have always spayed my females at 6 months old but found that they grew long legs after that, and were generally narrower, than their intact litter mates although that was not a big deal to me.
Then my last dog struggled with bilateral ACL ruptures and researching it I came across studies that suggest that ACLs more often occur in spayed dogs than intact dogs (one study found that out of 48 females with bilateral tears, only 2 were intact). Nothing written in stone but the medical community is looking into this.
It is a known fact that the growth plates don't close until 8-10 months of age (?) and that removing hormons via spaying at 6 months or earlier will affect bone growth; the bones become narrower and longer, although bone density does not seem to ge affected. HOWEVER: angulation, corelation of joints and bones etc may change, possibly making some dogs more prone to joint injuries.
So my plan this time around is, and every breeder I have talked to agrees, to wait until she is done growing, at least 12 months, even if that means that she may have to go through one heat. My vet (a new guy at the clinic) however disagrees because of the cancer risk goes up as you wait (reduced by 95% before the first heat, and 80% after the first heat).
What kind of annoyed me is that he said that because she is not going to be shown it doesn't matter if her conformation changes and that she will be taller and leggier. I mean, the breeder took great care in producing these wonderful, functional dogs - why not let Tessa grow up to look like she is intended to look? Do I have to settle for less because we are not in the show ring? More importantly, what if the changed conformation will result in more wear and tear on her joints? I thought there was a reason why their bodies look the way they look. Or am I missing something?
It's not that I don't want to spay her, just want to give her an additional 6 months to finish growing. BTW Tessa's breeder said that her dogs go into heat very late, at around 15 months.