the advice from vets is all different on this as well.
as u see from above one vet will do before 1st season so you have to trust the vet your with.
Our vet will not do it until after 1st season(bitch over 1year)he will also not give pups under 8weeks any jabs(not required) They dont like operating on dogs less than a year old(unless emergency)as young dogs cant always handle the anestetic reqd.
the bitches cycle is around 3 weeks but u may miss when it starts if u do not notice any blood(depending on surface)or it may be a dry season.
the bitch only ovulates for around 48hrs her scent will change (the dog will let u know when

)this is only time she will stand for mating.(DONT LEAVE ALONE AT ANY TIME DURING THIS)
he will howl and get a bit more excited at this time.
Axle has had to put up with it for the last 3 months as each of or bitches have went into season one after another.
Axle is not allowed any where the girls are peeing when in season (to prevent tasting)we always hose down
We never take bitches out on walks when in season as you dont want a pack of dogs outside ur home wating for a chance
hope that helps a bit nix