Rosina
We asked our vet's advice and he said there was no reason that he knew for waiting until the first season was over. We took his advice, and our 6 month old was bright as a button the day after surgery. I'm not sure why one season is ever suggested - can anyone enlighten me?
When animals are growing, the bone growth takes place from a site at the end of the bones called the growth plate. Sex hormones, like estrogen and testosterone, close the growth plates. If a puppy is spayed or neutered before their bones are done growing, the closure of the growth plates is delayed, sometimes by several months. The result of this is that the dog will get a little taller. We also know that dogs that are spayed or neutered, are more prone to tearing the anterior cruciate ligament (ACL) in their knees. It is not known if asymmetrical growth plate closure, or other factors, like the tendency to become overweight after spaying or neutering, is the cause of this predisposition to ACL injury. In an ideal world, dogs wouldn’t be spayed or neutered until their skeleton is fully developed.
Hope you're now enlightened.