Before She is Spayed. The best time to spay your female is before her estrous cycle. Cats are spontaneous ovulators, meaning the female does not go out of heat until she is bred. This assures fertile mating and also explains why we have such a serious overpopulation of cats. Cats can actually become pregnant while nursing their young.
Male cats tend to reduce territorial spraying, depending upon their age at neutering.
Neutered dogs and cats fight less, resulting in fewer battle scars, contagious diseases and abscesses. Males also wander less because they aren't as interested in pursuing females in heat. Also free of the urge to mate, dogs and cats tend to be more content and calmer. Neutered pets are easier to live with. However, guardians over-feeding them, and not providing enough exercise usually causes weight gain.