Often males that are neutered too young do not develop the confidence they need and suffer from fear aggression. they are also often attractive to entire males due to feminisation syndrome and become aggressive due to the unwanted attention.

As Siberians are a very slow maturing breed I wouldn't advise neutering him before he is 18 months. Be prepared for extra work with his coat as the coat tends to get longer and thicker when they are neutered. Be careful with the feeding too, Siberians need less food than other breeds of this size anyway, they were originally bred to be able to travel distances on minimum calories, this trait has remained with them, it's surprising how little they need to eat to maintain a good body weight. When dogs are neutered their metabolism slows down so they need less calories to maintain their bodyweight. I always advise owners to reduce their food intake by 1/3 and this should aviod the dog putting on weight. All dogs are different some may lose a bit of weight so it can then be increased slightly to get a balance and others might still put a bit of weight on so either less food is needed or a light variety of food. Exercise can also be increased to help prevent weight gain.

Our surgery normally does smaller breeds at 6-9months and again they need a reduction of food after the operation.