Spaying/Neutering is a guarantee of nothing except that the dog cannot reproduce, and that females cannot get pyometra. Some owners will report behavior changes, but really you won't know what exactly those behavior changes will be or if there will be behavior changes at all.
Resource guarding is likely genetic, so other than keeping items the dog likes to guard out of reach and training for alternative behaviors, there is nothing medically that can be done.
Resource guarding is likely genetic, so other than keeping items the dog likes to guard out of reach and training for alternative behaviors, there is nothing medically that can be done.