Well,it depends on what type of aggression the dog was showing to bigin with?If it was jumping on owner,mouthing ,disobedience,barking,scrachin g on door etc.it was not male aggression but spoiled kid refusing to grow op.That will not change due to FIXING.But male aggrresion,scent marking,dominance fights with other dogs or even owner will subside on fixing.The male hormone Testastrone most of it can not be produced anymore and hence the male aggression that was necessory for the animal to propagate its genes over others but not as a pet.
Bangalore corp. pays NGO s Rs.450-550 for catching a street dog,surgery,post operative and release to the same location. Same if u take ur dog there.Add extra for extra care.Surgery takes 15 min,and dog can go home in 4 hrs.It will fully heal in 4-5 days.
Do not perform this before dog is physically and mentally grown up .i.e. atleast 12 months.Reason, the hormone I mensioned above works in complex way and is needed for proper development of dog.U may even apt for semen preservation (Rs.10k /per year) if u want .