Mean Marley- from friendly too ferrel!

Well ever since Marley was desexed he's turned into a little b******! I doubt it had anything to do with being desexed more just a coincidence...

He has always been happy go lucky mad Marley. OBSESSED with other dogs, always ready to play...
However this change in behaviour is very undesirable and has left us embarrassed on more then one occasion. Each time its been a puppy not an adult dog that has unknowingly upset him and each time his reaction has been the same, he starts growling ferociously and stands over the other dog in a very dominating manor.... !!!!
Why would he suddenly start bullying other dogs?!?! And the puppies aren’t always little the latest incident was at the vet clinic today and it was a 6month old Samoyed puppy...

I don’t know how to stop him from doing this or why he would do it in the first place....
Any help would be appreciated!!

You need to go talk to a trainer. This has nothing to do with neutering -- it has to do with the fact that he is an adolescent and at a point where his behaviour needs managing and training. You need to understand whether this is just play that looks like aggression or is actually becoming aggression. Have you had him to classes?

If one of mine did this in the vets they'd be put immediately into a sitstay or a downstay -- which is a position in which they cannot get into this kind of misbehaviour. If he isn't able to be put into a downstay because he doesn't know these commands, then he needs obedience classes immediately and you really should talk to a professional trainer right away. In other words, if he is able to act like this and has no self control or you can't give him other tasks to do that remind him that this kind of thing isn't acceptable and that he always listens to you first -- then he very much needs to get into formal classes and also I'd want a trainer to assess this behaviour towards other dogs. Also you don't want this further developing into regular aggression against other dogs -- sounds like he needs wrk on socialising and interacting politely with other dogs, that a good obedience class would provide.

Now that said: he is getting to be a young adult -- he is not a puppy anymore and will be defining his behaviour as an adult, NOT a puppy now -- and it is often quite NORMAL for adults to tell puppies to get lost as puppies are *annoying* to a lot of adults. If he only ever does this to puppies, then he is the type of dog that finds puppies annoying and this situation is easy to avoid -- don't let him interact with puppies (or more to the point -- don't let puppies pester him). But this needs to be done in conjunction with the above -- you need to be able to control him in public situations so that he isn't ever given the option of roughhousing with puppies and he needs to know to respond to you. I'd find a rewards-based training class and go to work.

PS Jaspar and Lily do not care for puppies; Leo and Lucy like them. All dogs are different just like all people are different in their interest (or lack of) to be around small children.