Lab aggression turn for the worst

Hi Guys, let me first say sorry because this is going to be a long winded story! Any advise welcome.
Archie is my beloved 6 year old golden Lab, a couple of years ago I had to go and live with my mum for 3 months and up untill this point Arch had been great with other dogs. My mum had a corgi and since Arch was a babe they had got on great and the did for a while when I moved in. ( they would sleep, eat and play together). My mums dog would sometimes have a go at him but he took no notice untill one day he had enough and all hell broke loose.. I got bitten and so did my mum. ( I did say it was going to long!!!!) Since that day he became very dog aggressive and will not tolerate any other dogs coming into his space, he will not actively go for them and wont bark or growl at dogs say the other side of the road but if they come too close he will pretend they are not there then if they persist he will go for them. Anyway, he kept one very close bond with another family members rhodesian and this was the only other dog he could go with, they played so well together and I would go as far to say he adored him. Not today though... today he attacked him. So now there are no dogs he can go near. What do I do? Walking him is miserable and stressfull. We are in Newquay so the beaches are now out of the question. Is he just over dominant? Would castration help? My fear is that if he can turn against his "best friend" could he turn towards humans so quickly. HELP

I am a bit confused as you say you are in Newquay but your profile says Camberley?

In any case you need the help of a reputable behaviourist most of which will only see via a vet referral.

What does your vet say?

Hello. Couple of things:

Castration probably won't make any difference to his behaviour at this point.

Aggression towards other dogs will not translate to aggression towards humans. They are two completely different things.

The fights that have occurred between Archie and the Corgi and the Ridgeback -- were they proper fights (where damage was done to one or either dog) or "handbags at dawn" scuffles which sounded horrible but no damage was done?

It sounds to me like contacting a reputable behaviourist who can come and see you in person would be the best way forward.

Hi, I was in Camberley but now moved to Newquay, just forgot to update profile. They were proper full on fights all of them, didn't draw blood but I think that was mainly down to quick reactions from us ( hence why we have been bitten). The vet suggested the castration but I wasn't too sure if it was too late for that. What could the reasons be for the sudden change towards the ridgeback when he was fine untill today?

Hormones.

If you have no reason to keep the dog entire then you may consider it, however castration rarely works without behaviour modificaton programme.

You can try the Superlorin implant if you do not want to go the whole hog.

Having him neutered won't make any difference now.
I don't agree with a ''dog being aggressive with other dogs, will be aggressive with humans'' as he is 6 is he in good health, ie no aches and pains in his joints.

The fact that he stood for your Mom's corgi before he let rip, shows that he could of just been fed up with your Mom's corgi having ago, ....I have male here that can be like that with dogs outside his pack.
You say he doesn't actively start anything, but hates his space invaded, so that shows that he has control of his feelings.
Are you sure the Ridgeback didn't do something....did you see the body language before hand.
You say it happened today yet say ''he can go by no dogs now'' thats almost like you are speaking for him/his feelings.
TBH if you do that then you run the risk of making him more aggressive IMO so I would advise a Behaviourist to help.
I do not stop Bruce from going near other dogs although he would just walk past them, I just inform people, ''don;t let your dog run/play/in his face/ at him as he likes his own space'' that way Bruce has no problems with other dogs and will walk happily with a large group of dogs

You have my full sympathy, we have an almost identical history with our lab and my FIL's JRT. My advice is the same as above, get a GOOD behaviourist, APDT registered. There is another reputable body for them to be registered with too but I forget the name, sorry. That would be the best thing you could do right now.

Just a note the APDT is for dog TRAINERS
The APBC is for behaviourists and COAPE and UKRCB

He is in good health, so I am ruling out any obvious things that could make him narky. I think he can control his feeling its just that it happens with almost every dog he meets. I cant let him off the lead for fear of another dog wanting to play and running over to him. When I said that he can t go with other dogs I meant off the lead playing coz the rhody was the only one. Its just made me sad that the bond has broken. The rhody did nothing out of the ordinary it was completley unprovoked. We can walk past other dogs on the lead he will sniff but only for a second before the hackles come up, and other owners dont seem to keep their dogs away when they see he is on the lead which is what makes it stressfull.

I did wonder about the castration coz he will go for pups as well and they are no threat to him.????

I would deffo see a behaviourist if he goes for pups too, has this just started?

If so make sure the vet has given him a full once over.