so bit of background male entire 17 month old weimaraner fantastic temperment (up till now!) fab with my kids very obedient generally
hes always been a little unsure around dogs he always seemed a bit wary but with lots of socialisation he settled down and ive been able to walk him in heavily populated dog areas with no probs
however the last couple of months hes turning into a beastie with other dogs predominatly males he will attack with no provication from the other dog he is awful on the lead if they approach him and at the moment i wont have him off the lead around other dogs
any tips anyone??
im quite aware this is most likely hormone related the dreaded 'kevin stage'!! i would consider castration if ness but would rather trial the implant first if this is the general reccomendation
this dog is fantastic and bar this issue hes been the perfect dog so id really like to get on top of this

thankyou in advance :)

It doesn't bode well that he has always seemed wary around dogs...

A puppy which is under-socialised often grows into a slightly wary adolescent, and then an aggressive adult.  During puppyhood and early adolescence, dogs frequently don't have the confidence to use aggression, so you often see just the fear.  Then, as they get a bit older and the hormones really kick in, they suddenly have the confidence to 'defend' themselves from whatever it is they are afraid of.

To owners this comes as a total surprise and shock and seems to be out of the blue.  But the warning signs have been there all along, in the fear.  If owners knew that the fear would turn into aggression, they would have done all they could, earlier, to address it.  Instead the fear by itself doesn't seem such a big deal and so it goes unaddressed...

I definitely would not recommend castration as a knee-jerk reaction:  Castration removes the dog's confidence, which might just leave it with even more fear as a result.  It's possible that castration can work, but it should be carefully thought out and - as you say - trialled firstly with Tardak - so you can see if it improves the situation.

I think first of all, though, you need to work with a reputable APBC behaviourist to address the issues properly and under supervision.

My boy decided that he was all 'man' after we had had a (castrated) foster dog here that definitely wanted to be in charge, this caused us some problems as he started facing up to other dogs when we were on walks. He also started to react quite strongly when one of my bitches was in season.
We tried the superlorion implant on him rather than go for the castration to see if it would help matters

I have to say that the effect has been all we had hoped for, he has stopped trying to face up to other dogs and had no problem with the girls when they came in to season. The implant is supposed to last for about 6 mths, his was done in June 2011 and we have not had any apparent problems since and it must have worn off by now. I should add that he would have been about 18mths when the problems started and we had the implants done when he was 2 1/2yrs.

So I would say if you are not sure that castration is the answer then investigate the implants in the first instance to see if the effect is what you wnat, it has worked for us and his behaviour is much better since

Sometimes changing things with drugs gives the dog an opportunity to associate feeling differently around the trigger.

The same effect can be seen with separation anxiety, and drugs often prescribed for it:  The drugs provide enough of an opportunity for new associations to be made (ie - being left isn't terrible after all), so that even when the drug is discontinued, what has been learnt, continues.

It doesn't always work that way though.  Some dogs do need the meds to continue, and some dogs would need to be castrated/have the op for the effects to be permanent. 

Again:  Neutering is not always the answer, for all dogs.  Some dogs, it makes aggression worse.  It's best to work with a behaviourist so you can effect behavioural changes and maximise the advantages that any drugs can give.

Male Weimaraners can go through a very tedious period when they are at this age, however it is vital not to permit them to practise unacceptable behaviour.

Do not allow your dog to be approached when on lead as he will feel out of control and react inappropriately as he cannot choose to leave etc.

Also, be extremely careful what dogs he is allowed to interact with, so he does not have the opportunity to rehearse bullying behaviour.

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Male Weimaraners can go through a very tedious period when they are at this age, however it is vital not to permit them to practise unacceptable behaviour.

Do not allow your dog to be approached when on lead as he will feel out of control and react inappropriately as he cannot choose to leave etc.

Also, be extremely careful what dogs he is allowed to interact with, so he does not have the opportunity to rehearse bullying behaviour.

You say you live in a heavily populated area with no problems, it may be that he is now "overloaded" and has now snapped.

Have you had the vet give him the once over to rule out any underlying medical issues? If so then I would ask for a referral to a reputable behaviourist (who will not see a client without one) for help.

Have you talked to his breeder?

I had a pack of dog-aggressive dogs.  The key is not to castrate but to re-train.  This behaviour should not be allowed.  When my top dog was younger, he was walked mostly on-lead or off where I could see for miles(to watch for dogs approaching).  I would shout to other dog owners that my dog was aggressive with other dogs and they would mostly put theirs on the lead to pass.  My dog went to obedience and show training classes so he was very well behaved and would ignore(thanks to the weaving leave exercise) on command.  As he got older, I could trust him to stop on command so I could put him back on his lead if I saw other dogs coming.  My dog was alwasy under control so if any incidents happened, it was always because the other owner couldn't control their dog not to come too near.

PS  My dog was never scared.  He was very dominant(breed trait).  I've heard of fear aggression getting worse through castration so it's worth talking that over maybe with a behaviourist.

Just to add on to the advice given already:  NEVER tell him off for any 'bad' behaviour towards other dogs.  Never.  He will be focused on them, the telling-off (or punishment, be it even a tiny tug on the lead or whatever) will be associated with them firstly, and secondly will in itself cause stress.  So the next time he sees a dog, he'll be worried about a) the dog and b) what might happen to him as they get closer/he interacts.  Basically double the stress, which equals double the reaction.

If he does anything 'bad' just walk away, if he does anything good - or even nothing at all - praise and reward with something very valuable to him (calm praise).  I have overcome greeting issues in some of my dogs simply by clickering them for good or neutral behaviour around other dogs - it's such a simple idea but it is hugely effective.