We have a five year old male Weimaraner who is very complex to say the least.  He came to us at two years of age unsocialised and frightened of pretty much everything.  His fear led him to bite my partner several times, a couple of bites needing stitches, but we understood why he bit, so stuck with him.  He turned into a fantastic dog, although he can be a little unpredictable.  We can read the signs and difuse the situation however and he hasn't bitten in more than two years.  He has only ever snapped at my partner.

He is a very highly strung dog who adores my partner.  He howls to be with him and follows him everywhere.

Yesterday during the day when we were at work the dog appeared to have bitten or stung many times on the top of his head, his ears and a few on his body.  We have five dogs in total who have access to a fairly large garden and kennels when we are out.  None of the other dogs are affected.  The dog let us have a look at him, tail wagging furiously at the attention until we got to the bite on his ear.  We had growls and hackles up with tail still wagging away.  We read this as he was happy we were with him and looking after him, but his ear was painful so he didn't want us to touch it.  Fair enough.  We decided to see how he was today.  The lumps on his head seem to have burst like spots, all filled with blood.  He has been snapping at the other dogs, all bitches, and very unusual for him as he definately bottom dog.  He has been needy and clingly wanting us to pet him all the time and is happy for us to scratch his bloodied head.  We do have a couple of banks of nettles in the 'dog garden' under a bank of trees and it may be that this is the cause of the bumps.

However, a little while ago my partner came in a bit shaken.  The dog had pinned him against the wall, growling.  Casper (the dog) was still wagging his tail furiously while growling at my partner.  He does growl at my partner when he (the dog) doesn't want to be shut away for the night, things like that, but we just ignore him and goes to bed grumbling away to himself.  I wondered if he just wanted my partner to stay with him, hence the warning growls but tail still wagging? 

We are just at a bit of a loss as to how to manage his behaviour.  My partner has never been shaken up by Caspers behaviour before as we usualy know what sets him off and difuse the situation.  I think the sight of Caspers teeth at face level when he was in a mood have brought home how much damage he could do if he was to 'flip'.

Any help or advice?

By the way, he is never allowed out when people are around at home as we wouldn't put Casper or visitors in a situation that may lead to aggression.  Out on the lead he is much admired and petted, loving the attention.

At the moment it sounds like he is ill and his behaviour at present may partly be due to that, so my advice would be to take him to the vet about the lumps first. If everything is OK there then get a referral to a good behaviourist. HTH.

We have seen a behavourist previously with Casper, and we can manage his behaviour normally and understand why he is why he is (very bad early experiences).

He is a very well trained dog, sits, stays, walks to heel and comes when called (as long as there are no rabbits around!).

It was just his pinning my partner against the wall earlier was out of character.  He will growl and be quite confrontational sometimes, but never to this extent, and as I said, a very large well muscled Weimaraner growling at you face to face while you are pinned up by him is quite a frightening experience.

I have got him booked in at the vets on Monday so we will see what the vet has to say about his lumps.

Just to say, a wagging tail is a sign of arousal - but not always happiness.

It sounds like he is in pain, so of course he will be a bit annoyed if anyone manages to touch (even by accident) his head/ear. Personally, I wouldn't have left him until Monday, but then I haven't seen his wounds. It maybe sounds a lot worse than it is.

Hopefully once he has been sorted out and the sores are healed he will go back to being the dog you know.