I have a very strong lurcher who has problems with some dogs and not others. Because he is this way he never goes off the lead and has an extendable lead which is made for much larger dogs than him because he is so strong. She must have had too small a lead for him to break it.
Fortunately he does respond when I shout at him and I always look ahead for other dogs and lock his lead on a short length if I see other dogs. I don't need to muzzle him but I would if he was a bad as your friend's dog.
I think putting him to sleep is a bit extreme. She just needs to be very aware when she goes out with him. If she can't put him on a long lead then she should just use a short one.
Maybe she could ask around at any nearby shelters to see if they would let her exercise him in their compound so he can get some running? That's what we do with Danny and we pay them a small fee for the priviledge.
Danny is a difficult dog when we're out but we have learned about his behaviour and know his body language therefore can control him. And we didn't have to pay anyone to analyse him! he will never change so we adjust to keep on top of it. Your friend needs to do the same.
Also we use a harness for him as it gives us a lot more control over him as he's so fast and strong.
Please advise her not to have him put down..I don't really think it's a good enough excuse.

I agree with the others he needs a head collar and to go back to training. Momo has a real problem with back and white springers. All brought on by a couple of people having them off lead and letting them run circles round us. Which prevented her from having a smell and made her frustrated. Anyway I've been taking her training and if I see a springer in the class I head over and make sure we are next to that dog. I believe it's the only way she's going to be able to get over it.

I really hope your friend can get him sorted out. As it would be a very sad thing for him to be put down just through this.

Midnight: Both my present dog, Tai, and my last dog, Hal, have and had issues with black labradors! Especially in the case of Tai, he is the gentlest, least likely to attack another dog in the world ... but he hates this particular black labrador who comes into our pub, and funnily enough, so did Hal before him.

We thought we had got over this problem, and Tai had accepted that the black lab is a lovely dog (he is) and not going to cause him any hassle, but no, it has started up again but even worse. I actually raised this problem with Shaun Ellis, and he said that it is not uncommon by any means for dogs to attack seemingly very uncharacteristically and out of the blue, black dogs. In the wild, whether with wolves or wild dogs, single colour is exceptionally rare, if not impossible, therefore with some dogs an all-black dog with no relief presents itself as a target ... the very rare occurrence of albino wolves always results in the albino being driven away to fend for itself, almost always resulting in early death. Because Tai is such a sweet-natured and unaggressive dog, this attack is so out of character that I am inclined to accept the theory. It is not as if he is just growling at the black lab, he actually wants to attack it. And the same with Hal, he reacted in exactly the same way to this poor dog, and again this was extremely out of character.

This is my explanation for your friend's dog's behaviour, but as to how to rectify the situation, I am not so sure what to advise. With Tai, we obviously keep him on a very tight lead now in the pub, in case the BL comes in. Out in the woods and fields, when Tai is always off the lead, the problem is far less severe. He is absolutely fine with black labradors unless one growls or attacks him, and then he will stand up for himself with the minimum amount of force. He is a very large dog, and he uses his size to subdue the other dog, never his teeth, which is fine. It is in the enclosed space of the pub, with him on the lead, that we have to be so careful because he is the aggressor, there is no getting away from that fact. I would love the two dogs to go for a walk together, off lead, out in the woods, and I am absolutely sure they would be fine, there may initially be pistols at dawn, but they would sort out their doggy differences, and peace would reign. I don't know if this would apply to your friend's dog, but we find the best thing with Tai is to trust him and trust his instincts. When the black lab comes into the pub, and Tai starts to bark at him, I very calmly stand up and block his view and force him to look at me or at my legs, so that he can't see the lab. I make him shut up, and lie down, and usually that's it, peace is restored. Once the black lab has settled down with his owners, all is well. It is not easy, but I think the best thing your friend can do is to keep the faith with her dog, stay calm, and try and work through this situation, keeping him on the lead and trying what I do with Tai. If the dog cannot see the other dog, and you have got his attention focussed on you, he should calm down. You can then praise him for being a good dog.

Thankyou for all the replies.

I've printed them all off to give to her, so she can try out all suggestions. Thankyou all so much for all the help & advice, I'm sure we'll be able to get through this & they can continue being a happy family when all this is sorted. It might take some time, but we'll get there.

Thankyou all.

We're in Cardiff, South Wales

My 2 get on with virtually every dog but when my sister in law got an all black dog they hated it!!!! and my foster who was the sweetest jack russell i have come across and got on with all dogs turned into a rabid devil when he turned up,she still is like it with her new owner but only with black dogs The lady who i fostered from said its very common because dogs can't read the black dogs facial expressions. So at least she isn't the only one with this problem but it sounds like she needs to sort it out asap.

I like that explanation about the facial expressions, it makes perfect sense. It's a bit tough though if you are a black labrador and keep getting attacked! The problem is I think it can be self-perpetuating in that it would be perfectly understandable for me to tense up when a black dog hoves into view. Tai would then pick up on my stress, and think that there is something to be wary of in black dogs. It is so important that I remain noncholant and relaxed when we meet black dogs, but it is difficult. You want to be alert to any trouble, but at the same time you don't want to cause any!

Wow I have to say this black dog attack thing has to be the weirdest thing I've ever heard. In two years of owning my all black dog I haven't had one dog attack her who wasn't dog aggressive to start with. How odd.

I know, I have never experienced such a thing before I got Hal. With him, it is pure hindsight that I realise of all the dogs he didn't like - and they were very very few - they were always black or single coloured, dark brown or mid brown. Tai is much more "colour-ist" - he definitely has a strong anti-black streak in him. It is most extraordinary, but I really do buy into the inability to read facial expressions. Both Hal and now Tai were really quite myopic. Tai in particular finds it very difficult to see us in a crowd, and will go into a perfect panic when he loses us. He can smell us, but he can't see us, and he freaks. Being myopic, perhaps he has a real job to read the face of a single colour dog. The darker the colour, maybe the harder it is for him to see the dog clearly. It would account for why a dog who really is such a gentle giant, would never ever be aggressive towards another dog, can be seemingly such a pig towards what is a beautiful, gentle, lovely and very confused black labrador !! The poor boy looks so bemused and bewildered whilst this massive hairy wolfy looking monster is barking his head off at him, lungeing and growling all the while.

I think a stable well mannared dog souldnt be attacking a dog for a reason like colour or something
But there are too many dogs who are not stable, have problems one way or another (even eyesight) and the difference of not being able to read what the dog is saying can be enough to cause the dog to react