[thule916]

I have a 4 year old male collie/terrier cross. He looks like a Jack Russell only a little bigger. We have had him since he was 3 months old after his owner gave him up as her partner thoguth he was viscious. We took him on not believing a puppy could be aggressive.

All was fine to begin with and we took him to puppy classes which he did really well in. He was very bright and picked up things easily. Towards the end of the classes though he became a little aggressive with the other dogs in class. I spoke with the trainer about this and she told me that it was nothing to worry about and that he was maturing and finding out his boundaries.

After this he was a great dog in the house and very obedient. He was not so good outside though. Almost over night when out on walks he began chasing other dogs and barking getting more aggressive. We started to use the lead more and he would start fighting violently on the lead to get to the dogs some distance away. I have tried avoidance techniques and getting him to lie down with no success.

I have tried him off the lead, in a controlled situation, with some friends dogs and he would run the length of a field to attack them making me think that it is not nervous aggression. After a short time together after this he will then play normally with the other dogs.

About a year ago I rehomed a female Border Collie and the two get on fine and play well.

More worryingly is that he has started to become occassionally aggressive with myself and partner. This is usually when he is in his basket and at night. He will bare his teeth if we approach and afterwards look at us as if he doesnt know what has happened. He will walk outside to his kennel with his tail between his legs making me believe it may be nervous aggression. Very occassionally he has bitten me when I have been stroking him normally and has given me no warning.

He is normally a well behaved, playful, obedient and loving dog but changes completely when other dogs are near or lately for no apparent reason. I have spoken to the vet and trainers but so far nothing has worked.

He is never allowed near children but something needs to be done before the inevitable will have to happen.

Any advice graetfully received.

[Lara's mom]

Have you taken the dog to the vet to rule out any physical issues that may be causing the aggression?

What do you know about the first three months of the puppy's life before you adopted him?

[thule916]

I have spoken to the vet a couple of times but they seem to be of the opinion that some dogs are just naturally more aggressive. They have checked him but no thorough tests. I dont think it is thyroid problems as he has none of the other symptoms and he is a small dog.

I have always wandered about his early months before he came to us. I know his owner doted on him and treated him really well however Im not so sure of her partner as it was clear he didnt like the dog, and I think resented how much attention his partner was giving the puppy. Some people are very strange.

[Lara's mom]

I'm just wondering if there isn't some sort of neurological problem. You mentioned that the dog lashes out and then doesn't really seem to be aware of it. I'd suggest getting some tests done.

[Yogi]

Originally Posted by Lara's mom

I'm just wondering if there isn't some sort of neurological problem. You mentioned that the dog lashes out and then doesn't really seem to be aware of it. I'd suggest getting some tests done.

I am with Lara's mom on this. A head injury to a puppy wherein a tumor could have developed will take some times years before it grows to the point that it can cause serious problems for the dog. Pressure being put on the brain or nerve ends from a growing tumor can cause the dog to flare up, sometimes for no reason to you but the dog is in pain that in most cases cannot be seen. It can create behavioral issues, such as what you are seeing. There are several different types of aggression so for the vet to state that some dogs are just more aggressive than others really offers no truth unless they stipulated one or the other. Fear aggression, bit aggression etc are not the same. For a dog to just randomly go on the offensive and attack one minute then the next be calm as if nothing happened would imply neurological issues. Good luck.

[Todd]

I agree as well. Isn't normal for him to be extremely aggressive one minute and fine the next.

If testing ends up coming out negative there are obviously things you can do such as distraction methods on walks transitioning into eventual controlled situations and further, as well as you establishing yourself as the alpha to control him and stop his aggressive behavior not only towards other dogs but towards yourself. For the time being though, I'd have some tests done. Keep us updated on the results and if they are negative I'm sure we'd all be happy to provide you with further advice.

[thule916]

Thank you for the replies. I am going to get a trainer in to the house next week to see if there is anything obvious I'm missing. If they cannot see any reason for the aggression then I will go back to the vet. I have seen about 5 different vets however and they have all dismissed any physical problems, I will be a bit more assertive this time.

Many Thanks and I will let you know.

[Yogi]

Originally Posted by thule916

Thank you for the replies. I am going to get a trainer in to the house next week to see if there is anything obvious I'm missing. If they cannot see any reason for the aggression then I will go back to the vet. I have seen about 5 different vets however and they have all dismissed any physical problems, I will be a bit more assertive this time.

Many Thanks and I will let you know.

Please remember that neurological is not physical..

[Lara's mom]

You will have to see a neurological specialist. Ask your vet to refer you.