hi I have a 2 year old male lab who last year sired 2 litters of puppies after he had mated with the female who lives in the same house he attacked her so never used him for mating again he had shown no sign of aggresion before. now in the last week he has attacked 2 of my dogs for no reason 1 a lab female twice he has attacked her, and once my 16 year old mongrel who has dementia . when he attacked the female again today the 16 year old intervened and attacked the lab male but my husband got bit in the process of breaking up the fight he is now kept in a seperate room until we sort out what we are going to do is this usual for a lab male to start being aggresive after they have mated ? he is usually a well behaved dog trying to find out the reasons he is being aggresive they are usually placid dogs as I have had both male and females for years with no problems.
thanks for any help

What do you know about your dog's ancestors?

only that he had a very good pedigree and came from working parents which could not be seen at the time as was told they were not there

And you have bred from him, without knowing his ancesters, and nothing more about him than that he had a "very good pedigree"?  

You bought a puppy without seeing it with its mother? How do you know she wasn't nasty-tempered?

Why wasn't the Mother there! Sounds very suspect.

I think maybe some tests by your vet for any medical reason might be in order.  Have a close look at your home life too.  Is there more tension in the house than usual (from humans and/or dogs)?  Is anything different that might have stressed him out?  Unfortunately I've found from my own bitter experience that keeping dogs separate in a house only leads to more tension for the dogs.  Once you've ruled out all the factors that could have sparked this off it's time to look at the dog itself.  It's a sad thing to realise that some dogs are better off rehomed as an only dog to a loving family and people should never put their own feelings about not wanting to part with them in the way of the dogs' future.  I'm not saying this will be the outcome with yours but please bear this in mind if the need arises.  I hope you soon find the cause and can therefore sort the problem out.

Debs

Hiya,,

Have i read this correctly - you have a 2 yr old entire dog who sired 2 litters last year from a bitch in your house?. Were the litters from the same bitch?
I would have him checked out at the vets - there is no reason for aggression in labradors, unless it came from the breeding line!  As you didn't get to see the parents, it could be down to poor breeding, or even an inherited condition such as HD or even the dreaded PRA.  Any dog in pain is much more likely to 'have a go'

I'm guessing that you didn't have his hips scored? It could even be down to this unfortunately.

Is the bitch coming into season soon, that could add to the tension.

Hope it works out for you.

Ali

Are these puppies out of the same bitch that was 5 years old 2 years ago when the dog was 14 weeks old in February 2005 ?& that you had puppies from 7 months later in September 2005 ?

It's very unusual for a dog, especially one that's been used at stud, to attack a bitch, especially if she's coming into season. Another dog maybe, but not a bitch.

I'm glad that you are not using him to stud again, good breeders should know parents and grandparents from show or working lines and should have met most of a breeding dogs lineage or at least know of them by reputation, plus relevant health and temperament checks to go with that.

But what is done is done, your immediate problem is his behaviour at present.

First and foremost when a dog acts out of character the first thing I would advise is a vet check, he may be in pain which can frequently cause a well behaved dog to lash out, so it is important that he has a very thorough health check.

I know there is a lot of debate about aggression and castration but perhaps castration is needed here again look into this with your vet, as already said it is very unusual for him to attack a bitch so does not appear to be territorial at all.

At a guess I would say he is in some sort of pain, so get that thorough check, and I would not leave him unattended with your other dogs, and perhaps until this is sorted out take it in turns for your dogs to be in seperate rooms divided by a dog gate, for now I would also not leave him unattended with any children either.

I'd insist on a full thyroid panel as well, sudden onset of aggression can be caused by a faulty thyroid.