Hi
I have a 2 year old weimaraner dog, he is a great dog.
but since I got my second dog a vizsla bitch she is now 5 months old he has become very agressive with other dogs mostly males when we are out walking.
Before he would play nicely with other dogs although he would some time get a bit heavy pawed he was never agressive and always stopped when i told him to.

This problem really upsets me as I made a point of mixing him with every dog so this problem would never happen.

Please could anyone give me some advise on this problem.

There are many varied reasons why dogs aggress.  It could possibly be resource guarding - the resource being the Vizsla girlie.  Do you always take them out together?

Yes I do mostly take them out together the only time I don't is when I am trainning my vizsla.

Perhaps then it would be worth seeing if he is any different if you take him on his own for a walk.  It's always a good idea to walk them separately as often as possible anyway. 

Thanks I will give it a go, I will let you know how i get on.

This is an extremely common trait in Weimaraners.  They will, as Sally has said, resource guard "their bitch".  You need to be extremely careful as this tendency will increase especially when the bitch comes into season; obviously you have given thought about what to do with your dogs twice a year if you have an entire male and bitch. 

Hi tohme

My Weimaraner has been neutered, do you think it will still be a problem. Obviously when my vizlsa comes into season she will only be aloud to run in my enclosed garden and  my weimaraner will be walked alone at that time.

do you have any other helpful tips or ideas on how i can stop my weim from being aggressive outside the house?

thanks

Yes it will still be a problem, he may even attempt to mount her (and I've known neutered dogs acheive penetration as well..........)

A neutered dog can still mate an in season bitch and she will likely have a false pregnancy.

Neutering will not prevent your dog or any dog for that matter resource guarding; it has nothing to do with sex necessarily :D

The dog just wants to prevent access to a valuable resource, be that a dog, the owner, the sofa or food by others :D  Dogs are hard wired to do this and no amount of "breeding" has "bred it out"!

The best thing you can do for any dog to prevent incidents is to adopt the same procedure as you would when driving :D :

Observation, anticipation, planning and restraint!  99.9% of all incidents are avoidable if we remain alert to our dogs, the environment and other factors!

HTH

I have not heard of resource guarding, but it makes sense.  I am wondering if this behavior is less liking to occur with two bitches or two dogs?

Do you mean in relationship to each other or generally?

The writer said they the dog had become aggressive.  I just wondered if the owner had gotten another dog instead of a bitch, would that have decreased the chance of the aggressive behavior to other dogs.  Or is it simply, because they are of opposite gender?

Hi
I got a bitch instead of a dog because i though they would become more aggressive with each other and probably pack together when out walking.I hope I haven't made a bad mistake

In general we recommend that owners who have a male Weimaraner get a bitch as a companion and vice versa; as the risks of two males or two females not getting on are much greater.

Thanks for putting my mind at rest, as to me making the right decision on a bitch and a dog together.
I know only to well that it will never be easy with my Weimaraner, it took me 2 years of hard work to get him the way i wanted him to behave as a family pet, some people still find him abit over powering, but this is what I love about him. I really enjoy the challange.
I would love to start agility classes with him as I think he would love it. Do you think he is to old to start agility or can you start at any age.

http://jessejump.co.uk/weimleaguetable.htm

No he is not too old, there is even a special weimy agility league :D  Make sure the club is a good one.