Agressive English Mastiff - Help!!!

[JD]

Help!!!!

I have a 17 month old, male, english mastiff who is starting to be very agressive towards people.  Just last week we took him to the vet and his hackles stood up, and he jumped at the vet tech that was petting him. This wasn't the first time he has done this.  At first we thought it was agression towards males (humans) strangers, but it seems to be all strangers.  Has anybody had anything like this happen, and what did you do to change his behavior??

[Leah-n-boy-os]

A little more history will help.

Is he Fixed, or still Intact??

Is this a rescue/adoption circumstance, or have you gotten this pup directly from a breeder?

If a breeder pup, what does your breeder say? What were the history  on thelines used?

If it's a rescue, any background data from the rescue/pound?

Has the Vet done a full blood panel/tox screening? SOmetimes, when there is a medical issue, it can be detected by an increase in agression/dominanace behavior.

Please respond, give us a bit more detail/background info, and I'm sure all the gang will chime in with some good suggestions.

My main suggestion *right now* is to immediately begin NILF training. (Nothing-In-Life-Free) If you do a forum search, you'll be able to bring up some great resources for that program.

[doggylover]

I have to second Leah's post.  A ton more information is needed to find out what the problem is.  How long have you had the dog?  Did you properly socialize him?  What do you do in terms of daily training?
Coming to the board with this kind of post, so limited in info and over a huge issue is sort of like calling a therapist and saying, 'my kid just stole a car, why did he do that?'.  Not much we can do to help... 

[greek4]

I am still working with my 2 year old female OEM on fear aggression toward strangers.  Here are the steps I took.

--He needs to know his name, so work through the steps of getting him to make eye contact with you when you say his name.  Treat freely.  This teaches him to look to you to get his cues for behavior

--Once he looks to you when he is unsure, you can start added a second behavior, such as sit.  During this time come up with a word to use when you want him to greet someone nicely.  Don't forget he will expect a treat from that stranger for his trick.

--With Maia should bark at people on walks.  To cure this I had tons of treats, when I would see someone I would say "Maia, (she would make eye contact and get a treat) look at that nice lady/man."  She would look then look to me and get a treat.  I had to be alert.

--We then moved up to people approaching, I started with people I know who she has meet only once or twice, then I moved to dog friendly strangers.

--She is still weary of strangers and we go through the steps but she no longer barks or lunges.  She has learned that I am there and I will let her know if she needs to be scared. 

I think Maia will always be weary of strangers unlike Rocco who loves the world.

[smsmith]

I would like to know how much exercise your Mastiff gets. 

[CujoandShamus]

Is it all strangers or just certain ones. I had a shepard mix that just got vibes about people and would bare her teeth if she didn't like the vibe, I would listen to her cues to whether I would trust that person or not. She didn't dislike everyone just certain people.