That's as dumb as saying
Hey guys, my 2yo Pitbull attacked my 8 month labrador! I thinks it's cause Pitbulls are known to be agresive! (Don't take it seriously peeps, just an example)
No, breeds have almost nothing to do with this behaviour, it's either the fact you didn't do proper introduction and just placed an ''invader'' in the house and your old dog is protecting his territory.
Maybe your old dog is very high prey drive, and sees smaller dogs like preys.
You never socialized your old dog before bringing a new pup home.
Or maybe your dog was putting the pup in place.
Actually some dog breeds are known to be dog aggresive and are bred for it. So yeah breed does have something to do with dog aggression. If a pit was to attack another dog it might have something to do with the fact it's ancestors were bred to be dog aggresive. I'm not sure about the breeds the OP listed but if the queensland healer, is a breed known to be dog aggresive that might have something to do with it.
I don't know how reliable this website is but here's some info about the breeds Temperament.
"The Australian Cattle Dog should be okay with older, more considerate children,
but can be aggressive and wary around other dogs. These dogs are not really suited around cats unless they have been raised with them from puppy-hood. The Australian Cattle Dog is an intelligent and bold breed, but can be a little too headstrong, which means that they need to be handled assertively and firmly. You will also find that the Australian Cattle Dog has bags of energy and will enjoy all sorts of activities. His suspicious personality and vocal tendencies make him a good watchdog, but also mean that he will often be very wary of strangers."
-http://www.justdogbreeds.com/australian-cattle-dog.html
Unfortunately I don't think it was simply a pester factor. The older dog would not stop. When I snatched up the puppy the other dog was foaming at the mouth and puffing his cheaks and jumping on me to get the pup. I'm working realy hard (with the help of a behaviorist) to retrain the 2 yr old - I just hope it is possible. If it's not I can't ever take him in public for fear he may attack something else. Does anyone know of success stories from a case like this? I sure would like to think there are some.
Do you take him out into public now? He's 2 years old, I'm sure you've brought him out in public before. Has he ever shown signs of aggression during those times?
based on your comments I would consider consulting with a different bahaviorist..
cheers
I agree.