Help needed with dominant dog please?

[Tangaroo]

My mum has a mini schnauzer dog who is 6 years old. She also has a terrrier X schnauzer bitch which is 7 yrs. The dog is actually a real wimp but when he meets other dogs he seems to use attack as the best form of defence!
I lost my dog on friday (she was 14yrs old) and one day i would like to rescue another dog.
Problem is, i spend a lot of time at my mums cos the horses live there and naturally my dog would come with me.
I would either have a puppy or a young bitch which is more likely to be timid than bolshy!
I worry that when i introduced it to mothers dogs, the male would attack her. He constantly hounds them and stands over them in an agressive manner and will actually attack them.
If the dog has a go back he will back off and leave them alone but obviously introducing a new young worried dog to this environment is not great and i wouldnt want to terrify the new dog.
How can we train the dog to accept others. Should he be muzzled when he meets new dogs in his own environment until he accepts them ? Should we tell him off if he goes for them?
Mum has been looking for an animal behaviourist to help but not yet found one, we are in Dorset.
Hope someone has some ideas cos i will not get another dog while he behaves like this which means my house will be empty for a long time!
Any ideas?

 

[CAYLA]

If he backs down when another dog retaliates, then he will surely back down if you do the same, for example if you are getting a puppy, the puppy will be to young to fend for it's self and you obs don't want it scarred by your mums dogs, so you step in and reprimand him, you/your mum are more of a pack leader than any dog and he should respect your presence, if he begins to show any aggression step in and push him away and send him away from your area, and tell him NO in your most aggressive voice

It is natural for him to tell the pupp of for pestering, so like wise make sure the puppy does not over do it, if u stay at your mams often it may be wise to crate train the puppy so the older dogs can have time out and get used to a quiet sleepy puppy as well as a playfull over the top puppy

It's always best to introduce them away from his territory, so take them for a walk first, allow them to see and walk along side one another before taking them back home, in doing this, they are getting used to the smell of one another in a neuteral environment and it will tire the puppy out, therfor it's less likely to run and bound all over him as they naturally do on introduction.
They show more aggression when on a lead to strange dogs, you may be suprised and he may accept her pretty quickly.