Does your lease have any provision for pets, or does it specifically prohibit dogs?
Keep in mind that most landlords do not allow pets, because of potential damage, allergy concerns and increase insurance rates that are related to certain breeds. If you were told that pets were not allowed when you signed your lease, and still chose to bring a pet into your dwelling, then your landlord would be well within his rights to evict you.
If there was not anything in the lease about pets, then you would probably have grounds to fight it.
I think all renters should be a landlord for several years before they rent, so they do their best to respect somebody elses property and go the extra step to please them. NOT saying that the other way around would also wouldnt also be helpful!
If pets are not allowed on the property, then the landlord has the right to kick you out. If the contract had stated that no dogs are allowed, the landlord can kick you out of the house due to the violation. Visit a lawyer for more clarification.