[yorkietalkjilly]

Dogs display this type of behavior for a reason and your mom will need to find out the reason. Any sudden aggression needs a vet and if that vet found nothing, I believe I would get a second opinion as the aggression began so soon after the shots. Usually sudden aggression shows up in dogs that are ill, injured, fearful, dominant, frustrated or possessive about their food, people or things. If this is not a result of an illness/pain reaction from the vax or another medical condition just starting to get symptomatic, the dog might be stressed out by other animals bullying, lack of strong leadership, too much structure or bullying by a person or persons, totally frustrated by a lifestyle very inconsistent with his nature, though this instance is pretty rare when there is a strong leader. But I believe I would want to get a second vet to check out the vaccination connection and get a full lab workup, x-rays, etc., to rule out any medical situation and then start to assess what else of the above could be causing this. If it's not medical, more than likely it's been building for a while and the dog has been sending a lot of ignored signals and finally he had to go ballistic to get his message out. So the root of the problem needs to be addressed.