Vets have very little knowledge about purebred dogs. At least not beyond the chart on the wall some where in the office. Some vets do have an interest in a particular breed or two but their knowledge base would come from their own independent study of the breed.
Most local vets are much like a family doctor, or what used to be called a general practitioner. You can't take what they say about what breed your dog is real seriously unless they have some personal experience of their own researching the breed.
Of course 5lbs at two months of age is kind of big but you have to look at other charasteristics as well. If you think your pup looks like a Yorkie and that is all that matters to you then just forget about what the vet said and maybe find a new a new one. |