From what I've read (limited though it may be), it seems that liver shunt, by its very nature, would present outward manifestations. The elevated ammonia levels display themselves in behaviors such as head pressing, walking in circles, lethargy, excessive drooling, vomiting,diahrrea , seizures, disorientation, lack of weight gain in puppies and a general lack of vigor (I'm sure I omitted some symptoms). With all these outward clues, why do most feel it necessary to test every single dog, even those asymptomatic ones? Is it more a peace of mind issue or are there valid medical reasons? With the numbers stated here of liver shunt in Yorkies (36 times the incidence of all breeds combined), it seems that no bloodline is 'safe' and that the problem is within the entire breed or else the numbers are skewed by increased awareness and testing among Yorkie owners. Also, I haven't seen where it has been concluded that liver shunt is an inherited trait (though it is only common sense to not breed a 'sickly' dog) so doesn't testing healthy breeding dogs lead to a false sense of security? I'm not trying to re-start a debate, only posing some questions based on the info I have.
