Your pup needs further testing as soon as possible. The longer you wait, the more chance your puppy could crash from a diseased liver. This is a very serious issue that needs medical attention (an internal medicine specialist). Different vets have different protocols about what tests to do in what order. The bile acids test will show how well the liver is functioning. The ultrasound is a way to see problems in the abdomen. Sometimes shunts can be seen on ultrasound and sometimes they can't be. So a perfect ultrasound doesn't not mean there isn't a liver problem. Perfect bile acids mean there is almost certainly a not a liver shunt present. That said, the vet may want to move right ahead into diagnostics because the symptoms your pup is presenting with do strongly indicate that the liver is not functioning very well. This is supported by the fact that the L/D is helping so much.
It's time for a specialist.
__________________ Crystal  , Ellie May (RIP)  , Rylee Finnegan  , and Gracie Boo🐶 |