Originally Posted by
Shelley
I would be checking for a retained foreign body in his stomach, he could have swallowed something while being boarded. The red tinge to his vomitus could be stomach irritation from either the medications or a foreign body. X rays would help diagnose this, except some items are not visible on x rays, so be mindful of that. You are doing what I would do for empty stomach syndrome, but since that was not an issue before, I doubt that is the issue now.
Have you called the boarding facility to ask if they noticed him off, or if he ate something? Or is any other dogs have been ill since that time?
In my experience, a dog that is vomiting regularly, is not well, Labradors are well known for being stoic, so they act normal even if they aren't. This could be a host of things, from what has been mentioned, to an abdominal mass, to cancer, etc... I would start with a complete blood panel, and an abdominal x ray, and move on from there. Good wishes