What is a rot and lab dog called?

There isn't a specific term for a "rot and lab dog". It seems like you're combining "rot" (possibly referring to Rottweiler) and "lab" (referring to Labrador Retriever).

If you're asking about a mix of those breeds, it's usually called a Rottweiler Lab Mix or a Lab Rottweiler Mix.

Sometimes, people also use less formal names, like Rottie Lab or Lab Rottie.

It's important to remember that, while the combination of these breeds can be beautiful and loving, every dog is an individual, regardless of their mix.