I see a video like this as proof that evolution, is indeed true and affected by the survival of the some genes. In this case, the natural selection factor of the equation is substituted with the manual selection of the parents by humans.
In a way, this shows that overtime, animals do evolve and we can roughly select certain traits to be passed on. The motivations for breeding this cow are certainly monetary, but I'm sure that there's a lot to learn from in regards to to genetics, and evolution.
What I like about this example, which is essentially an experiment, is that it shortens the evolution process from thousands of years to within a human lifetime. Selective breeding is pretty much manual evolution. Doesn't mean I agree with it, but it clearly shows that the concept of evolution is not just an idea or a theory but actually fact.