mentsch1: Those that hold that the kula of Cholov Stam (i.e. relying on governmental oversight instead of a Yid) is invalid, hold that such milk is therefore Cholov Akum and non-kosher. Even if it is really cow’s milk that was milked by someone not Jewish with no Jewish oversight, if one doesn’t accept the C.S./government kula the resulting milk is deemed C.A./non-kosher.
Pashut Halacha from Chazal is that any milk that came without the oversight of a Yid is considered Cholov Akum, and therefore treif, even if it is cow’s milk. Cholov Stam is a kula that you can rely on the government instead of a Yid for the oversight. If you don’t hold that is a valid kula (and many poskim do not, especially in the Chasidic world) then the milk is Cholov Akum/treif even if it is cow’s milk with an OU-D.