No, no, you have it all wrong!
The real meaning of 'when the cows come home' bringing an end to any ongoing discussion is very simple.
As we all know, a major mechanism for genetic diversification from an extant species is geographical isolation. A group of cows in the earliest centuries of the agricultural revolution and the emergence of cows through domestication and selective breeding attained a higher level of intelligence than we see in modern cows and realised that they were being fooled. The wool was being pulled over their eyes as to the true nature of their surroundings, and the lush fields that sustained them and the humans that tended to their needs had merely created a false reality that simulated their wildest cow-dreams in order to pacify and imprison them, in their own delusion that they were free in luxurious and plentiful grassland, devoid of predators and need, them and use them for milk, and ultimately slaughter them all.
Having attained this level of awareness, The One Cow led a group of cows to a promised Cow Land, called Cowon. Here, they have mutated over time, selectively breeding themselves for intelligence, strength, speed and tastiness (in order to taunt us when judgement day comes to pass). They have evolved in isolation into Supercows, and they plan to return 'Home', to the fields, to free their brethren and imprison and slaughter us, ending the human race and any conversation that happens to be occurring at the time.
