A long time ago, men discovered that there was another use for those animals that share the land with them. After hunting them for years, humans discovered that they should not only just consume them for meat. Instead, they should outsource some of the hardwork to these animals, namely, the cow. Hence, the plough was invented. Taking a makeshift cart, they attached it to a ox who they somehow managed to tame. With this the humans made the ox do the work that for so long was back-breaking for the humans.
This period was called the secondary products revolution. Secondary products being the fact that animals can now have another use apart from just their meat. Besides the plough, the female cattle were used for milking as well. It was significant as humans finally discovered something nutritious from an animal. Red meat for all its hype was purely a diet meant for Lions. If humans wanted to survive longer than the Lions, they need something else. And that something else could potentially have been Milk.
Unfortunately, there was a problem. Humans were largely lactose intolerant. Except for the Northern Europeans who possess some kind of immortal digestive system, the rest of the world could not drink milk off the cow directly. In particular were the Chinese folks. The Chinese and Milk did not go together. Yes. We were a race largely dependent on Pigs and Rice. The Chinese like the Negroes did not possess the ability to digest milk and hence when we drank that whitish liquid, we will experience a bloated feeling, flatulence, belching, cramps and a WATERY and EXPLOSIVE DIARRHOEA.
This is why today if you are apprehensive about milk, you can console yourself that this is in fact genetic. Your forefathers would never touch milk with a long stick and so neither should you. Fortunately, mankind are always constantly evolving and adapting to change. If there is something to gain from milk, you can guarantee that humans would make it into such a way that milk can be consumed by everyone. Hence, the creation of Cheese and Yogurt. These products contained lactose that were broken down into simpler sugars. As the result, humans can now benefit from this nutritious cow product without having to endure watery and explosive diarrhoea.
This secondary products revolution is important because it laid the foundation for greater things. As humans can now rely on animals to do most of the 'sai kang', they can put their energies to better use and think of grander plans. This was how civilisation and eventually cities were formed. We must be thankful that the Cows and Oxen were willing to contribute to the rise in the standard of living of mankind. No wonder Cows are regarded as sacred entities in places like India. The cows deserve it.
So if you look at yourself today and wonder how everything around you is so modern and nice, you have to thank the animals for freeing up the human mind to come up with better and nicer structures. After all, we can always depend on the cow to help us in our grand masterplan.