Animals first started being used thousands and thousands of years ago when nomadic people started to settle down into agrarian communities. Large beasts of burden were specifically found in Europe, which in turn allowed for a burgeoning population with growing utilization of these beasts of burden. Then the industrial revolution came along and really kick started an incredible optimization of modes of production, which include fully optimizing beasts of burden to create the commodities consumed for life. Populations boomed and the world caught a glimpse of the modernity of immensity and population that we all know today. However, these advances in technology that increased human luxury created a reciprocal phenomenon that in turn increased animal cruelty. The more "natural" and "humane" (I put this in quotes because it is not entirely natural, and not entirely humane either) way of treating the environment and raising animals in the past died out as seen by the symbolic destruction of the remaining Native American cultures by the industrial revolution's railroads branching west.
Animal cruelty has been a constant festering wound on the face of humanity ever since the industrial revolution, not to say it wasn't already a visible sore before the industrial revolution. With this I have laid the framework and context for my future questions on animals and humans in the remaining parts of Animal Ethics.