It takes a lot of space to grow the grain to feed the animals. Plow down some more forests to make more land available for raising grain and for grazing. It affects the quality of water in the surrounding communities. Fish and seafood are also affected by this water pollution in some areas. This hormone, given to cows, is excreted in their milk.
Many humans feed their babies cow's milk formulas, believing it is a good wholesome food.
Then there's all the antibiotics they give the animals to counteract some of the effects of their unhealthy lifestyle. Half the antibiotics used in the U.S. go to farm animals. Not to mention the wear and tear on the milk drinker's immune system, and the destruction of friendly bacteria in the intestines which are nature's B vitamin factories. Speaking of factories, milk cows are forced to make 10 times the normal amount of milk. Yes, of course you drink them when you drink the milk.