Dairy cows produce calves, who are taken away immediately from their moms so that people can drink the milk. The males are usually sold off for veal whilst the heifers are confined to individual sheds/igloos where they are fed a diet very different from their mothers' milk. They are deprived all contact with their mothers. When old enough to breed, they are impregnated (often using what is called in the industry a rape rack) frequently by artificial insemination. Dairy cows are continually kept in calf until their production drops; the average age of a "spent cow" is 5 years, when they are slaughtered for hamburger. Spent cows often are so weak that they are dragged to the kill floor. These cows are called downers. I have seen cows with obvious tumors sold and their flesh sold for human consumption. CAFOs are about $ and the animals suffer.

Humans are the only animals that drink milk from other species. There are many non-dairy alternatives available. Don't be cruel- don't drink milk.