I'm sure this isn't the case most of the time though.
American culture is extremely materialistic and profit oriented.
Most decisions about animal husbandry on the farm are made on the basis of profit rather than consideration of the animal's quality of life. I'm sure that the same is also true in most other parts of the world. I don't know much about dairy farming but have heard that even though cows can be milked for years from one pregnancy that they are made pregnant much more often than that because doing so increases their milk production. Also, even vegetarians need to be careful about rennet in cheese. From what I've heard most cheese in the US today is produced using animal rennet, which is extracted from slaughtered calves.