You don't need to know. At least that's what companies like Monsanto and some in the dairy industry are saying. That's because more and more consumers are buying milk that is labeled as hormone-free.
This hormone, recombinant bovine somatotropin and known as rBST or rBGH, is sold as a product called Posilac and stimulates milk production in cows of up to an extra gallon a day. The Food and Drug Administration has said it's safe, and it's being used in about a third of the dairy cattle herds in the United States. Several European countries disagree, however, and have banned it.
With consumers, and many stores like Whole Foods and even Wal-Mart, wanting to buy hormone-free milk, the sales of Posilac are threatened. So Monsanto and its industry mouthpiece, the American Farmers for the Advancement and Conservation of Technology, or Afact, are actively working in several states to ban labels that declare milk to be hormone-free.
An article in Sunday's New York Times titled "Fighting on a Battlefield the Size of a Milk Label" talks about these industry efforts and calls the "grassroots" nature of Afact into question. Oregon Physicians for Social Responsibility is involved in fighting anti-labeling legislation on a national level, and you can download their list of hormone-free dairy producers here. Get a state-by-state breakdown of where current legislative efforts stand by clicking here.