Blog - Think Tank

False Advertising with the...Truth? Antibiotics, Milk & Animal Science

July 13, 2015
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If you are like me, you’ve probably seen the (relatively) new milk commercials that have the 5 point promise...which is why of course it is the best…and you should buy it.  Now the claims may be true, but what they don’t tell you—It is also true of most of the milk you buy at the grocery store.  Some are pretty self evident—all milk is quality tested to ensure safety, milk comes from cows fed a healthy diet, and it is cold shipped fresh from your local dairy (although this is a little misleading because most milk is pasteurized, processed & put into jugs somewhere other than on the dairy farm).

Now the 2 biggies (potentially most concerning for you as a consumer & interesting scientifically speaking) are the promises that “All milk is tested for antibiotics” and “No artificial growth hormones”.  For the first—all milk commercially sold in the United States is tested for antibiotics. Every single tanker truck load is tested prior to unloading for processing, if antibiotics are found, the entire load of milk is dumped.  

The second refers to the “artificial” compound used treat cows called rBST (recombinant bovine somatotropin) that is derived from bacteria or yeast that have the BST gene from cattle inserted into their genome.  rBST was the first biotechnological  product approved for animal production by the Food and Drug Administration (FDA) in 1993. Most milk in the U.S. is rBST free.  In 2007, only 17.2% of dairy cows in the U.S.  were given rBST—82.8% (~7,558,812 cows) weren’t (

Now the bigger question is should you be concerned about rBST in you milk?  The answer is no, for a few reasons:

  1. Only a minute quantity of BST is naturally present in cow’s milk (.000006% of total milk protein), this level is not affected by rBST treatment. 
  2. Somatotropin is a naturally occurring protein hormone produced and secreted by the pituitary gland of mammals.  All characteristics and properties of rBST are identical to the “natural” BST produced by cows. BST is not active in humans; somatotropin receptors on human cells do not recognize BST.  (
  3. rBST is a protein hormone, which your body treats the same way as it treats the protein in a pork chop or in black beans—it is completely digested in the stomach and small intestine down to the building blocks, amino acids.  

(On a side note—the same type of strategy is used for selling chickens and pork.  The FDA prohibits the use of added hormones in chicken and pork production, so labels saying “no hormones added” are just for marketing purposes.  In fact, if that statement is used it must be followed with "Federal regulations prohibit the use of hormones."

If you want to learn more about this and other exciting topics regarding the science behind breeding, raising and caring for animals check out AGRI 109, Principles of Animal Science this fall!  These classes are GEM scientific ways of knowing courses which count towards 4 of the 7 credits (including the lab credit) required at CWI for an AA or AS degree (see the 2015/2016 CWI catalog, pages 57 & 120