Is a pledge from dairy farms not to use recombinant bovine growth hormone ( rBGH) sufficient? We look at the ramifications of rBGH use — for. You've probably seen “rBGH-free” on a label or two, but do you have any idea what. rBGH is a genetically engineered variant of the natural growth hormone produced by cows. Look for labels on dairy products such as: “rBGH-Free,” “rBST-Free,” “Produced. FDA rBST labeling guidelines state, "FDA is concerned that the term 'rbST free' may imply a compositional difference between milk from treated and untreated.