rBGH and the (mis)Use of Science

What is rBGH/rBST/POSILAC?

At the center of this controversy is POSILAC, Monsanto’s rBST product. The terms bGH (bovine growth hormone), bST (bovine somatotropine) are often used interchangeably. bST is a protein hormone that is produced naturally in the pituitary gland of a dairy cow. It is one of several hormones that helps to regulate milk production. The term rBST or rBGH (the ‘r’ standing for recombinant) is used to refer to the synthetic bST that is injected into dairy milk cows. This synthetic hormone is created through the use of fermentation technology, as shown in Figure 3 to the left.  These synthetic injections, or supplements as Monsanto prefers to call them, can increase milk production by 10-20% in a dairy cow.

    POSILAC is the rBST product marketed by Monsanto, the only rBST product available. After injection, POSILAC flows to the liver through the blood stream and stimulates the production of an insulin-like growth factor (IGF-1). IGF-1 is also a protein hormone that helps to convert a cow’s feed into milk. In essence, POSILAC increases the efficiency of a cow’s conversion of feed to milk production.

Figure 4: How to Handle POSILAC

How Posilac Is Made

Figure 5: How POSILAC is Made 

Figure 6: An illustration of Posilac Injection Sites