An Update on rBST – Human Safety and Animal Efficiency and Welfare

Recombinant bovine somatotropin (rbST), the first recombinant protein approved for use in production animals, has received unprecedented scrutiny. In the US this included the traditional evaluation by FDA as well as public hearings, science evaluations and legislative reviews (Bauman, 1992). It has been 20 years since the introduction of rbST ( POSILAC ®) into the dairy industry of several countries, and to date in the US an estimated 35 million dairy cows have received Posilac supplements, the commercial formulation of rbST (personal communication, R. Cady, Elanco).