Recombinant Bovine Somatotropin and its Role in Dairy Production: A Review

Bovine somatotropin (bST) is a natural metabolic protein hormone produced by the pituitary gland in all cattle and used to increase milk production in dairy cows. Recombinant bovine somatotropins (rbST), that has several amino acids, have been synthesized using recombinant DNA techniques. rBST is administered subcutaneously at day 60 of a cow's lactation cycle when milk production normally begins to decrease and repeated every 14 days. Even though bST has the potential to increase the efficiency of milk production, there is no change in milk composition. In the case of rBST, potentially 10-15% more milk can be obtained from each cow. rBST is biologically inactive in humans and its residues in food products have no physiological effect. Concentration of Insulin-growth factor-I (IGF-1) is no significant difference in bovine growth hormone levels in milk from rBGH-treated and untreated cows. Even if there were a much higher level of bovine growth hormone ingested by humans, our digestive system would break down and inactivate the hormone protein. In addition, the bovine growth hormone does not affect human growth hormone receptors and good management measures should be taken as per manufacturer to ensure a high response in milk yield to bST administration. Thus, the use of rbST to improve productivity within the lactating cow herd allows for a reduction in resource use and environmental impact per unit of milk.