Bovine, simply put, refers to cattle. But when we delve into the realm of animal science, particularly regarding dairy production, the term often intersects with discussions about Bovine Somatotropin (bST). So, What Is A Bovine and how does bST play a role in its life and milk production? Let’s explore.
Bovine Somatotropin (bST), also known as bovine growth hormone, is an animal drug approved by the FDA to boost milk production in dairy cows. It is essentially a synthetic version of the somatotropin hormone naturally produced in cattle. Somatotropin, a protein hormone secreted by the pituitary gland in animals (including humans), plays a vital role in growth, development, and overall health.
The History and Development of bST
Research into bST dates back to the 1930s and 1940s in Russia and England, where scientists discovered that injecting cattle pituitary extracts containing bST could enhance milk production. During World War II, English scientists even explored using pituitary-derived bST to address food shortages by increasing milk yields. However, the mass production of bST only became technically and economically feasible in the 1980s through biotechnology. This biotechnologically derived bST is commonly known as “recombinant” bST or “rbST.” This process offers advantages such as producing a more consistent and purified form of bST.
FDA Approval and Safety Considerations
The FDA meticulously evaluates animal drugs for food-producing animals like bovines, ensuring the safety of the resulting food products (milk and meat) for human consumption. This rigorous process also confirms the drug’s safety for the treated animals and the environment. Furthermore, the drug’s effectiveness must be proven. The FDA approves product labeling with complete directions for safe and effective use. Public documents known as Freedom of Information Summaries, published on the FDA website, provide a comprehensive overview of the information used to determine the drug’s safety, effectiveness, and environmental impact.
Posilac™: A Commercial bST Product
In 1993, the FDA approved a bST product named Posilac™ (sometribove zinc suspension) after a thorough evaluation of its safety and effectiveness. Posilac™ is available for over-the-counter use in dairy cows, starting about two months after calving and continuing until the end of the lactation period. Cows receive subcutaneous injections of Posilac™ every 14 days during this period. A typical lactation period for a cow is approximately 10 months, beginning shortly after calving. Consequently, treated dairy cows generally receive Posilac™ for about eight months annually. Following the 10-month lactation period, producers cease milking the cow, allowing a two-month rest and regeneration period for the mammary gland before the next calving and lactation cycle.
Safety for Human Consumption: Why bST is Not a Concern
A critical factor in the FDA’s determination of the safety of milk and meat from Posilac™-treated cows is the nature of bST itself. bST is a large protein, and like other dietary proteins, it is broken down by digestive enzymes in the gastrointestinal tract and not absorbed intact. These digested protein fragments have no biological activity. Moreover, even if injected directly, somatotropins from lower mammalian species, like bovines, are inactive in humans. Posilac™ has a zero-day withdrawal period, meaning milk and meat are safe for human consumption at any time after treatment. Numerous international health and food safety organizations and national regulatory agencies have affirmed the safety of milk and meat from bST-treated cows.
Safety for Bovines: Addressing Potential Side Effects
Before approving Posilac™, the FDA meticulously analyzed numerous studies to assess its safety for dairy cows. These studies, often conducted under typical farm conditions across the U.S., evaluated the treatment’s effects on various aspects of bovine health, including feed intake, reproductive capabilities, and the health of their offspring. The FDA concluded that Posilac™ is safe for use in healthy dairy cows. Although some increased side effects were observed in treated cows, the FDA deemed them manageable under standard U.S. farming practices. The product labeling clearly identifies potential side effects, enabling dairy farmers to make informed decisions regarding Posilac™ use in their herds. A post-approval monitoring study involving over 1000 dairy cows across 28 U.S. herds further substantiated the product’s safety for the treated animals.
Ongoing Monitoring and Surveillance
As with all FDA-approved drugs, the agency continues to monitor the safety and effectiveness of Posilac™ through ongoing post-approval surveillance and evaluation of all reported adverse drug experiences, ensuring the continued well-being of bovines and the safety of their products.
In conclusion, understanding “what is a bovine” in the context of bST usage reveals a complex system of regulations, safety evaluations, and scientific considerations designed to ensure both animal welfare and the safety of the food supply.
