From:  rbST Facts

Bovine somatotropin (bST) is a naturally occurring protein hormone produced in the pituitary glands of all cattle, including those raised according to “organic” standards. Its biological function is to direct energy derived from a cow’s food to meet certain physical needs. These needs include milk production in adult cows and growth in their offspring.

It has long been known that cows with naturally higher levels of bST production in their pituitaries yield higher volumes of milk. It was also established long ago that bST, when extracted from a cow’s pituitary and injected into a low milk-producing cow, would boost the milk production of the second cow.

These experiments also established that the amount of bST found in the milk of a cow that had received supplemental bST did not vary from the range normally found in a non-supplemented cow. This is because the cow does not pass bST into her milk in proportion to the amount that is present in her body. Instead, her body “burns up” the bST to produce increased amounts of milk.

From the biological point of view, this disproportion between the amount of bST in a cow’s body and the amount in her milk is logical. Nature evidently intended that the growth-stimulating elements within bST should enter a calf’s body in safe, regulated amounts. Excessive growth hormone introduced by a heavy bST producer could cause developmental problems in her calf and thereby threaten the survival of the species.

Although the effectiveness of bST in boosting milk production was well established by the 1930s, the amounts that could be extracted were very small and the cost was very high. It therefore remained impractical as a tool for increasing milk production for human consumption.

Impact on Humans

Meanwhile, scientists speculated that the growth-stimulating effects of bST might prove effective as a means of treating growth disorders (including “dwarfism”) in humans. The theory was put to the test in the 1950s. In clinical trials, bST was injected directly into the pituitary and other glands of human children suffering from dwarfism. But the injections had no effect whatsoever and the tests were abandoned as failures.

Scientists eventually established that all growth hormones are species specific – that is, that they only work on their own kind. It would later be established that bST is composed of an amino acid chain that has only 30 percent of its sequence in common with the human amino acid chain. Therefore, growth receptors in the human body cannot recognize bST and it does not trigger a growth response. Like all other proteins, bST is digested harmlessly in the human stomach.

These findings confirm empirical data. All cow’s milk has always contained miniscule amounts of bST, normally less than 10 parts per billion (ppb).* Human beings have been consuming bST since they first domesticated cattle at least 10,000 years ago. There is no scientific evidence that bST has in any way influenced human growth patterns during this period.

* All foods derived from animals contain trace amounts of hormones.

Enter rbST and rbGH

In the 1970s, scientists successfully developed recombinant DNA technologies, enabling them to safely reproduce many natural substances for medical or industrial use. Some of the first beneficiaries of the new science were human diabetics, because human insulin could now be produced in the laboratory.

In recombinant technologies, a small amount of a natural substance like insulin or bST is exposed to natural bacteria under sterile conditions. The bacteria cause the substance to multiply or replicate. In replication, individual cells composing the insulin or bST divide to reproduce exact copies of themselves. Then the replicated substance is heated to a high temperature, which kills all of the bacteria. The remaining insulin or bST is not a synthetic substance; instead, it is an identical copy of the original, as “natural” as what came out of the human or cow donor. Even at the molecular level, scientists cannot distinguish the original substance from the replicated version.

Recombinantly produced human insulin was introduced in 1982. That same year, tests on recombinant bST began. In 1987, recombinant human growth hormone (human somatotropin) was introduced and proved effective in treating growth disorders in human children – confirming that growth hormones are species specific in their effects.

In 1985, the U.S. Food & Drug Administration (FDA) – following exhaustive review – determined that meat and milk derived from cattle given rbST are safe for humans to consume. Specifically in reference to milk, the FDA stated that milk from a cow supplemented with rbST or rbGH “is not different” from that of a non-supplemented cow.

In subsequent investigations, the federal government also determined that rbST is harmless to both animals and the environment. In the next few years, these findings were confirmed in independent reviews and tests conducted by the Congressional Office of Technology Assessment, the American Medical Association, the National Institutes of Health, the Department of Health and Human Services, the General Accounting Office and numerous scientific and medical research institutions representing mainstream scientific opinion.

Controversial Stuff

Nevertheless, proposals to make rbST available for commercial use as a tool for boosting milk production generated a firestorm of criticism from opponents of biotechnology. Although the charges leveled against rbST by these groups and individuals were dismissed by mainstream scientists, they were sufficiently alarming to generate widespread coverage in the news media. As a result, consumers were left confused and uncertain about rbST. The controversy also obliged the FDA to initiate another very prolonged and intensive review of all aspects of rbST use. After nearly a decade of further tests and evaluations, the FDA approved rbST for commercial use in November 1993.

Attempts by rbST foes to force the dairy industry to label products derived from rbST-supplemented cows were blocked by the FDA. Under U.S. food labeling law, the presence of an ingredient or substance may be identified on a package label only when that ingredient or substance changes the food from its natural state. Since bST is found naturally in all milk and since rbST is indistinguishable from bST even at the molecular level, the FDA ruled that milk from supplemented cows is not different from milk produced by non-supplemented cows.

The FDA also intervened to stop attempts by some dairy product manufacturers to voluntarily label their products as “bST free.” Since bST is present in all cow’s milk, these “bST free” labels violated “truth in labeling” provisions of federal law.

Eventually, language declaring that a dairy product was derived from non-supplemented cows was developed that was acceptable to the FDA. It has appeared on some product packages over the years; the FDA requires that it be accompanied by a statement to the effect that supplementation with rbST does not in any way change the milk. Some dairy product manufacturers have continued to apply labeling language that violates FDA guidelines. The FDA and various state governments have pursued some of these violations, and Monsanto Inc. – the only FDA-approved manufacturer of rbST – has filed suit against at least one violator (the suit was later settled out of court).

Since rbST’s introduction, its use has become fairly widespread throughout the U.S. dairy industry. Exact statistics are difficult to obtain; rbST is an FDA-approved product sold legally within the U.S., and as such no one can be compelled to disclose whether they purchase or use it. A 1997 survey by Hoard’s Dairyman, a respected industry magazine, found that 31 percent of U.S. dairy farmers had used rbST in that year. The survey further revealed that these farmers had used rbST on 45 percent of the cows in their herds.

The U.S. Department of Agriculture (USDA) estimated that rbST had boosted total U.S. production of milk by only 1 percent in the year following its introduction. However, by 2004, a 50 percent reduction in the supply of rbST (due to production problems) was sufficient to contribute to a tightening of the total U.S. milk supply – although several other factors played larger roles in causing the shortage.

Some countries – including Canada – as well as the European Union have banned the use of rbST. While biotechnology opponents make much of these bans, it is important to note that neither Canada nor the European Union dispute the scientific findings that rbST is safe and effective to use. They have banned rbST for political reasons. In Canada, for example, milk production is “centrally planned,” with production quotas established by government mandates. Increased milk production due to rbST use would disrupt a system designed to keep supply in balance with demand. In some countries, heavy state subsidization of dairy farmers is designed to keep them in business at levels of production and with milk prices that would otherwise force them to cease operation. The last thing these countries want is increased milk supply due to rbST use – that would drive down the price of milk and force taxpayers to spend even more on farmer subsidies. (U.S. dairy farmers do not receive any state subsidization.) A country’s attitude toward rbST often reflects issues relating to that nation’s system for producing milk, rather than its evaluation of the safety or effectiveness of rbST itself.

How it’s used

rbST is normally administered to a cow via a hypodermic syringe. The injection is usually made in the animal’s hindquarters near the base of the tail. Among other things, the increased amount of bST the injection introduces into her body stimulates the cow to increase her intake of food and water. These are converted into increased amounts of milk by her body.

Many people erroneously assume that once a farmer has decided to supplement his/her cows, rbST is given to all the cows in the herd all of the time. This is not true. rbST is designed to be used in synchronization with the cow’s natural lactation cycle. That cycle begins with very high milk production immediately following the birth of a calf (called freshening). Sometime thereafter, milk production begins to decline and decreases at a fairly steady rate until she goes dry. The average cow produces milk 306 days per year.

rbST is administered to cows just before their lactation cycle begins to go into decline. It has little effect on a cow in the first phase after freshening; the animal is then already at peak production and additional rbST will generally not yield more milk. rbST is designed to prolong higher milk yields later into the lactation cycle.

Generally, if rbST is being used on a farm, only a part of the herd will undergo supplementation at any one time. This is because the pattern of birth in any herd means that normally only a portion of the herd will be in the middle and later phases of lactation when rbST has its greatest impact on milk production. Other members of the herd will be pregnant or recently freshened, while the remaining animals will be drying or dried.

rbST boosts milk production in the average cow by about 10 percent to 15 percent. Higher and lower increases are not unknown; rbST impacts different animals differently.

rbST has been shown to evoke a response in all cows that receive it. However, the range of that response will vary among individual animals. In some cows, the resulting increase in milk production will be considerable. In others, it may be less pronounced. A farmer may decide that, in some animals, the cost of supplementation as well as the cost of the increased food and water the animal consumes may not be offset by the increased milk she yields. But these are specific-case considerations. When evaluated on a total-herd basis, rbST is clearly effective in raising overall milk yields.