Bovine somatotropin (abbreviated bST and BST), or BGH, is a peptide hormone produced by the cow's pituitary gland.[1] Like other hormones, it is produced in small quantities and is used in regulating metabolic processes.[1] Since 1994 it has been possible to synthesize the hormone using recombinant DNA technology to create recombinant bovine somatotropin (rBST), recombinant bovine growth hormone (rBGH), or artificial growth hormone. Monsanto was the first to develop the technology and marketed it as "Posilac" - a brand now owned by Elanco Animal Health, a division of Eli Lilly and Company.
The United States is the only developed nation to permit humans to drink milk from cows given artificial growth hormone.[2] Posilac was banned from use in Canada, Australia, New Zealand, Japan and all European Union countries (currently numbering 27), by 2000 or earlier.
In the United States, public opinion has caused a number of products and retailers to become rBST-free.[3][4][5][6]
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In 1937, the administration of BST was shown to increase the milk yield in lactating cows by preventing mammary cell death in dairy cattle. Until the 1980s, there was very limited use of the compound in agriculture as the sole source of the hormone was from bovine cadavers. During this time, the knowledge of the structure and function of the hormone increased.[7] Monsanto developed a recombinant version of BST, brand-named Posilac, in 1994,[8] which is produced through a genetically engineered E. coli. A gene that codes for the sequence of amino acids that make up BST is inserted into the DNA of the E. coli bacterium. The bacteria are then broken up and separated from the rBST, which is purified to produce the injectable hormone. Growth hormones associated with injections given to dairy cows to increase milk production are known under an assortment of terms, but these terms, in general, refer to the Monsanto product. The Monsanto fact sheet on its proprietary product states that, when injected into dairy cattle, the product can increase milk production by an average of more than 10% over the span of 300 days.[9]
A 2007 USDA Dairy Survey estimated rBGH use at 15.2% of operations and 17.2% of cows.[10]
An average dairy cow begins her lactation with a moderate daily level of milk production. This daily output increases until, at about 70 days into the lactation, production peaks. From that time until the cow is dry, production slowly decreases. This increase and decrease in production is partially caused by the count of milk-producing cells in the udder. Cell counts begin at a moderate number, increase during the first part of the lactation, then decrease as the lactation proceeds. Once lost, these cells generally do not regrow until the next lactation.
To apply Posilac for maximum effect, farmers are recommended to make the first Posilac application about 50 days into the cow's lactation, just before she peaks. The Posilac then sustains already-present mammary cells, limiting the rate of production decrease after production peaks. After the peak, production declines with or without application of Posilac, but declines more slowly with Posilac than without. This decrease in the rate of production decline permits dairy cows to produce more milk over the span of a lactation - at its best, this will be seen by seven to eight more pounds of milk being produced per day than would be produced without Posilac.
FDA rBST labeling guidelines state, "FDA is concerned that the term 'rbST free' may imply a compositional difference between milk from treated and untreated cows rather than a difference in the way the milk is produced. Without proper context, such statements could be misleading. Such unqualified statements may imply that milk from untreated cows is safer or of higher quality than milk from treated cows. Such an implication would be false and misleading".[2]
In an article by Tom Laskawy from Grist "GOGREEN", he summarized: On September 30, 2010, a U.S. court of appeal found based on studies presented that there is a "compositional difference" between milk from rBSG-treated cows and untreated milk. The court found that studies have shown that rBST milk has: increased levels of the hormone IGF-1; lower nutritional quality when produced at certain points in the cow's lactation cycle; and more somatic cell counts, which may "make the milk turn sour more quickly."[2] While there is a slight increase in IGF-I, IGF-II does not increase when cows are treated with rBST.[1]
Further, the FDA's concern only regards usual compositional differences, and not the risks typically associated with artificial manipulation of natural processes. This statement of concern may imply that such risks do not exist, and could therefore be considered to be "false and misleading" in itself.
Part of the controversy in the use of BST is concerns over potential effects on animal health.
Two meta-analyses have been published on rBST's effects on bovine health.[11][12] Findings indicated an average increase in milk output ranging from 11%-16%, a nearly 25% increase in the risk of clinical mastitis, a 40% reduction in fertility and 55% increased risk of developing clinical signs of lameness. The same study reported a decrease in body condition score for cows treated with rBST even though there was an increase in their dry matter intake.
In 1994 a European Union scientific commission was asked to report on the incidence of mastitis and other disorders in dairy cows and on other aspects of the welfare of dairy cows.[13] The commission's statement, subsequently adopted by the European Union, stated that the use of rBST substantially increased health problems with cows, including foot problems, mastitis and injection site reactions, impinged on the welfare of the animals and caused reproductive disorders. The report concluded that, on the basis of the health and welfare of the animals, rBST should not be used. Health Canada prohibited the sale of rBST in 1999; the external committees found that, although there was no significant health risk to humans, the drug presents a threat to animal health, and, for this reason, cannot be sold in Canada.[14]
Human health concerns centre around three areas:
The Food and Drug Administration, World Health Organization, American Medical Association, American Dietetics Association, and the National Institute of Health have independently confirmed that dairy products and meat from BST treated cows is safe for human consumption.[1]
Oral consumption: The overall composition of the milk including the fat, protein and lactose content are not altered substantially by the use of rBST in dairy cows. The milk may have a slight change in fat content within the first few weeks of rBST treatment as the cow is allowed to adjust their metabolism and feed intake. The changes in the fat content have been shown to be temporary. The composition of the milk has been examined in more than 200 different rBST treated milk experiments. Natural variation within milk is normal with or without rBST treatment in cows. This is due to genetics, location, feed, age and other environmental factors. The fat content within milk is of high concern due to the nutritional value of the milk changing with fat content. The fat content can also change the flavor of the milk. Cows that are in negative energy balance can have longer chained unsaturated fats which is similar to the fats found in rBST treated cow's milk. Protein in milk content has also been studied and was shown to have no apparent change in rBST treated cows. Nutritionally important minerals that are normally in milk were also unaltered within rBST cow's milk. These mineral studies also showed no significant change in vitamin content. Freezing point, pH, thermal properties, and other manufacturing characteristics of milk was shown to be the same in rBST milk and non-rBST treated milk.[15] Insulin-like growth factor(IGF), normally occurs in bovine and human milk. The rBST treated cows were shown to have an increased level of IGF within its milk content. This increase was shown to be no more than the amount of IGF in early-lactation untreated cows or in the rBST content of human milk. It has also been shown that IGF administered orally has no effect on the organism which ingested it.{Citation needed because this was inserted by a lobbyist, advocating the usage of growth hormone on dairy cows|date=October 2011}} This is because IGF is denatured within the stomach.[15] IGF is produced by the cow in response to BGH injections,[16] and it is this hormone which increases growth and milk production. Bovine and porcine IGF-I are identical to human IGF-I, while IGF-II differs among animal species.[17]
Injected IGF: Neither IGF-1 or IGF-2 are absorbed by the stomach or intestine after ingestion.[15] Injected or naturally occurring IGF serum levels plays a role in the formation of new tumours [18][19] [20] and increased levels of IGF-1 may be linked to increased risk of breast, colon, and prostate cancer. [21] [22] However IGF is involved in many biological processes so it is not possible to assign a clear-cut cause and effect relationship. IGF-1 is not denatured by pasteurisation, so consumption of milk from rBST treated dairy cows will increase the daily oral intake of IGF-I, but serum levels will not be effected due to the denaturing effect within the stomach.[15]
Further association of serum IGF levels with breast cancer was provided by a 20-year epidemiological study begun in 1976, which was published in 1997.[23]
In 1997, Steve Wilson and Jane Akre were terminated by television station WTVT, a FOX affiliate in Tampa, Florida. They filed suit, claiming the termination was due to their involvement in an investigative report criticizing Monsanto's use of rBGH, which the station did not air. Wilson and Akre claimed the station had engaged in "news distortion" under pressure from Monsanto. The lawyers from Monsanto had previously threatened WTVT, warning them that negative consequences would occur in the case that the original story would be published. Akre stated that she and Wilson were fired after 83 rewrites over 8 months.[24] WTVT later aired an edited report, which included responses from Monsanto, while replacing the word "cancer" with "negative health implications" throughout the original. WTVT ultimately won the suit, and the plaintiff's claims were dismissed. WTVT won the case because Wilson and Akre did not have whistle-blower status. The reason they did not have whistle-blower status is because it is legal to report false news.
Use of the recombinant supplement has been controversial. While use is legal in the United States (though not without reaction) and 1 other industrialized nation (Mexico), its use is banned in Canada, Japan, the European Union, Australia and New Zealand. Its commercial use is legal in 19 other countries: Brazil, Chile, Colombia, Costa Rica, Ecuador, Egypt, Guatemala, Honduras, Jamaica, Lebanon, Mexico, Panama, Pakistan, Paraguay, Peru, Salvador, South Africa, South Korea, Uruguay and Venezuela.[25] In Canada, bulk milk products from the United States that have been produced with rBST are still allowed to be sold and used in food manufacture (cheese, yogurt etc.). In the EU, dairy products from the US are banned from import.
In Japan, Australia, New Zealand, and Canada, rBST is not approved for use.[26]
In 1990, The European Union placed a moratorium on its sale by all member nations. It was turned into a permanent ban starting from January 1, 2000.[27] An in-depth report published in 1999 analysed in detail the various human health risks associated with rBST.[28]
Canada's health board, Health Canada, refused to approve rBST for use on Canadian dairies, citing concerns over animal health.[14] The study found the occurrence of an antibody reaction, possible hypersensitivity, in a subchronic (90-day) study of rbST oral toxicity in rats that resulted in one test animal's developing an antibody response at low dose (0.1 mg/kg/day) after 14 weeks." However, the board stated that, with the exception of concerns raised regarding hypersensitivity, "the panel finds no biologically plausible reason for concern about human safety if rBST were to be approved for sale in Canada."[29]
The Codex Alimentarius Commission, a United Nations body that sets international food standards, has to date refused to approve rBST as safe. The Codex Alimentarius does not have authority to ban or approve the hormone - but its decisions are regarded as a standard and approval by the Codex would have allowed exporting countries to challenge countries with a ban on rBGH before the WTO.[30]
In 1995, the product was approved for use in the U.S. by the FDA, and its use began in 1994. The product is now sold in all 50 states.
The Food and Drug Administration stated that food products made from rBST treated cows are safe for human consumption, and no significant difference exists between milk derived from rBST-treated and non-rBST-treated cows.[31] The FDA found BGH to be biologically inactive when consumed by humans and found no biological distinction between rBST and BST.[31] In 1990, an independent panel convened by the National Institute of Health supported the FDA opinion that milk and meat from cows supplemented with rBST is safe for human consumption.[32]
The FDA does not require special labels for products produced from cows given rBST but has charged several dairies with "misbranding" its milk as having no hormones, because all milk contains hormones and cannot be produced in such a way that it would not contain any hormones.[33] Monsanto sued Oakhurst Dairy of Maine over its use of a label which pledged to not use artificial growth hormones.[34] The dairy stated that its disagreement was not over the scientific evidence for the safety of rBST (Monsanto's complaint about the label), but "We're in the business of marketing milk, not Monsanto's drugs." The suit was settled when the dairy agreed to add a qualifying statement to its label: "FDA states: No significant difference in milk from cows treated with artificial growth hormones." The FDA recommends this additional labeling but does not require it.[34][35] The settlement itself caused much controversy, with anti-rBST advocates claiming that Oakhurst had capitulated in response to intimidation by a larger corporation and others claiming that Oakhurst's milk labels were in and of themselves using misleading scare tactics that deserved legal and legislative response.
In 2009 the Kansas Legislature passed a bill that would have required dairies that did not use rBGH to print disclaimers on their labels that stated, “The Food and Drug Administration has determined there are no significant differences between milk from cows that receive injections of the artificial hormone and milk from those that do not.” The bill was vetoed in the last days of the 2009 legislative session by then-Governor Kathleen Sibelius. The legislature removed the labeling language and passed the bill without the provision. [36]
In 2007, the U.S. state of Pennsylvania adopted a regulation that would have banned the practice of labeling milk as derived from cows not treated with rBST. This prohibition was to go into effect January 1, 2008, but after the comment period the guidleines were adjusted to only ban "rBST-free" claims and instead allow claims that farmers had pledged not to use rBST and accompany such claims with a disclaimer such as, "No significant difference has been shown between milk derived from rbST-treated and non-rbST-treated cows."[37]
Several milk purchasers and resellers have elected not to purchase milk produced with rBST. The nation's largest dairy processor, Dean Foods, no longer sells milk from rBST-treated cows though an email from Dean Foods received by a consumer on September 23, 2010, states, "At Dean Foods, we believe that our dairy producers have the right to produce safe, high-quality milk using any approved and available technology..." which would include Artificial Growth Hormones or rBST/rBGH. The top 3 grocery retailers in the nation, Wal-Mart, Kroger, and Costco have pledged not to sell such milk in its stores. Specific examples include:
Monsanto has responded to this trend by lobbying state governments to ban the practice of distinguishing between milk from farms pledged not to use rBST and those that do. According to The New York Times,[44] a pro-rBST advocacy group called Afact has been most active in these lobbying efforts.
Thus far, a large-scale negative response to legislative and regulatory efforts has kept state regulators from pushing through strictures that would ban hormone-free milk labels, though several politicians have tried, including Pennsylvania's (see the Pennsylvania section above) agriculture secretary Dick Wolff, who tried to ban rBST-free milk on the grounds that it would alleviate consumer confusion. Proposed labeling changes have been floated by lobbyists in New Jersey, Ohio, Indiana, Kansas, Utah, Missouri and Vermont. So far, however, this effort has been unsuccessful.