Bovine somatotropin

Bovine somatotropin (abbreviated bST and BST) is a protein hormone produced in the pituitary glands of cattle. It is also called bovine growth hormone, or BGH.

BST can be produced synthetically, using recombinant DNA technology. The resulting product is called recombinant bovine somatotropin (rBST), recombinant bovine growth hormone (rBGH), or artificial growth hormone. It is administered to the cow by injection and used to increase milk production. Currently Monsanto is the only company that markets recombinant bovine somatotropin, under the trade name Posilac.

Physiology

A cow's pituitary gland naturally secretes BST into the bloodstream. Some of it latches on to receptors in the liver, which then produce Insulin-like Growth Factor 1 (IGF-1) which enters the blood as well. These two hormones have many different effects in the body, including increasing the breakdown of fat for energy and helping to prevent mammary cell death. [ [http://www.extension.umn.edu/distribution/livestocksystems/DI6337.html Dairy Research and Bovine Somatotropin ] ] The combination of increased energy from increased fat breakdown and decrease in mammary cell death is thought to be the cause of higher milk production.

Studies have shown that there is no increase in the amount of BST secreted in the milk when a cow is injected with supplemental rBST. However, the studies have been conflicting about whether or not IGF-1 and IGF-2 output increases. The amount of IGF-1 and IGF-2 secreted varies greatly by stage of lactation and whether or not an animal is pregnant; most studies have shown that while these hormones are slightly elevated overall it falls within the normal range of variation.cite journal |author=Collier RJ, Miller MA, McLaughlin CL, Johnson HD, Baile CA |title=Effects of recombinant bovine somatotropin (rbST) and season on plasma and milk insulin-like growth factors I (IGF-I) and II (IGF-II) in lactating dairy cows |journal=Domest. Anim. Endocrinol. |volume= 35|issue= |pages= 16|year=2008 |pmid=18325721 |doi=10.1016/j.domaniend.2008.01.003 |url=http://linkinghub.elsevier.com/retrieve/pii/S0739-7240(08)00006-4]

Posilac

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.cite web | title = Dairy Research and Bovine Somatotropin | url = http://www.extension.umn.edu/distribution/livestocksystems/DI6337.html | publisher = University of Minnesota | last = Crooker | first = BA | coauthors = et al. | year = 1994 | accessdate = 2008-01-16 ] Monsanto developed a recombinant version of BST, brand named Posilac, in 1994,cite web | url = http://www.monsantodairy.com/about/general_info/index.html | title = General information - Posilac | accessdate = 2008-01-16 | year = 2007 | publisher = Monsanto ] which is produced through a genetically engineered "E. coli". A gene that codes for the sequence of amino acids that makes up BST is inserted into the DNA of the E. coli bacterium. The bacteria are then broken up and separated from the rBST and 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 generally 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. [cite web | url = http://www.monsantodairy.com/faqs/fda_rbst.html | title= bST Fact Sheet | last = Barbano | first = D | publisher = Monsanto | accessdate = 2008-01-16 | year = 2007]

It was announced on August 20, 2008, that Elanco Animal Health, a division of Eli Lilly and Company, will pay at least $300 million to buy the rights to Posilac from Monsanto.

Use of Posilac

Posilac prevents mammary cell death in dairy cattle. As such, it does not increase milk production on a day-to-day basis, but rather prevents milk production from decreasing over the long term, thus resulting in higher overall production during a lactation. Because a cow's milk production increases and decreases during her lactation based upon a known curve, application of Posilac can be carefully planned to maximize results.

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 and 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 the benefit of Posilac.

Controversy

Use of rBST is controversial because of its potential effects on animal and human health and the perceived encroachment on small farmers by large corporations.

Animal health

Two meta-analyses have been published on rBST's effects on bovine health.cite journal | author = Dohoo, I. | coauthors = Leslie, K.; Descôteaux, L.; Shewfelt, W. | year = 2003 | title = A meta-analysis review of the effects of recombinant bovine somatotropin | journal = Can J Vet Res | volume = 67 | issue = 4 | pages = 241–251 | url = http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=280708 | accessdate = 2008-01-16 | pmid = 14620860] cite journal |author=Dohoo IR, DesCôteaux L, Leslie K, "et al" |title=A meta-analysis review of the effects of recombinant bovine somatotropin. 2. Effects on animal health, reproductive performance, and culling |journal=Can. J. Vet. Res. |volume=67 |issue=4 |pages=252–64 |year=2003 |pmid=14620861 |doi=] 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 but speculated that it may have been attributable to differences in feeding of treated (underfed) versus untreated (overfed) cows.

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. [citation | title = Report on Animal Welfare Aspects of the Use of Bovine Somatotrophin | url = http://ec.europa.eu/food/fs/sc/scah/out21_en.pdf | format = pdf | date = 1999-03-10 | accessdate = 2008-01-16 | publisher = The Scientific Committee on Animal Health and Animal Welfare, European Union ] 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 recommendations of external committees were that despite not finding a significant health risk to humans, the drug presented a threat to animal health and for this reason could not be sold in Canada.cite web | url = http://www.hc-sc.gc.ca/ahc-asc/media/nr-cp/1999/1999_03_e.html | publisher = Health Canada | title = Health Canada rejects bovine growth hormone in Canada | date = 1999-01-14 | accessdate = 2008-01-16 ]

Human health

According to the FDA, the "overwhelming scientific opinion" is that rBST is safe for human consumption, and that no significant difference exists between milk derived from rBST treated and non rBST treated cows. [cite web | url = http://www.ers.usda.gov/Publications/AIB747/aib74701.pdf))] [cite web | url = http://www.fda.gov/cvm/RBRPTFNL.htm | title = Report on the Food and Drug Administration's Review of the Safety of Recombinant Bovine Somatotropin | accessdate = 2008-07-09 | year = 1999 ] In 1990, an independent panel convened by the National Institute of Health reaffirmed the FDA opinion that milk and meat from cows supplemented with rBST was safe for human consumption [cite web | url = http://ageconsearch.umn.edu/bitstream/28850/1/21010010.pdf))]

Still, various consumer groups have expressed concern over perceived effects from both BST itself, as well as insulin-like growth factor 1 (IGF-1), which is increased by rBST injections. Monsanto has stated that both of these compounds are harmless given the levels found in milk and the effects of pasteurization.cite web | url = http://www.monsantodairy.com/about/human_safety/ifst_rbst1.html | title = Bovine somatotropin (bST) | accessdate = 2008-01-16 | year = 1999-09-01 | publisher = Monsanto | author = Institute of Food Science & Technology ]

Lawsuit against Fox television

Fox television affiliate WTVT/Fox13 in Tampa, Florida was sued by Steve Wilson and Jane Akre, two former employees who were fired in relation to their report on BST. The journalists originally wrote a story in 1996 that covered the potential for human health risks of rBST. The station began publicizing the upcoming broadcast of the story, but after a threatening letter from Monsanto, the station asked for changes to the story. Ultimately, following their refusal to change the story and threats to report the station to the FCC, the journalists were fired. [cite news|url=http://www.accessmylibrary.com/coms2/summary_0286-11004059_ITM|title=Blowing the Whistle On Your Own Station.|date=March 1, 2001|work=Columbia Journalism Review|accessdate=2008-09-10] cite news|url=http://www.sptimes.com/News/081900/TampaBay/Reporter_wins_suit_ov.shtml|title=Reporter wins suit over firing|last=Schweitzer|first=Sarah|date=August 19, 2000 |work=St. Petersburg Times|accessdate=2008-09-10] This story is featured at length in the documentaries The Corporation and Outfoxed.

After a five-week trial which ended August 18, 2000, Akre was awarded $425,000 in damages; Wilson was awarded nothing. The jury found that Fox's actions were in retaliation for Akre's refusal of "a false, distorted, or slanted story", in the words of the jury. The jury did not, however, agree that the station bowed to pressure from Monsanto to alter their reporting.

Fox appealed and prevailed February 14, 2003, when an appeals court issued a ruling reversing the jury. The court's basis was that FCC policies on news agencies reporting the truth are not legally binding; and as such, Fox had no legal requirement to report the truth in a news story.cite news|url=http://www.accessmylibrary.com/coms2/summary_0286-18336366_ITM|title=The media can legally lie|date=December 1, 2004|work=St. Louis Journalism Review|accessdate=2008-09-10] In 2004, Fox filed a $1.7 million counter-suit against Akre and Wilson for trial fees and costs.Fact|date=September 2008

IGF-1

Monsanto's studies show use of rBST in cows increases bovine insulin-like growth factor 1 in milk,cite web | url = http://www.organicconsumers.org/rbgh/0724_monsanto_rbgh.cfm | accessdate = 2008-01-16 | date = 2003-02-11 | title = Dr. Michael Hansen on rBGH & Monsanto's Recent Intimidation Tactics | publisher = Organic Consumers Association | last = Hansen | first = M ] a structure that is identical in cows and humans. [cite journal |author=Fotsis T, Murphy C, Gannon F |title=Nucleotide sequence of the bovine insulin-like growth factor 1 (IGF-1) and its IGF-1A precursor |journal=Nucleic Acids Res. |volume=18 |issue=3 |pages=676 |year=1990 |pmid=2308858|doi=10.1093/nar/18.3.676] Monsanto states that there is no danger of consuming milk or meat from cows treated by BST, and that the only difference between milk from supplemented cattle and unsupplemented cattle is the amount of IGF-1, though even these elevated levels are similar to levels found in milk from untreated cows. Further, the amount of IGF-1 consumed in milk is negligible compared to the amount produced in the body.

Opponents counter that rBST does cause differences aside from the higher rate of IGF-1, most importantly that BST and rBST have a different chain of amino acids which can alter how a protein interacts with the immune system. A Health Canada report on rBST found no "biologically plausible" safety concerns for humans about the sale of rBST in Canada barring immune hypersensitivity that may occur in some individuals. [cite web | url = http://www.hc-sc.gc.ca/dhp-mps/vet/issues-enjeux/rbst-stbr/rep_rcpsc-rap_crmcc_e.html | title = Report of the Royal College of Physicians and Surgeons of Canada Expert Panel on Human safety of rbST | publisher = Health Canada | date = 1999-01-01 | accessdate = 2008-01-16 | author = Royal College of Physicians and Surgeons of Canada ] Studies have found links between serum levels of IGF-1 some medical conditions, including breast, prostate and colorectal cancer, [cite journal |author=Chan JM, Stampfer MJ, Giovannucci E, "et al" |title=Plasma insulin-like growth factor-I and prostate cancer risk: a prospective study |journal=Science |volume=279 |issue=5350 |pages=563–6 |year=1998 |pmid=9438850|doi=10.1126/science.279.5350.563] a higher risk of diabetes and a shorter lifespan in animal studies,cite journal | author = Baur, J.A. | coauthors = Pearson, K.J.; Price, N.L.; Jamieson, H.A.; Lerin, C.; Kalra, A.; Prabhu, V.V.; Allard, J.S.; Lopez-lluch, G.; Lewis, K.; Others, | year = 2006 | title = Resveratrol improves health and survival of mice on a high-calorie diet | journal = Nature | volume = 444 | pages = 337–342 | doi = 10.1038/nature05354 | pmid = 17086191 ] and has been linked to an increased number of twins born to humans. [cite journal |author=Steinman G |title=Mechanisms of twinning: VII. Effect of diet and heredity on the human twinning rate |journal=J Reprod Med |volume=51 |issue=5 |pages=405–10 |year=2006 |pmid=16779988 |doi=]

Regulation

Use of the recombinant supplement has been controversial. While it is used in the United States (though not without reaction), it is banned in Canada, parts of the European Union, Australia and New Zealand.

Regulation inside the United States

In 1993, 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 49 states, all but Michigan. According to Monsanto, approximately one third of dairy cattle in the U.S. are treated with Posilac; approximately 8,000 dairy producers use the product. It is now the top selling dairy cattle pharmaceutical product in the U.S.

Enforcement

The FDA does not require special labels for products produced from cows given rBST but has charged several dairies with "misbranding" their milk as having no hormones, because all milk contains hormones and can not be produced in such a way that it would not contain any hormones. [cite journal | url = http://www.sciencenews.org/articles/20031101/food.asp | title = Hormones in Your Milk | accessdate = 2008-01-29 | last = Raloff | first = J | journal = Science News | volume = 164 | issue = 18 | date = 2003-11-01 | format = Dead link|date=June 2008 – ^{[http://scholar.google.co.uk/scholar?hl=en&lr=&q=author%3ARaloff+intitle%3AHormones+in+Your+Milk&as_publication=%5B%5BScience+News%5D%5D&as_ylo=&as_yhi=&btnG=Search Scholar search]} ] Monsanto sued an independent dairy over their use of a label which pledged to not use artificial growth hormones.cite news | url = http://www.commondreams.org/headlines03/0708-10.htm | title = Oakhurst Sued by Monsanto Over Milk Advertising | last = Wickenheiser | first = M | publisher = Portland Press Herald | accessdate = 2008-01-29 | date = 2003-07-08] The dairy stated that their disagreement was not over the scientific evidence for the safety of Posilac (Monsanto's complaint about the label), but rather they were more interested in marketing milk than a drug. The suit was settled when the dairy agreed to add a qualifying statement to their previous label regarding the lack of difference between milk produced by Posilac-dosed cows and cows that had not received the drug.

Demand for milk without using synthetic hormones has increased 500% in the US since Monsanto introduced their rBST product; organic milk is the fastest growing sector of the organic food market. [cite web | url = http://ers.usda.gov/publications/aib777/aib777c.pdf | title = Recent Growth Patterns in the U.S. Organic Foods Market | last = Dimitri | first = C | coauthors = Greene, C | accessdate = 2008-01-29 | format = pdf | publisher = Economic Research Service ]

Labeling in Pennsylvania

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 was delayed to February 1, 2008 in order to give interested parties more time to submit comments to the state's Department of Agriculture. This policy, had it been implemented, would have prevented consumers from distinguishing between milk from cows treated with rBST and milk from untreated cows. The ban was opposed by several consumer groups, and the state reversed its position before the ban could take effect and adopted the Federal Trade Commission's recommended labeling guidelines instead. [cite news | url = http://www.post-gazette.com/pg/08018/850269-85.stm | title = State reverses on dairy labeling, allows hormone claims | date = 2008-01-18 | accessdate = 2008-01-29 | last = Malloy | first = D | publisher = Pittsburgh Post-Gazette ]

Response from commercial groups

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, and the top 3 grocery retailers in the nation, Wal-Mart, Kroger, and Costco have pledged not to sell such milk in their stores. Specific examples include:

*Winder Farms, a home delivery dairy and grocer in Utah and Nevada, sells rBST free milk.
*Safeway in the northwestern United States stopped buying from dairy farmers that use rBST in January 2007. [cite news
title=Safeway milk free of bovine hormone
url=http://seattlepi.nwsource.com/business/300596_safeway22.html
publisher=Seattle Post-Intelligencer (via AP)
date=2007-01-22
accessdate=2008-04-04] The two Safeway plants produce milk for all of Oregon, Southwest Washington, and parts of northern California. Safeway's plant in San Leandro, CA had already been rBST-free for two years.
*Chipotle Mexican Grill has also announced it will serve rBST-free sour cream at its restaurants.cite web
url=http://www.organicconsumers.org/articles/article_3773.cfm
title=Safeway & Chipotle Chains Dropping Milk & Dairy Derived from Monsanto's Bovine Growth Hormone
last=North
first=R
accessdate=2008-01-29
date=2007-01-10
publisher=Oregon Physicians for Social Responsibility]
*Kroger has banned rBST-derived milk from all its stores (including its subsidiaries such as Ralphs) as of February 2008, [cite web
publisher=Kroger
url=http://www.thekrogerco.com/corpnews/corpnewsinfo_pressreleases_08012007.htm
title=Kroger to complete transition to certified rBST-free milk by early 2008 (press release)
date=2007
accessdate=2008-01-29]
*Publix announced it has been rBST-free since May, 2007. [cite web
url=http://www.publix.com/about/newsroom/NewsReleaseItem.do?newsReleaseItemPK=2476
title=Publix Milk goes rbST-Free (press release)
date=2007-04-30
accessdate=2008-01-29
publisher=Publix]
*Braum's has also issued a press release stating its milk is rBST-free. [cite web
url=http://www.braums.com/whatsnew.asp?id=94
title=Braum's Milk - We Believe in Natural. (press release)
publisher=Braum's
year=2006
accessdate=2008-01-29]
*Starbucks Company has as of January 2008 made all dairy in beverages rBST free. [cite web
url=http://www.starbucks.com/aboutus/pressdesc.asp?id=819
title=Statement and Q&A-Starbucks Completes its Conversion – All U.S. Company-Operated Stores Use Dairy Sourced Without the Use of rBGH
accessdate=2008-04-04
publisher=Starbucks Corporation]
*Wal-Mart and Sam's Club stores featured hormone-free "Great Value" brand milk, but did not label it as such in 2008. [cite news
first=Dawn
last=House
title=Wal-Mart milk hormone-free, but labels are mum
url=http://www.sltrib.com/ci_8687003
publisher=The Salt Lake Tribune
date=2008-03-24
accessdate=2008-04-04]

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 [http://www.nytimes.com/2008/03/09/business/09feed.html] , a pro-rBST advocacy group called Afact has been most active in these lobbying efforts. Afact is made up of both dairy farmers and allied industries and is closely affiliated with Monsanto itself; the group's acronym stands for American Farmers for the Advancement and Conservation of Technology. Though rBST is one of Afact's main concerns, their mission is to prevent "marketers from convincing some consumers to doubt the credibility and safety assurances from of even the most respected food safety agencies and scientific oversight organizations." [http:/www.itisafact.org]

Thus far, a large-scale negative consumer response to Afact's 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 Afact lobbyists in New Jersey, Ohio, Indiana, Kansas, Utah, Missouri and Vermont. So far, however, this effort has been unsuccessful.

Regulation outside the United States

In Japan, Australia, New Zealand, and Canada, rBST is not approved for use. [ [http://onlinejournal.com/artman/publish/article_1447.shtml We're drinking WHAT? U.S. consumers reject milk adulterated with Monsanto's rBST ] ]

The European Union declared the use of rBST as safe in 1990, but in 1993, a moratorium was placed on its sale by all member nations. It was turned into a permanent ban starting from January 1st, 2000. [ [http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31999D0879:EN:HTML European Council Decision of December 17, 1999] ]

Canada's health board, Health Canada, refused to approve rBST for use on Canadian dairies, citing concerns over animal health. The study they had commissioned, however, found "no biologically plausible reason for concern about human safety if rbST were to be approved for sale in Canada. The only exception to this statement is 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 developing an antibody response at low dose (0.1 mg/kg/day) after 14 weeks." [ [http://www.hc-sc.gc.ca/dhp-mps/vet/issues-enjeux/rbst-stbr/rep_rcpsc-rap_crmcc_e.html Executive Summary - Report of the Royal College of Physicians and Surgeons of Canada Expert Panel on Human safety of rbST ] ]

ee also

* Genetic engineering
* Growth hormone treatment
* Recombinant DNA
* List of recombinant proteins

Footnotes

External links

* [http://ec.europa.eu/food/fs/sc/scv/out19_en.html Public Health on "Public Health Aspects of the Use of Bovine Somatotrophin"]
* [http://www.sourcewatch.org/index.php?title=Labeling_Issues%2C_Revolving_Doors%2C_rBGH%2C_Bribery_and_Monsanto Labeling Issues, Revolving Doors, rBGH, Bribery and Monsanto]
* [http://www.sustainabletable.org/issues/rbgh/ Sustainable table article the topic]