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September 6, 1991

To: Board of Health

Subject: The Licensing and Use of Bovine Growth Hormone (BGH)

Origin: Board of Health, July 10, 1991, c34hlth91119:541


1. That, until its concerns about the drug and the evaluation process have been adequately addressed, the Board of Health oppose the licensing and use of Bovine Growth Hormone (BGH).

2. That the Board of Health communicate the concerns raised in this report to: Health and Welfare Canada, Agriculture Canada, the Ontario Ministry of Agriculture and Food, the Ontario Ministry of Health, the Dairy Bureau of Canada, and the Ontario Milk Marketing Board.

3. That the Food Policy Council report back to the Board of Health when responses have been received.


Following communication from the Downtown and Eastern Health Area Community Health Boards, and addresses to the Board of Health at its July 10, 1991 meeting, the Board of Health requested that the Food Policy Council, in consultation with the Medical Officer of Health, prepare a report on the licensing and use of Bovine Growth Hormone (BGH, also known as Bovine Somatotropin (BST).

Four major drug companies have been developing synthetic analogues of naturally accruing Bovine Growth Hormone for over a decade (1). Results of the first clinical trials on test cows were published in 1985. Claims were made of greatly increased milk production resulting from injection of BGH. Producers of the drug hoped to have the product on the market by 1989, but opposition by dairy processors, some farm organizations and consumers, and delayed delivery to Health and Welfare Canada of the required data, have slowed the process of licensing the drug.


A review of the literature on BGH, covering human safety, animal health, economic benefits, ethics, and socio-economic impacts, reveals that many questions remain to be answered. Research performed to date had identified a number of potential benefits of using BGH, but not all relevant aspects of licensing and use have been addressed by proponents. The key unresolved issues are identified below.


1. Will there actually be any increased milk yield, associated with BGH use, on the average dairy farm?

Reports after the first trials in 1985 suggested that milk production could be increased by up to 30% per cow for the entire lactation period (2). The current consensus of the companies producing the drug, however, is that a 10-25% increase can be expected (3). There is some evidence that many cows will not respond significantly to BGH injections (4). The history of new technology introduction in agriculture suggests that the actual benefits for a typical operation are almost always significantly lower that research trials would indicate, because the real conditions of typical farms are rarely replicated in research trials (5). Given that BGH trials have used conventional research paradigms, the possibilities are great that on-farm experience will vary from research results. Health and Welfare's review is addressing the controversy over efficacy, and the "value for the dollar" of the product (6).

Animal Health

2. What will be the lifelong health impact on the cow of BGH injections?

The data are sparse on this question, because most of the trials focus on one breed of cow (Holstein), relatively small groups of animals, and relatively short time periods. Concerns, as yet not fully explored, indicate potential problems with elevated stress levels in the animals, increased incidence of infectious diseases, and the potential for increased use of antibiotics (7).

3. What will a lifecycle analysis of cow health reveal about the economic benefits of BGH?

There are some indications that the productive lifespan of the cow may be reduced with BGH application (8). Some evidence has also been incidentally found of reduced fertility (9). The economic implications of these potential problems has not been explored.

Human Safety and Health

4. Are we really sure that BGH is biologically inactive in humans?

The first issue to address is whether or not BGH levels in milk are higher in cows treated with synthetic BGH compared to untreated cows. Published studies suggest that levels of BGH in treated cows are within the physiologic range, however, critics claim that the average levels of BGH in milk from treated cows is higher than that from untreated cows (10). Current technology is unable to differentiate synthetic BGH from natural BGH when testing levels in milk (11).

Reviews undertaken by the Food and Drug Administration and the National Institutes of Health in the United States conclude that BGH is biologically inactive in humans, that at least 90% of BGH is destroyed with pasteurization and that ingested BGH would be degraded in the human gastrointestinal tract in the same way as other proteins (12). Critics argue that synthetic BGH differs by 0.5 to 3.)% from the natural hormone and may therefore induce immunologic or allergic reactions in the gut wall (13). In addition, intact molecules may be absorbed through the gut of newborn infants or those with impaired protein digestion, with, critics suggest, deleterious results (eg. cystic fibrosis) (14).

5. What is the impact of IGF-1 on humans, particularly infants?

Levels of bovine Insulin-like Growth Factor-1 (IGF-1) have been found to be increased in the milk of BGH treated cows (15). bovine IGF-1 is identical in structure to human IGF-1 and so potentially poses a greater risk that BGH. In addition, bovine IGF-1 is not destroyed by pasteurization although it is destroyed by processes used to prepare infant formula.

Animal studies have reported physiological changes following administration of IGF-1, however, these have been discounted as incidental finding (16). The NIH report has concluded that the local effect of IGF-1 on the exophagus, stomach or intestine is unknown (17).

6. Is the nutritional value of milk altered?

Some analysts claim there is no discernible change in milk composition (18). Others (19) identify studies that have found increases in fat content, decreases in casein proteins, and elevated levels of serum proteins, particularly when the animal's nutritional requirements are not adequately met. It is recognized that using BGH requires even greater management skills on the part of the farmer. Critics worry that an inability to meet these requirements will result in decreased nutritional quality.

7. If the product is licensed, are consumers likely to decrease their milk consumption, and substitute less nutritious drinks?

This may well be the most important human health effect resulting from the use of BGH in cows. Milk (including milk products) is one of the most important foods in our diet and supplies about 70% of our total calcium intake (20). Several USA surveys have concluded that consumers would decrease their consumption of dairy products if BGH were being used, however, the results of the survey depended on how the question was framed (21). In addition, consumers in British Columbia refused to buy milk from a dairy that was being supplied with milk from BGH treated cows (22).

8. What is the impact on humans of increased infections or reduced fertility in treated cows?

It has been alleged that unpublished industry studies show that treated cows have an increased incidence of mastitis (inflammation of the udder) as well as other infections (23). Antibiotic treatment of cows may result in antibiotic-resistant disease-causing organisms, for example, a serious outbreak of salmonella in humans was associated with beef from antibiotic treated cows in the United States (24).

Reduced fertility in treated cows may potentially impact on human health if these cows are given fertility drugs to compensate for the effects of BGH.

9. What is the effect of fat soluble chemicals that may be mobilized by BGH treatment?

BGH treatment induces the mobilization of fat stores and reduces total body fat in cows. Many chemicals such as pesticides, PCBs and dioxins, can be stored in the body fat of cows and many be found in increased levels in milk of treated cows (25). Studies addressing the potential significance of this theory have not been done.

Socio-economic impacts

10. What is the impact of the use of BGH on Canadian dairy farmers?

Some studies of the macro-economic impacts of BGH use have been carried out in the USA (26), but none have been carried out in Canada. Given the differences in the structure of the two dairy sectors, it is essential that such work be carried out in Canada.

11. Have the ethical implications of using biotechnology in agriculture been fully explored?

Significant issues of animal welfare and the ethics of using genetically-altered organisms have not been addressed.

12. What is the impact on consumer prices?

As no Canadian comprehensive macro-economic studies have been performed, it is not possible to assess the impact on consumer prices.

The process of evaluating the product

13. Are the companies producing BGH having undue influence over its scientific evaluation?

Concerns are being expressed about the relationship between the drug companies and the research community performing the work. Most of the studies are financed by the companies, much of the data is not available for public scrutiny and academic peer review, and little independent evaluation has taken place (27). This problem of commercial - scientist relations is not unique to this issue and has become an endemic problem in the agricultural scientific community (28).

14. What process is being used to fully evaluate the health, economic and socio-economic impacts of the licensing and use of BGH?

Health and Welfare Canada is responsible for determining whether the product will be licensed. Their evaluation is concerned with the clinical effectiveness of the drug and its safety. They require details of the manufacturing process, the tests to control the potency, purity, stability and safety of the drug, and substantial evidence of this clinical effectiveness and safety. The evaluation does not address the broader agricultural policy issues of who benefits from using the drug, and its impact on the dairy industry, on dairy farmers, and on prices. Other agencies who normally address such questions, such as Agriculture Canada and the Ontario Milk Marketing Board, are not undertaking any comprehensive review of the matter. There is no readily apparent avenue for public input into the decision making process.

The Medical Officer of Health concludes that: "The available peer-reviewed literature on BGH suggests that no detrimental health effect is associated with its use in milk production, however, critics point out that the raw data has not been evaluated by independent reviewers. Opposition to the use of BGH on health grounds remains largely theoretical and it is difficult to assess the validity of these claims based on the current literature."

A recommendation to prohibit the use of BGH cannot be made on health grounds alone, however, economic and social factors (such as the belief that consumers would not purchase milk from treated cows) suggest that cautions should be exercised in recommending the use of BGH.

Several jurisdictions in the USA and Europe are raising similar concerns about the licensing and use of BGH, and are not permitting its sale until such concerns are addressed. Some governments have been exploring the potential for labelling BGH-treated milk as a means of providing consumers with a purchasing choice.

Given these gaps in our understanding of the impact of BGH, the Board of Health should:

1. until its concerns about the drug and the evaluation process have been adequately addressed, oppose the licensing and use of Bovine Growth Hormone (BGH).

2. communicate the concerns raised in this report to: Health and Welfare Canada, Agriculture Canada, the Ontario Ministry of Agriculture and Food, the Ontario Ministry of Health, the Dairy Bureau of Canada, and the Ontario Milk Marketing Board.


1. One company has produced a product with an identical amino acid sequence to naturally-produced BGH.

2. Baumann, D. et al., 1985. Responses of high producing dairy cows to long-term treatment with pituitary somatotropin and recombinant somatotropin. J. Dairy Science 68:1352-1362.

Baumann, D. et al., 1985. Sources of variation and prospects for improvement of productive efficiency in the dairy cow. J. Animal Science 60:583-592.

3. Canadian Animal Health Institute. undated. Biotechnology in the Dairy Industry: Bovine Somatotropin (BST). Canadian Animal Health Institute.

4. Address by Dr. John Burton, University of Guelph, to the Toronto Board of Health, July 10, 1991.

Epstein, S.S. 1990. "Potential public health hazards of biosynthetic milk hormones." International J. Health Services 20:73-84.

5. Brooks, H.G. and Furtan, W.H. 1985. An analysis of public agricultural research in the Canadian prairie provinces. In: K.K. Klein and W.H. Furtan (eds.). Economics of Agricultural Research in Canada. University of Calgary Press, Calgary. Pp. 53-72.

Ruttan, V.W. 1982. Agricultural Research Policy. University of Minnesota Press, Minneapolis.

Busch, L. 1984. Science, technology, agriculture and everyday life. In: H.K. Schwarzweller (ed.). Research in Rural Sociology and Development: focus on agriculture. Vol. I. JAI Press, Greenwich, CT. Pp. 289-314.

6. Dr. Len Ritter, Bureau of Veterinary Drugs, Health and Welfare Canada, phone conversation of 7/8/91.

7. Hansen, M.K. 1990. Biotechnology and Milk: benefit or threat: an analysis of issues related to bGH/bST use in the dairy industry. Consumer Policy Institute / Consumers Union, Mt. Vernon, NY.

8. Address by Dr. John Burton, University of Guelph, to the Toronto Board of Health, July 10, 1991.

9. Epstein. 1990. op.cit.

10. Daughaday, W.H. and Barbano D.M. 1991. "Bovine Somatotropin." JAMA 265(11):1389-90.

Kronfeld, D.S. 1991a "Bovine Somatotropin. JAMA 265(11):1389.

11. Kronfeld. 1991a. op.cit.

12. Juskevich, J.C. and Guyer, C.G. 1990. Bovine Growth Hormone: human food safety evaluation. Science 249:875-884.

NIH. 1991. "Technology Assessment Conference Statement on Bovine Somatotropin." JAMA 265(11):1423-24.

13. Epstein. 1990. op.cit.

Kronfeld, D.S. 1991b. "Safety of Bovine Growth Hormone." Science. 251-256.

14. Epstein. 1990. op.cit.

15. Hansen. 1990. op. cit.

16. Juskevich and Guyer. 1990. op.cit.

Mepham TB. 1991. "Bovine somatotropin and public health." BMJ 302:483-4.

17. NIH. 1991. op.cit.

18. Address to the Board of Health, Dr. John Burton, University of Guelph, July 10, 1991.

Juskevich and Guyer. 1990. op.cit.

19. Hansen. 1990. op.cit.; Epstein. 1990. op.cit.

20. NIH. 1991. op.cit.

21. Marketing Research and Counseling Services. 1990. Consumer Reaction to the Use of BST in Dairy Cows. Prepared for the National Dairy Promotion and Research Board. Arlington, VA.

22. S. Styliadis. Veterinary Consultant, Public Health Branch, Ontario Ministry of Health. Personal Communication 15/8/91.

23. Epstein. 1990. op.cit.

24. Holmberg, S.D. et al. 1984. "Drug-resistant salmonella from animals fed antimicrobials." NEJM 311(10:617-22.

25. Epstein. 1990. op.cit.

26. These studies generally concluded that there would be very significant restructuring of the US dairy industry, including large reductions in the number of dairy farms. See for example:

Kalter, R.J. et al. 1985. "Biotechnology and the dairy industry: production costs and commercial potential of the bovine growth hormone." A.E.A. Research 85-20. Ithaca, NY: Cornell University Department of Agricultural Economics.

Office of Technology Assessment. 1986. Technology Public Policy and the Changing Structure of American Agriculture. OTA-F-285. Washington, DC: US Government Printing Office.

27. Hansen. 1990. op.cit.; Epstein. 1990 op.cit.

Kneen, B. 1990. "Modern farming practices: a consideration of Bovine Growth Hormone." The Ram's Horn 74:1-8.

Roush, W. 1991. "Who decides about biotech?: the clash over Bovine Growth Hormone." Technology Review July:29-36.

28. MacRae, R.J. et al. 1989. "Agricultural science and sustainable agriculture: a review of the existing scientific barriers to sustainable food production and potential solutions." Biological Agriculture and Horticulture 6:173-219.

Jennifer Welsh Jack Layton

Co-chair, Co-chair,

Toronto Food Policy Council Toronto Food Policy Council


Copyright 1991 .Toronto Food Policy Council All rights reserved.

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