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Bovine Growth Hormone in Milk

Sep 10, 2011 | By Raven Demers
Bovine Growth Hormone in Milk
Photo Credit BananaStock/BananaStock/Getty Images

Drinking three glasses of milk a day has been a hallmark of health in the U.S. for decades; its nutrient content is rich in vitamin D, calcium and riboflavin. A glass of milk contains approximately 7.9 g of protein. However, there are groups of people who do not believe milk is healthy to drink. More believers joined their ranks in 1993 when the United States approved the use of recombinant bovine growth hormone, rBGH, to increase milk production. As of 2011, the use of rBGh by U.S. dairy farmers continues to be controversial in the global market.

Bovine Growth Hormone

Somatotropin is naturally secreted by the pituitary glands of mammals to promote healthy body growth. This protein hormone was isolated in 1945 and used in experiments on the growth of laboratory animals. In its synthetic form, it can be called either rBGH or recombinant bovine somatotropin, rBST, and is used primarily to increase milk production of dairy cows in industrialized farming operations.

Effects on Cows

Cows treated with rBGH undergo chemical changes in order to produce larger quantities of milk. Increased milk production places greater demands on a cow’s body leading to a reduction of body mass, mastitis—an infection of the mammary glands—and delayed fertility. Antibiotics are given to cows who suffer from infections related to rBGH, and those antibiotics can leach into the milk produced for human consumption. Treated cows have a higher protein requirement, and some are fed ground up animal remains and chicken waste in order to meet these nutritional need.

At the Market

The U.S. FDA allows voluntary labeling of milk from cows not treated with rBGH or rBST, but any labeling is not a sign of FDA approval or support. The practice of labeling milk as being free of synthetic hormones is a point of contention between different interests groups, including farmers, the companies that produce rBGH and consumers who are either for or against the use of the use of synthetic hormones. Since natural bovine growth hormone is already found in milk, labeling is not necessary for untreated cattle. However, as of 2011, U.S. milk continues to not be accepted for purchase or use in the European Union, Japan, and Australia among many countries, due to concern about the safety of milk from treated cows. Consumers who prefer untreated cow’s milk look for dairy with the FDA approved labels.

Effects on Humans

Sufficient scientific evidence is inconclusive as to the safety or harm posed by consuming dairy products from rBST-treated cows. There are some health concerns still being addressed by those involved in food safety from farmers to the FDA. Among these concerns are the levels of pus present in milk from industrial dairy farms and the levels of antibiotics passed through the milk. Recombinant bovine growth hormone also increases the level of another hormone, IGF-1, which is directly responsible for the increased milk production, but can trigger cancer growth in non-infant humans. Studies current as of 2011 show that little, if any, IGF-1 is passed from the cow through the milk, but further research is necessary to assuage fears of safety hazards.

References

Article reviewed by JanetM Last updated on: Sep 10, 2011

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