Steve Hoffman, director of the Organic Center, updates us on industry efforts to promote the use of bovine growth hormones, below. As you may be aware, bovine growth hormones rBST or rBGH have been implicated in certain health issues, including higher levels of IGF-1, a factor in the growth of breast, prostate, and colon cancers. What's disturbing is the way in which Monsanto, via carefully crafted studies authored by their own scientists, attempts to capitalize on climate change fears to force dairy farmers and shoppers to accept these added hormones in dairy. I have seen the same sort of "science" in the push for wider acceptance of GMOs recently. In addition to the following, read Scientific American's “Can Bovine Growth Hormone Help Slow Global Warming?” by David Biello for more commentary.
Two studies appeared in the last month in important journals comparing the impacts and benefits of alternative dairy cow management systems. Both will no doubt trigger spirited debate on the impacts of dairy cow management systems on the environment and milk quality, as well as the current state of American science.
A study in the Proceedings of the National Academy of Sciences focuses predominantly on climate change and environmental impacts, and is entitled "The environmental impact of recombinant bovine somatotropin (rbST/rbGH) in dairy production."
The piece in the July 2008 Journal of the American Dietetic Association (JADA) addresses the impact of farm management on milk nutritional quality and safety, and is called "Survey of Retail Milk Composition as Affected by Label Claims Regarding Farm-Management Practices." It is co-authored by 10 scientists, six of which work for Monsanto. All the authors have been closely associated with, and strong supporters of rbST/rbGH technology.
Both articles are co-authored by Roger Cady, a Monsanto scientist. One of other co-authors of the PNAS article is Dr. Dale Bauman of Cornell, who is one of the scientists that discovered the ability of rbST/rbGH to increase milk production. He is among the patent holders in the technology, and has long been a paid consultant to Monsanto.
The PNAS study concludes that administering rbST/rbGH to cows reduces:
Feed needs per unit of milk output,
Area of cropland needed per unit of milk production,
Loss of nitrogen and phosphorous per unit of milk, and
Global warming potential.
According to this article, cows treated with rbST/rbGH have a lessened impact on the environment than conventional cows not treated with rbST/rbGH, and organic systems have by far the greatest impact on the environment, per unit of production, largely because of the assumed 25% reduction in daily milk yield.
The JADA Article
The Monsanto team tested conventional, rbST/rbGH-free, and organic milk samples bought at retail outlets. Their "quality" parameters were antibiotics and bacterial counts. "Nutritional value" was measured by fat, protein, and solids-not-fat. No explanation was given why the two nutritional quality parameters known to favor organic milk – Conjugated linoleic acid (CLA) and omega-three levels – were excluded from the study.
The "Hormonal composition" of milk included testing for somatotropin, insulin-like growth factor-1 (IGF-1), estradiaol, and progesterone.
The team reports only minor differences across the three types of milk in most variables studied. They state that bacterial counts were lowest in conventional milk, but the differences were not "biologically meaningful." No antibiotics were detected, which is not surprising, given that the antibiotic tests were done with relatively insensitive quick test-strip kits.
The most interesting finding, not dwelled on by the authors, was that organic milk had by far the lowest IGF-1 level – 2.73 ng/ml compared to 3.12 ng/ml in conventional milk (a reduction of 12.5%). The authors report that because ultrapastuerization can degrade IGF-1, they did not include any organic milk that was, according to the label, ultrapasteurized. The paper does not mention that this seemingly reasonable decision by the team excluded from the samples of organic milk the products of several of the most technologically advanced organic dairy processors.
They note that some organic milk may still have been ultrapasteurized (although not labeled as such), thereby reducing the average IGF-1 level in organic milk.
The authors conclude that –
"It is important for food and nutrition professionals to know that conventional, rbST/rbGH-free, and organic milk are compositionally similar so they can serve as a key resource to consumers who are making milk purchase (and consumption) decisions in a marketplace where there are misleading milk label claims."
Only July 2, 2008, Scientific American ran a story entitled "Can Bovine Growth Hormone Help Slow Global Warming?" by David Biello.
The Scientific American article describes some of the analytical and technical problems with the study, while also pointing out the possible bias that could have been interjected into the project by virtue of its co-authors. The current controversy over labeling milk as rbST/rbGH-free is also mentioned.
Dr. Michael Hansen, a biologist working for Consumers Union, explains in the piece that the findings all hinge on one assumption – that rbST/rbGH increases feed efficiency per pound of milk produced. According to Hansen," If this basic assumption is wrong, then everything that flows from it is of questionable status."
Biello goes on to report that Monsanto tried 15 years ago to get the FDA to accept an "increases feed efficiency" claim on the label of Posilac (rbST/rbGH injections), but the agency denied the claim because insufficient data had been reported to substantiate the increase.
The article reports that the U.S. dairy industry has reduced GHG emissions per unit of production by 70% since the 1940s, through better feeding and genetics. Scientists in Australia also report that they can cut methane emissions another 50% by increasing the percentage of digestible grasses in cow rations.
Editor's Note: As we have said before, sorting out the differences in the environmental impacts of a well-managed, high-production conventional dairy farm that uses rbST/rbGH, compared to a well-managed, grass-based organic dairy farm is a complicated and important challenge. This PNAS article, and the study it covers, provides absolutely nothing of value in meeting this need.
Students of science journalism would have to look long and hard to find a more cleverly and consciously biased article. The co-authors overstate the benefits of rbST/rbGH treated cows, claim benefits that do not exist, and fail to cover aspects of environmental impacts known to favor organic and/or grass-based production systems.