A U.S. Department of Agriculture survey in 2007 determined that about 15% of dairy farms use rBST and 17% of cows are injected. That’s down from 22% of cows in 2002. Large farms are far more likely to use rBST than small farms.

As part of its Campaign for Safe Food, the Oregon chapter of Physicians for Social Responsibility has compiled a growing list of companies that have gone partially or completely rBGH-free. Project Director Richard North estimates that 40-50% of milk on the market today is rBGH-free and 6-7% is organic. (link below)

“Organic sales have been growing fast on a percentage basis, but it’s still a small drop in the bucket overall,” says Chris Galen. “This is a way for marketers to capture sort of an organic lite product without having to pay the higher price for true certified organic dairy products.”


To complicate this controversy, the public health research on rBGH is far from black and white.

The FDA continues to maintain that there is no difference in the nutrition or safety of milk from rBST-treated vs. untreated cows.

Other studies – mostly conducted in other countries — have failed to find conclusive evidence of dangers to human health. Still, a cadre of environmental, public health and consumer advocates are advising us to play it safe. Suspected health risks have stopped other industrialized countries from approving rBGH, including Canada, Japan, Australia and European Union nations.

In addition to the Oregon PSR, some of the key U.S. organizations raising a red flag include the Center for Food Safety, Food & Water Watch and the Consumers Union.

They have three chief concerns: harm to the cows being treated, antibiotic resistance and an increased risk of certain cancers.

It’s not disputed that rBGH causes medical conditions in cows, including increased rates of an udder infection called mastitis, lameness and infertility. Some scientists and animal welfare advocates say the injections also shorten a cow’s life span.

Cows with mastitis are treated with antibiotics, leading to concern about antibiotic resistance in humans. The Consumer Union’s senior scientist Michael Hansen called this a legitimate health concern in an op-ed he recently co-authored: “Bacteria resistant to these antibiotics may pass into humans through milk, air, water or soil…increasing antibiotic resistance.”

Opponents of rBGH say it leads to higher levels of another hormone called insulin-like growth factor 1 — or IGF-1 — in cow’s milk. Jenny Pompilio, a doctor with the Oregon Physicians for Social Responsibility says, “elevated levels of IGF-1 can promote cancers in humans, specifically cancers such as breast, prostate and colorectal cancer.” However, rBGH defenders say IGF-1 does not survive digestion in the human body.

The Oregon PSR has produced an online video and brochure called “Know Your Milk.” Richard North says that despite the lack of a definitive long-term study, there is clear cause for concern. “There’s not 100% proof, but a lot of evidence is pointing in that direction,” North explains. “So our stance is better safe than sorry.”


If you want to avoid rBGH, look for phrases like these on the milk you buy: “produced without artificial hormones,” “rBGH-free,” “rBST-free” or “from cows not treated with rBST.” The product labels appear to be an effective advertisement.

Britt Riedl-Young of Reno, Nevada says she learned about the issue from a milk carton. “I just went to buy milk and when I got it home I noticed that there was a small circle on the label that told me it was hormone free,” Riedl recalls. “I was super happy about it and continued looking for that type of milk.”

This trend has driven Monsanto and some farmers to lobby against the labels. A group of farmers recently launched their own advocacy group called AFACT — American Farmers for the Advancement and Conservation of Technology — to defend their use of Posilac and other biotechnology products.

About half a dozen states have tried to ban or restrict the so-called “absence labels,” partly because there is no test to differentiate between the natural and synthetic BST in milk.