In 1993 the US dairy industry changed dramatically. That year the FDA approved the use of a genetically-engineered form of bST, sparking a controversy that has persisted over the last thirteen years, leading to law suits and disputes over public health and safety. Many organically-minded consumers switched over to "hormone-free milk," only to later learn that there was no such thing. What is rbST anyway, and how does it affect cows? The intent of this article is to sort through the issues concerning rbST, so that you can make an informed decision about the milk you buy.



Somatotropin (bST) is the hormone which stimulates milk production and is naturally produced in a cow's pituitary gland. In the 1950s scientists first developed a recombinant form of this hormone, hoping to use it to treat children suffering with dwarfism. The injections had no effect whatsoever on the children, and the experiment was deemed a failure. Scientists concluded that some hormones were species-specific, meaning they only affect members of their own species. In the 1980s scientists had a new use for the synthetic hormone-inject cows with it to stimulate greater milk production. Studies began to see if such a theory would work.

The use of rbST (which is also called rbGH, Posil, or Bovine Growth Hormone) is often misunderstood. Misinformed individuals think that farmers who use the synthetic hormone use it 100% of the time with their entire herd. This is simply not true. rbST is used in synch with a cow's natural lactation cycle. Soon after a cow gives birth she reaches her peak milk production-a state called freshening. Sometime thereafter, her production steadily declines until she goes dry. The average cow produces milk 306 days out of the year. rbST is used toward the end of the freshening stage, to prolong higher milk yields later into the cycle. If a cow is already at peak production, rbST will not yield more milk. Neither does the hormone affect all cows equally. While the hormone boosts production in the average cow by 10-15% per year, some cows may not be affected at all. Dairy farmers therefore use the hormone on about a third of the herd at a time.

The Controversy

In 1993, amid a storm of controversy, the FDA released its conclusions regarding the use of rbST in dairy cows. None of the studies performed detected any significant difference in the milk of cows which had been treated with the synthetic hormone versus those who had not. Even if the hormone was passed in higher concentrations in the milk, which it wasn't, the FDA asserted that rbST would have no affect on humans. Therefore, the FDA did not require farmers using rbST to label their products.

When some organic farmers voluntarily labeled their milk as "hormone-free" or "bST-free," the FDA sued, saying that all milk contained natural hormones, and that the voluntary labels misled the public into thinking organic milk was healthier. Appropriate wording was finally agreed upon, and organic dairy farmers now inform their consumers that products have been made using milk from cows not treated with rbST. As a result of the law suit, organic farmers must also state that the FDA has found no difference in the milk produced by treated and untreated cows.

Their findings would have packed more power, had not three voices joined the resistance. Richard Burroughs, who played a lead role in the FDA review process, was shocked at how few tests the agency was running. When his questions threatened to slow down the approval process in the late 1980s he was fired. Alexander Apostolou was also pressured to leave the agency when he publicly stated that "sound scientific procedures for evaluating human food safety of veterinary drugs have been disregarded." It should be mentioned that neither Burroughs nor Apostolou objected outright to the drug, but advocated more thorough testing. Their concerns were not appreciated. They were joined by Joseph Settepani, a chemist in charge of quality control for veterinary drug approvals. After testifying at a public hearing that a systematic breakdown in testing had occurred, Settepani was stripped of his duties as a supervisor and sent to work in a small experimental farm. During this time numerous letters were sent by FDA workers expressing their concerns about the inadequate testing, choosing to remain anonymous because they were afraid of retribution.

Other countries, experiencing the same backlash, made different choices. To date, Canada, Europe, Japan, Australia, and New Zealand have barred the use of rbST in their dairy cows. While their decision may be pitted more in politics than in human safety, (increasing the milk supply would drive down the price, forcing taxpayers to spend more money on farmer subsidies), at least two Canadian studies have yielded questionable results. In the first, it was suggested there may be a very rare sensitivity to food products from rbST-treated cattle. A subsequent study in 1998 found increased risks in animal safety. Treated cattle were 25% more likely to suffer from mastitis, 18% more likely to be infertile, and 50% more likely to go lame.

Whether or not milk from rbST-treated cows is really any different, the controversy has resulted in a steady market for organic dairy farmers. Since 1993, the demand for organic milk has increased 500%, and at present, the demand is greater than the supply. While the FDA is unlikely to back down, it appears dairy farmers are responding to their market. Last week on the shelves of the dairy case I noticed traditional farmers are now offering their own milk products-produced by cows untreated with rbST.