recombinant Bovine Growth Hormone
recombinant Bovine Growth Hormone
Several years ago, dairy farmers across the country began administering recombinant bovine growth hormone (rBGH) to their herds in order to increase milk production. Many issues and concerns were raised as a result of this practice, some more valid than others.
Originally, the idea for injecting dairy cows with rBGH came from the finding that cows that normally have higher levels of BGH in their bloodstream also produce more milk. So veterinary scientists used recombinant DNA technology (thus the r in rBGH) to insert the gene for BGH into bacteria, which would then produce the BGH protein. The intended use for this rBGH was to treat low-milk producing members of a herd to bring them up to the level of production of the rest of the herd, not necessarily to treat the entire herd (which is what ended up happening in many cases).
You don't get something for nothing, though, and in this case the tradeoff was not only the cost of administering the drug, but also the health of the cow. Cows treated with rBGH often suffer from inflamed joints, susceptibility to udder infections, and a higher rate of miscarriage. What this means is that large dairies that have veterinarians on their in-house staff have a much easier time of adopting the technology than small dairies that have to pay for individiual veterinary visits every time the drug is administered or there's a problem. In addition, there already existed an excess of milk production, trimming margins and making profitability more difficult for small volume producers. Thus, small dairies are placed at a significant competitive disadvantage.
The organized opposition to rBGH rarely raised these issues, however, preferring instead to try to frighten consumers with threats of feminized boys, skyrocketing cancer rates, and milk tainted with antibiotics. At one store (source: Usenet), protesters reportedly took to handing out flyers featuring someone dressed in a tyvek hazmat suit milking a cow. I believe this whole strategy was inappropriate.
Boys with Breasts -- Hormones can be divided into two categories: protein hormones and nonprotein hormones. Nonprotein hormones (such as those found in birth control pills) do not get digested by the enzymes in our stomach and intestine and can, therefore, be taken orally. Protein hormones (such as insulin) cannot be taken orally because they get digested (and inactivated) in our stomach the same way that hamburger and tofu are. rBGH is also a protein and, as such, gets digested and inactivated in our stomach. Besides, as mentioned above, we have already over the years bred cows to produce more of their own BGH, with no ill effects on those consuming it.What was most frustrating for me in this experience was that, even though I came out strongly against rBGH, I ended up spending most of my time arguing with other individuals who also opposed the use of rBGH, instead of talking to other people who weren't opposed to its use because they didn't have access to any information. The negative effects of the technology on the cows and on small farms were clear; but instead, opponents of rBGH chose to make up or exaggerate the human health risks associated with its use, risks with little or no basis in truth. It still bothers me. Just because it's hard to get Americans worked up about animal welfare and small farm issues does not mean it's okay to invent or exaggerate threats to human health.Cancer -- Treating cows with rBGH, in addition to increasing milk yields, also results in elevated levels of insulin-like growth factor 1 (IGF-1). It has been found that certain types of cancer are associated with higher than normal levels of IGF-1 in the blood and that cells in petri dishes treated with IGF-1 can become cancerous. Opponents of rBGH claimed that this meant drinking milk from rBGH-treated cows would cause cancer. Again, IGF-1 (insulin-like growth factor 1) is a protein that gets digested in our stomach and doesn't make it into our bloodstream. And even if some should make it across our intestine, that amount would be minuscule compared to the amount that our body normally produces.
Antibiotics -- This is the one point that I believe is really worth thinking about, but not for the reasons that the opposition has presented. According to their view, use of rBGH results in more frequent udder infections (true), which results in more frequent use of antibiotics (true), which means more antibiotics in our milk supply (very unlikely). The reason this isn't likely to happen is that cows treated with antibiotics must be taken out of milk production until the drugs have cleared from their system and no longer appear in their milk. There are serious economic penalties for farmers who do not follow the rules. They lose the money the would have received for the good milk in the batch, they have to pay for the disposal of the milk, and they have to pay to have the tanker carrying the milk cleaned out.
But it is true that reducing the frequency with which antibiotics are applied is a good idea. Drug resistance in bacteria is becoming a dangerous problem and we need to reexamine the way that antibiotics (even the triclosan in antibacterial soaps at home) are used.
(October 2003)