The rBST controversy

The rBST controversy

BST (bovine somatotropin) is a hormone that performs a number of duties, one of these being telling the cow’s body it needs to produce milk. This hormone allows feed to be directed towards milk production instead of weight gain, without compromising the cow’s health.

The more BST hormone, generally, the more milk the cow will produce. When farmers choose which bull semen to use in their artificial insemination program, they are willing to pay more for bulls who give birth to cows that produce large quantities of milk. As they selectively breed for more productive cows, they are selectively breeding for cows that naturally produce more BST. You might say that much of the selective breeding occurring in the last half century has been done with the indirect purpose of increasing BST levels in the milking herd.(G1)

Instead of increasing milk production by selectively breeding, why don’t we just inject cows with the BST hormone? Before 1994 this wasn’t commercially possible because creating a synthetic version of the hormone was too expensive. It could only be acquired from the pituitary glands of dead cows. This changed when a biotechnology firm learned to genetically modify a bacteria that would produce the hormone, and the synthetic hormone (referred to as recombinant BST, or rBST) was approved by regulators in the U.S., Mexico, Europe, and elsewhere.(N3)

The rBST has to be given by an injection. Because the hormone is a protein it would be broken down in the digestive system of the cow if added to their feed.

Farmers who use it find that milk production increases by 5 to 15%,(D1,E2,G1) which would be like identifying a particular bull whose progeny would yield 5 to 15% more milk than the offspring of other bulls. It lowers the price of milk, and assuming the production of the rBST hormone doesn’t create a lot of carbon emissions, lowers the carbon footprint of milk.

Less than 25% of U.S. dairy cows receive rBST.(E2) This would be like a majority of producers choosing not to breed their cows to superior bulls, but there is a good reason for this. Ever since its introduction rBST has been controversial. On the one hand, it is approved by most scientific and health organizations, as well as the U.S. Food and Drug Administration. On the other hand, a vocal group of activists are skeptical, and believe that biotechnology corporations are able to use their political influence to “write their own regulations”, in a sense. (See the lecture The left and right side of the table for more information on the politics of genetically modified organisms).

If you go into almost any store in Oklahoma to buy milk you will see two things on the label. First, it will tell you that farmers have “pledged” not to administer rBST to their cattle, as if doing so would be dishonorable. Then the label tells you that there is no difference between milk from cows that did and did not receive rBST. What’s going on?


Is the customer always right?

The farmers’ pledge is in response to consumer concerns. Give consumers a choice between milk that does and does not have this pledge, and consumers will usually take the one with the pledge—they will even pay a premium to do so. At the same time, the pledge alone is like false advertising, since it suggests that milk without rBST is safer, so the seller includes the second part about the FDA to prevent being sued for false advertisements.

It seems as if scientists and consumers believe entirely different things. Indeed, that is exactly what is going on.

What does an economist think about the label saying the farmers didn’t use rBST?

On the one hand, if many consumers are truly concerned about the use of rBST, then perhaps they have the right to know whether it was used to produce their milk. Consumers have that right regardless of whether scientists and regulators agree with them.

On the other hand, saying the milk was produced without the use of rBST suggests there is something dangerous about milk from farms that did use rBST. For instance, what if a company put on its label that it was produced by farmers who pledged not to feed their cows Alfalfa hay, when we know there is absolutely nothing wrong with feeding alfalfa hay? The average person would naturally infer that there is something dangerous about Alfalfa hay. It deceives consumers.

I was thinking about this issue one day when I watched a scene from the comedy show Arrested Development which demonstrated well the deceptive nature of labels. The character Gob Bluth suggests the slogan of his family’s construction company should be, “The Bluth/Morento Company: A Columbian cartel that won’t kidnap and kill you!”, which the character then explains, “Underline ‘won’t’ because that makes the competition look like maybe they ... [will kidnap and kill you].” You can watch this scene at this link.

In ensuring a safe food supply we tend to rely on two things (among many others): scientific evidence and intuition. This intuition is formed from tradition and beliefs about the way the natural world works. Science lets us go beyond intuition, to accomplish remarkable things that are impossible with traditional agriculture, like complete animal feeds (feeds providing all the animal’s nutrient requirements) and artificial insemination. Intuition cautions us against straying too far from nature, and reminds us that when you use new technologies it is impossible to predict all the consequences.

I suggest that consumers want the right to know about activities or ingredients that concern people, but only those things for which there is valid evidence for concern. Most people have considerable respect for the scientific organizations and governmental agencies like the FDA that have deemed rBST safe. At the same time, they know scientists and the FDA have been wrong in the past (scientists are humans, after all).

An example is the former practice of feeding cattle the rendered carcasses of sheep, only to find that it probably caused Mad Cow disease. This is a case where scientists were proven wrong and those advocating natural feeds were right. The intuition of what is “natural” was more accurate than the scientific consensus. This is one reason why people today protest the feeding of processed chicken manure to cattle—not a widespread practice, but an accepted one.

The awkward label on milk tries to accomplish both. It says there’s no reason to be concerned about rBST, but if for some reason you are, this milk was produced by farmers who didn’t use it.

Let me conclude by summarizing the various views on rBST.

Milk from cows administered rBST

  • The FDA (and virtually all prestigious scientific organizations) have concluded that milk from cows that are and are not administered the rBST hormone are virtually indistinguishable. The chemical composition of the rBST and the naturally produced BST is identical. The quantities of BST and rBST in a gallon of milk are also identical. Even if the quantity and composition of BST and rBST were not identical they are inactive in the human body, and so would not affect health. Any other differences in the two milks have no impact on human health.
  • It is likely true that cows receiving rBST are more likely to develop mastitis, but that is also true for cows that produce more milk naturally. If a cow has mastitis its milk does not enter the supply for human consumption. Also, cattle are often given antibiotics to treat mastitis, and milk from cows receiving antibiotics cannot be used for human consumption. The FDA has a zero tolerance for antibiotic residues on milk, and of the 3.7 million samples that were tested in 2012-2013, only 731 tested positive for residue (0.0198%).(G2) If rBST makes cattle more likely to develop mastitis then it would impair animal welfare, but not human health. Groups opposed to rBST have claimed that the corporation developing rBST hid the association between rBST and mastitis. That may or may not be true, but it is an association scientists probably expected anyway, and so long as regulations are enforced, that relationship may be bad for the cows but not for human health.
  • There has been some controversy around something called IGF-1, which stands for “insulin-like growth factor 1”, which are in higher amounts of milk from cows treated with rBST. People with high levels of IGF-1 in their blood may have a greater chance of developing cancer(Y1), but the literature is far from certain. Moreover, while adults who drink milk are more likely to have higher IGF-1 levels, the same is true for people who drink soymilk(A2). All of this the FDA knows, and it has reviewed scientific studies but found there was no basis for concern(J1). So this has become one of those things that, if you are naturally fearful of rBST, it can add to your anxieties, but if you trust the regulatory system then there is nothing to fear.
  • When Ohio tried to enact a ban on labeling milk “produced without rBST” the court ruled that milk from cows treated with rBST is compositionally different, due to the higher levels of IGF-1. So this is an issue still being fought in the public and the legal hemisphere.(M3)

Consumers are the boss

Despite all of this, it is increasingly rare to find milk from cattle that receive rBST treatments, and this is because critics have won the public-relations battle. Less than 25% of cattle in the U.S. today receive rBST, and I have been told that no milk sold in Oklahoma comes from cows receiving rBST. This probably means that the milk from cows receiving rBST is sold not as fluid milk but for use in making products like yogurt, cheese, and butter.

Consumers have been convinced that rBST compromises the milk in some way, and this increases the demand for milk from cows not receiving rBST and decreases the demand for milk from cows that do receive rBST. The whole rBST controversy has stigmatized milk from rBST-treated herds, something that can be detected in laboratory experiments with consumers.(K1)


(1) Personal photograph.