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Learning to Love rbST

Despite the proven safety of rbST and its effectiveness in reducing the carbon and nitrogen footprint of dairy cows, the industry eliminated rbST use because of consumer pressure... rbST is a synthetic hormone based on the somatotropin hormone that cattle naturally produce. Both the natural and synthetic versions play a role in how nutrients in the animal's diet are directed toward body functions (for example, they reduce how much dietary nutrients are needed for maintenance needs like respiration making more available for milk production). As such, rbST makes milk production more efficient, reducing the amount of energy, protein, and feed needed to produce a unit of milk by 11.8%, 7.5%, and…

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Articles of Interest

A meta-analysis review of the effects of recombinant bovine somatotropin

In conclusion, the study found that there was approximately a 25% increase in the risk of clinical mastitis in rBST-treated cows. It appeared as though there may also have been a slight increase in the prevalence of subclinical intramammary infections, but the data relating to subclinical mastitis was limited.

Busted: rbST Milk Myth Machine is Revealed

The sad think is that no milk is free of BST; all milk contains BST and numerous other hormones, all produced naturally by our cows. In fact, all milk contains some hormones, and human milk can contain significantly greater amounts of progesterone and/or estrogen than good old bovine milk. But, is there really a consumer worry?

Is Milk from rbGH-Injected Cows Safe? Why Isn\'t It Labeled?

Bovine growth hormone (bGH), also called bovine somatotropin (bST), is unrelated to steroid hormones. bGH, produced in the pituitary glands of dairy cows, is a naturally occurring protein hormone in milk, which stimulates the liver to produce insulin-like growth factor-I (IGF-I). The structure of human somatotropin differs from bGH, and the latter is not biologically active in humans. Upon pasteurization, 90% of bGH is destroyed; digestive enzymes degrade the remainder. Other growth factors in milk (e.g., the cytokines IL-1 and IL-2), though sometimes slightly elevated in milk from bGH injected cows, are inactive in other mammals.

rBGH Decoded: What you Need to Know about Hormones in Dairy

rBGH isn’t the only mixed-capitalization initialism in the dairy case. You may also see “rBST-free” claims on products. rBST stands for recombinant bovine somatotropin. Somatotropin is the specific name of the growth hormone secreted by the pituitary gland—it’s the same thing as rBGH, just labeled with a few different letters.

rbST and Milk: Answering Consumers’ Questions

You’ve probably seen labels on milk jugs saying something like, “From cows not treated with rbST. The FDA has stated that there is no significant difference between milk from cows treated with rbST and cows not treated with rbST”. Have you ever wondered what those labels mean? Or have you ever struggled to explain them clearly to a consumer? Let’s unpack them a little bit.

rbST Safety Around the World

No country has banned the importation of milk or milk products from the U.S. or from any of the countries where rbST has been approved and registered. Milk from cows supplemented with rbST can be exported anywhere in the world (U.S. Dairy Export Council).

What’s In Your Milk? It’s Not What You Might Have Heard

All milk contains naturally-occurring hormones, one of which is bovine somatotropin (BST), aka bovine growth hormone (BGH), which helps cows produce milk. rBST is the synthetic form of BST and was approved in the 1990’s to be given to dairy cows to help boost milk production. BST nor rBST make the cow or calf grow faster. While hormones in the milk help the calf develop, the calf’s own growth hormone has more of an effect. This hormone is species-specific, meaning it does not do anything in humans. Studies done on BST and rBST indicate that it will not survive human digestion and is actually broken down because it’s an amino acid, nor does it have an effect on human growth hormone receptors. In fact, 90% of BST is killed during pasteurization; the rest is digested.

Why is the artificial growth hormone rbST banned in Canada?

Recombinant Bovine Somatotropin (rbST), is not allowed in Canada. Health Canada made the decision to not approve it in 1999 due to concerns about its impact on the health of animals. Canadian dairy farmers care deeply about the health of our animals. So milk produced in Canada is rBST-free, as rbST cannot be sold in Canada and cannot be imported.

Resources

ProCon.org

rbST boosts milk production in the average cow by about 10 percent to 15 percent. Higher and lower increases are not unknown; rbST impacts different animals differently.”