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30 Days on a Prairie Farm: Milk

30 Days on a Prairie Farm: Milk
Day 9: What's BST? What's rBST? What's the difference? Who cares?

Last fall, I stood on the Lindale Holsteins farm at Hampshire and listened as their veterinarian explained to a group of Chicago moms what's up with hormones in milk. And yes, this was the same tour where Mike Martz explained hormones in steak. It was a big and wonderfully informative day.

The farm is owned by Dale and Linda Drendel, and they invited their veterinarian, Brian Gerloff, to speak with the moms about some of the more technical aspects of their business. For his part, Gerloff did a fantastic job explaining the science and doing so without jargon, and separating science from marketing.

Veterinarian Brian Gerloff explains hormones in milk to a group of Chicago moms: "The short answer is no, it's not causing young girls to develop quicker."

Gerloff explained that artificial growth hormone was approved 20 years ago by FDA as a production enhancement tool. "Essentially, it's the same hormone as cows produce normally to stimulate milk production. They have to produce a calf every year to produce milk and with the artificial growth hormone, they don't have to reproduce as quickly," he explained. Bovine somatotropin, or BST, is the naturally produced hormone in cows; the artificial hormone is called recombinant bovine somatotropin, or rBST.

But the past six or seven years have seen dramatic consumer backlash against having artificial hormones injected into the cow. "As a result of that, a number of the grocers and processors said, 'we think we can sell our milk more easily if we can label it without growth hormones,' even if there are no problems using it and it's perfectly safe," Gerloff said.

"And I personally have no problem drinking it," he added.

It was at about this point in the conversation when I raised my hand and asked him about girls developing sooner - and although everyone want to pin that to hormones in food, is there any evidence that's the cause?

"The short answer is, no. It's not causing young girls to develop quicker. As I look at the population, you certainly want to make the argument that a lot of it is from eating too much - too much fat, too many calories," Gerloff answered.

Gerloff adds that all milk - even human breast milk - contains hormones. Indeed, milk processors can't label milk as "hormone-free" because it's not possible for milk to be hormone-free. They can label it "rBST-free" or "free of artificial growth hormone," but they can't claim it to be hormone free.

And further, rBST and BST are so similar, there is no scientific test available to screen the milk for artificial hormone. So if you buy rBST-free milk, you are buying it based on a pledge from a dairy farmer.

Further again, a study published in the Journal of the American Dietetic Association looked at the quality, nutritional value and hormone composition of milk purchased at retail stores that were labeled according to farm-management practice—organic, processor-certified as not from cows supplemented with rbST, or conventional.  The study found that the type of label was not related to any meaningful differences in nutritional value, quality, or hormone composition. 

In the end, I like Gerloff's conclusion the best.

"Is the milk safe? That's a simple question. Yes, it's safe. Should consumers have a choice? Legitimate question," he said.

Which is to say, when a dairy farmer pledges not to use rBST, it's not a scientific decision. It's a marketing decision, based on a consuming population that wants a choice.  

And marketing. Field mom Julie Barreda offered up a wise observation on hormones in milk at the end of our tour. "It seems like more hype than truth, and it's interesting what marketing puts into our head. That doesn't mean I'm less concerned, I just feel better educated."

Amen, sister.


The archives: 30 Days on a Prairie Farm

Kickoff: 30 Days on a Prairie Farm

Day 1: Working Kids

Day 2: Biotechnology

Day 3: Harvest Eats

Day 4: Church

Day 5: Biotechnology, Again

Day 6: Long Haul

Day 7: Hormones

Day 8: Weather

Day 9: Milk

Day 10: County Fairs


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