The US and Canada closed the deal on an updated NAFTA trade agreement last week. One of the key concessions by Canada is opening their dairy sector to more imports of U.S. milk and dairy products, including some from cows given the genetically-engineered hormone rBST.

Canadian dairy farmers and some consumers are less than thrilled.

As CNBC news reports, the use of rBST on American dairy farms, and the prospect of more milk flowing north, is focusing new attention on the pros and cons of recombinant bovine somatotropin, or  rBST.  This synthetic growth hormone is used in around 20% of dairies in America to boost milk production, but has been banned in Canada since the 1990s due to concerns about cow health.

Q+A excerpts follow from the CNBC piece.  Expect to hear more about this in the future as a re-opened Canadian market might create additional pressure on American dairy farmers to either label milk relative to rBST use, or drop use of the hormone.

Verbatim text quoted from the Reuters story.  Pictures and captions added by Hygeia.

What is rBST?

Recombinant bovine somatotropin (rBST) is the synthetic version of the growth hormone bovine somatotropin (BST), which cows naturally produce. Back in the 1930s, researchers realized they could increase milk production by injecting cows with BST, which was helpful in certain countries during food shortages, such as in the Second World War…

In the late 1970s and early 1980s, scientists at biotechnology giants Genentech and Monsanto developed a genetically engineered version, rBST, commercially known as Posilac.

The U.S. Food and Drug Administration approved rBST for use in 1993.

Health Canada reviewed it in the late 1990s but did not approve it.

Why do American farmers use it?

rBST is used to increase a cow’s milk production. A 2003 study published in the Canadian Journal of Veterinary Research found it increased the amount of milk by 11 to 16 per cent. But only a minority of U.S. farms use it. A 2007 United States Department of Agriculture (USDA) study found that only about 17 percent of all American cows receive the artificial hormone.

Why is it banned in Canada?

Health Canada determined rBST posed no health risk to humans who consumed milk from cows who had been given rBST. But it had concerns about the potential health effects on the cows.

A 1999 report commissioned by Health Canada found there was an increased risk in the cows injected with rBST of mastitis, or breast inflammation, of up to 25 per cent; of infertility by 18 per cent; and of lameness by up to 50 per cent.

Can U.S. milk from cows given rBST be sold in Canada?

Yes. Dairy products made with U.S. milk ingredients are already sold in Canada. The main challenge will be knowing, because there are no labeling requirements for dairy products made with American milk to let consumers know when they could be exposed to hormones.

Source:

CNBC, “Hormones, cows and the new trade deal: What you need to know,” October 3, 2018.