Roughly four years ago, dairy farmer Louie Kazemeir stopped using a synthetic hormone that boosts milk production.

If he wanted to continue using recombinant bovine somatotropin, or rBST, Kazemeir would have to pay “astronomical trucking charges” to ship the milk to a segregated location, he said.

“I’m not willing to pay the extra fee,” said Kazemeir, who farms near Rickreall, Ore.

The popularity of rBST has fallen sharply among dairy farmers across the U.S., according to an economic study.

More than two-thirds of dairy farmers who have ever treated their cows with rBST have stopped using it, the study found.

“It was heralded as a savior and panacea for the dairy industry, but it didn’t really turn out that way,” said Henry An, the study’s author and an economics professor at the University of Alberta.

Despite being approved by the Food and Drug Administration, critics of rBST claimed its use was harmful to cows treated with the hormone and potentially dangerous to human milk consumers.

Many farmers have likely stopped using rBST due to the backlash against the product from some consumers and because it often doesn’t measurably improve profits, said An, who considers himself an “agnostic” regarding the product’s alleged dangers and virtues.

The steepest drop in rBST usage has been among larger dairies like Kazemeir’s, which raise more than 1,000 cattle. In 2005, about 44 percent of such operations used the hormone, compared to 16 percent in 2010, according to the study, which relied on USDA survey data.

Across all U.S. dairies, the prevalence of rBST usage has declined from about 17 percent to less than 10 percent in that time, the study said.

That’s far below projections prior to the hormone’s approval by the U.S. Food and Drug Administration in 1994, when some economists estimated that between 63 percent and 98 percent of dairymen would adopt the technology, the study said.

While the public controversy over rBST likely discouraged adoption, economic studies have consistently been unable to correlate its usage with higher profits, said An.

The hormone was initially intended to improve the efficiency of dairy production by inducing cows to generate more milk per unit of feed, he said.

However, hitting that “sweet spot” of milk production requires careful monitoring of cow feed consumption, An said. “It’s just not feasible for most producers.”

For many dairies, rBST simply boosted milk output but didn’t put more money into the farmers’ pocket because cows were consuming more feed, he said.

“There seems to be this fixation — how much milk you’re putting out, when you should be concentrating on how much money you’re making,” An said.

Since some dairies are continuing to use rBST, it suggests that they’re able to perfect its usage enough to increase profits, he said.

On average, though, the product hasn’t been associated with better margins, An said.

The lack of a strong economic incentive to treat cows with rBST was likely a deciding factor in many dairy farmers’ discontinuation of the technology, he said.

For retailers, milk is often a “loss leader” that’s intended to get consumers in the door, An said.

When a vocal group of opponents protested rBST usage, some retailers figured they weren’t making money on milk anyway and so it wasn’t hard for them to reject milk from rBST-treated cows, he said.

“It’s a good candidate to make a token gesture, if you will,” An said.

The retailer response prompted some major dairy cooperatives to pay farmers less for milk from rBST-treated cows, due to the segregation costs involved, he said.

“That was one of the last straws for people,” An said. “If you’re not making much money to begin with, then you get docked, what’s the point?”

Capital Press was unable to reach Elanco, which manufactures rBST and sells it under the Posilac brand name, for comment.

Cow health problems also likely contributed to the dropping popularity of rBST, said Rick North, a longtime opponent of the hormone and the retired director of the Campaign for Safe Food, a subsidiary of the Physicians for Social Responsibility non-profit.

The hormone causes increase mastitis, or inflammation of the udders, which forces dairies to remove cows from production and spend more money on antibiotics, he said. “It just burns these cows out.”