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Scientist sees opportunities for Posilac

Educating consumers about hormone's benefits will spur widespread adoption


Capital Press

A scientist who works extensively with dairy cows believes Posilac still has a future in the industry, though the drug has largely fallen out of favor with some producers.

As the world population grows, using Posilac makes sense because it has been shown to be an effective tool for increasing milk production, said Terry Lehenbauer, associate director of the University of California's Veterinary Medicine Teaching and Research Center in Tulare, Calif.

"From that perspective, I think it still has a place," Lehenbauer said. "It's just that in our current times and our current market situation, there's not an urgent need to produce more milk at the moment. But in the long term, the dairy industry needs to be productive and efficient. I think (Posilac) can contribute to that."

A growing dislike among consumers -- and some foreign governments -- of the use of hormone additives has soured many dairy farmers' taste for using Posilac, whose generic name is recombinant bovine somatotropin, or rBST.

The compound supplements a cow's natural levels of somatotropin, essentially causing dairy cows to eat more feed and produce more milk, Lehenbauer said.

The technology was developed in the 1980s and became available in the 1990s. Only one product was approved for use by the U.S. Food and Drug Administration -- Posilac, which was introduced by Monsanto and later sold to Elanco Animal Health.

Elanco's website describes Posilac as aiding "production practices that help dairy farmers increase milk production using fewer natural resources." It asserts the FDA's approval of the drug "required a stringent regulatory risk assessment to ensure human, animal and environmental safety."

At one time, Posilac was one of the largest-selling dairy animal pharmaceutical products in the U.S. The product "enjoyed a very favorable market and distribution and was widely used in the United States," Lehenbauer said.

Over time, though, some segments of the dairy industry began to try to distinguish themselves by not supplementing cows, he said. Many companies began restricting use of the product by the dairies that provided their milk, and some imposed financial penalties for milk that was produced using the technology, he said.

Internationally, concerns about rBST's impact on animal welfare have caused trading partners such as Canada and the European Union to severely restrict it.

One study in the European Union in 1999 linked long-term use of rBST to an increased risk of clinical mastitis, an increased incidence of foot and leg disorders and adverse effects on reproduction.

"These are problems which would not occur if BST were not used and often results in unnecessary pain, suffering and distress," concluded the study by the EU's Scientific Committee on Animal Health and Animal Welfare.

The milk produced by cows supplemented with the synthetic hormone is identical to that from other cows, scientists say.

Scientists "could not take milk from a supplemented cow and be able to confidently distinguish it from cows that were not supplemented," said Lehenbauer, who is part of a multi-university study of the potential for genetic resistance to bovine respiratory disease.

Worries about Posilac in Europe were based on "misinformation" and the perceived impacts on human health "really are not true," said Michael Marsh, CEO of Western United Dairymen.

Still, the use of Posilac by American dairymen has fallen off. In the Tulare area, a large majority of dairies used it at its peak, Lehenbauer said. Today, 10 percent or less of the dairies use it, he said.

The decline in its use in recent years likely minimized the decline in milk prices, as a slight decrease in the supply of milk helped edge prices up, he said.

"The U.S. and California dairy industries are very capable of supplying milk," he said. "Historically, it's been very easy for the dairy industry to overproduce milk for periods of time in excess of the market demand, which is what causes prices to drop so badly."

In the future, however, the use of Posilac will make sense "because it has been shown scientifically to be an effective tool for increasing milk production," Lehenbauer said. "So again overall, it allows us to produce more milk with fewer resources."

Marsh believes the drug may already be making a comeback.

"I think its use is probably a bit more prevalent today than it was during the nadir of its use," he said. "I think as farmers have come to understand there's more and more pressure ... to reduce environmental impact, more farmers have looked at that as an important tool to assist them in doing so."

The challenge will be to provide consumers with scientifically correct information about the safety of milk from cows who've received rBST, Lehenbauer said.

"It's an ongoing effort because consumers do tend to be concerned about the wholesomeness and safety of their food supply," he said. "It takes an effort by the dairy industry ... to provide assurance that consumers need when they consider using these types of modern technologies."


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