US pork producers have debuted a label that assures consumers their meat was not made by giving animals ractopamine, an asthma drug-like beta agonist that increases protein synthesis. The ractopamine molecule is a mixture of mirror-image "stereoisomers," which are discouraged in medicines because of unpredictability.
Ractopamine is considered a "repartitioning agent" and was recruited for livestock use when asthma researchers found the drug made mice more muscular says Beef magazine. It is marketed as Paylean for pigs, Optaflexx for cattle and Topmax for turkeys and used in 45 percent of US pigs, 30 percent of ration-fed cattle and in turkeys.
Three years after Paylean's 1999 approval, the FDA's Center for Veterinary Medicine's Office of Surveillance and Compliance accused Elanco, which was Eli Lilly's animal drug division at the time, in a warning letter of withholding information about "safety and effectiveness" and "adverse animal drug experiences" upon which ractopamine was approved.
"Our representatives requested a complete and accurate list of all your GLP [Good Laboratory Practices] studies involving Paylean (Ractopamine hydrochloride), including their current status as well as the names of the respective study monitors. In response, your firm supplied to our representatives multiple lists which differed in the names of the studies and their status. In addition, your firm could not locate or identify documents pertaining to some of the studies. This situation was somewhat confusing and created unneeded delays for our representatives," wrote Gloria J. Dunnavan, Director Division of Compliance.
Omitted said the FDA were calls from farmers reporting "hyperactivity," "dying animals," "downer pigs" and "tying up" and "stress" syndromes to Elanco, said the FDA. Elanco also received calls from farmers saying that "animals are down and shaking," and reporting "pig vomiting after eating feed with Paylean," accused the FDA.
According to Temple Grandin, Professor of Animal Science at Colorado State University, the "indiscriminant use of Paylean (ractopamine) has contributed to an increase in downer non-ambulatory pigs," and pigs that "are extremely difficult to move and drive." In Holsteins, ractopamine is known for causing hoof problems, says Grandin and feedlot managers report the "outer shell of the hoof fell off" on a related beta agonist drug, zilpateral marketed as Zilmax.
An article in the 2003 Journal of Animal Science confirms that "ractopamine does affect the behavior, heart rate and catecholamine profile of finishing pigs and making them more difficult to handle and potentially more susceptible to handling and transport stress."