The National Horsemen's Horsemen's Benevolent and Protective Association, given the results of a recent study, has suggested research into medication thresholds and withdrawal times be performed using horses in training.The National HBPA Medication Committee, which met in Oregon in late July, said a study performed by Dr. Rick Arthur and Dr. Scott Stanley in California disputed the results of an unpublished study that established a threshold level for clenbuterol of 10 picograms--parts per trillion--in serum with a four-day withdrawal time. The study was performed using horses with an unknown exercise status.The study by Arthur and Stanley employed horses trained by Richard Mandella in Southern California. Of the 19 horses treated with clenbuterol for 10 days at the lowest recommended dose, three were above 10 picograms after five days. However, all 19 horses were found to be below a 25-picogram threshold as early as 72 hours after administration of the drug.There has been debate among members of the Racing Medication and Testing Consortium as to a threshold level and withdrawal time for clenbuterol, a therapeutic medication used in racehorses."This valuable research clearly illustrates that all thresholds should be established using significant numbers of horses in training to avoid inadvertent positives," Kent Stirling, executive director of the Florida HBPA who heads the Medication Committee, said in an Aug. 19 release.In another matter, National HBPA general counsel Doug McSwain told the Medication Committee industry policymakers should apply a model for determining the correct level for therapeutic medication thresholds by using the Dauber Challenge, which established guidelines for federal courts to follow for the admission of scientific evidence and testimony.McSwain said appropriate thresholds must be based on the best level of scientific knowledge available. The Daubert principles ask whether a scientific proposition is testable or has been tested; whether it has been subjected to peer review and publication; whether the methodology or technique used in analyzing it has a known error rate; and whether the methodology and proposition has general acceptance in the scientific community.Meanwhile, Stirling said the Medication Committee expressed concern over suspension of the drug research program at the Gluck Equine Research Center in Lexington. The program was headed by Dr. Thomas Tobin, who serves as an adviser to the National HBPA on medication and testing issues.Funding for the program was pulled this spring, and there has been no word about its reinstatement. The Kentucky Equine Drug Research Council, which hasn't met since last October and has no members because their terms expired Aug. 1, clashed with Tobin from time to time over research and its costs.The National HBPA, in its release, said it supports Gluck research on threshold levels for therapeutic medication."The research at the Gluck Center has made tremendous contributions to the horse industry both in Kentucky and nationally--even internationally," Stirling said in the release. "The Gluck Center's research on furosemide led to appropriate conditions for its use which are now in place throughout the United States. The Center developed the application of the ELISA tests in racing, which brought the Neogen Corp. to Lexington, creating approximately 100 jobs and adding roughly $30 million to the Kentucky economy annually. "In addition, the Gluck Center recently established a use patent for Toltrazuril, an EPM treatment, that has been licensed to Bayer Animal Health, as well as having other patents in progress for other therapeutics. Moreover, the Gluck Center pioneered the use of 'no-effect thresholds' for therapeutic medications, which has caught on nationally and internationally for the regulation of therapeutic medications and has led to a decline in positive tests for horsemen for inadvertent detections which had no pharmacological effect on the horse."