US breeder introduces initiative to show its yearlings are free of bisphosphonates


A major thoroughbred breeder in the United States has introduced an innovative testing protocol to reassure potential buyers that bisphosphonates are not used in its growing horses.

Stonestreet Farm’s blood sampling, testing, and secure storage protocol, in partnership with the University of Kentucky’s Gluck Equine Research Center, was developed in response to reports of off-label bisphosphonate use in young horses in the racing industry.

Bisphosphonates are used to treat older horses with symptoms of navicular syndrome and some other bone conditions. They are FDA-approved only for use in horses aged four years or older. They are not approved for use in pregnant or lactating mares because questions remain over potential effects on foal development.

Bisphosphonates reduce the action of osteoclasts, cells which clear away damaged bone and make way for the development of new bone. In young horses, this could interfere with growth.

Concerns have been raised in the racing industry over off-label use in young horses, apparently in the belief it will help build stronger bones.

Stonestreet’s initiative is intended to reassure buyers that its young stock have not been exposed to

Buyers of yearlings it has bred and raised will have an opportunity to review a blood-health window of at least six months before their purchase. Buyers can also avail themselves of post-sale testing offered by auction houses.

“Last year we raised and sold nearly $US20 million of yearlings but our focus has always been to raise racehorses, not sale horses,” said Barbara Banke, owner of Stonestreet Farm.

“We are proud of what we do and I think transparency in raising a racehorse is so important. We want our buyers to have the utmost confidence in our yearlings.”

“We invite everyone to join us, because demonstrating that we breed and raise the healthiest and strongest racehorses is not only good for our business, it’s good for the entire sport.”

During 2019, blood samples were drawn from each Stonestreet yearling on a regular schedule developed by the Gluck Equine Research Center using current bisphosphonate detection periods. These were drawn by a third-party veterinarian experienced in handling samples within a regulatory environment who was hired by the Gluck Equine Research Center.

Sample collection was supervised by Dr Scott Stanley, professor of analytical chemistry at the Gluck Equine Research Center, who ensured a strict chain-of-custody and authored documentation connecting each sample to the yearling from which it was taken.

Samples were stored and frozen in accordance with the normal regulatory laboratory standards established for pre and post-race blood samples in a dedicated freezer.

The samples were tested by Gluck for bisphosphonates and anabolic steroids.

The buyer of any Stonestreet-bred and raised yearling in 2019 may request a report stating the test results for the individual that they purchased.

Further, at their own expense, they may also request testing for anabolic steroids and/or bisphosphonates on the blood samples which remain in secure storage at the Gluck Equine Research Center.

Purchasers have the opportunity to request any additional testing during the seven days following the fall of the hammer by completing the Request to Test form available on the Stonestreet website.

Following completion of the secure storage period, the blood samples will be donated to Gluck and used in research projects.

“We applaud Stonestreet’s efforts to employ an approach driven by transparency and good science as part of their sales operation,” said Nancy Cox, dean of the University of Kentucky’s College of Agriculture, Food and Environment.

“We look forward to further results of this project as time goes on.

“This kind of project is what we do best, to merge our college’s scientific capacity with a worthy industry goal. It also displays our commitment to safety in all aspects of the equine industry.”

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