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Home / Equine Research Bank / Ir Vet J / Sporadic worldwide “clusters” of feed driven Zil...
Irish veterinary journal2022; 75(1); 11; doi: 10.1186/s13620-022-00215-8

Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis.

Abstract: Zilpaterol is a β2-adrenergic agonist medication approved in certain countries as a cattle feed additive to improve carcass quality. Trace amounts of Zilpaterol can transfer to horse feed, yielding equine urinary "identifications" of Zilpaterol. These "identifications" occur because Zilpaterol is highly bioavailable in horses, resistant to biotransformation and excreted as unchanged Zilpaterol in urine, where it has a 5 day or so terminal half-life.In horses, urinary steady-state concentrations are reached 25 days (5 half-lives) after exposure to contaminated feed. Zilpaterol readily presents in horse urine, yielding clusters of feed related Zilpaterol identifications in racehorses. The first cluster, April 2013, involved 48 racehorses in California; the second cluster, July 2013, involved 15 to 80 racehorses in Hong Kong. The third cluster, March 2019, involved 24 racehorses in Mauritius; this cluster traced to South African feedstuffs, triggering an alert concerning possible Zilpaterol feed contamination in South African racing. The fourth cluster, September/October 2020 involved 18 or so identifications in French racing, reported by the French Laboratories des Courses Hippiques, (LCH), and in July 2021, a fifth cluster of 10 Zilpaterol identifications in South Africa.The regulatory approach to these identifications has been to alert horsemen and feed companies and penalties against horsemen are generally not implemented. Additionally, given their minimal exposure to Zilpaterol, there is little likelihood of Zilpaterol effects on racing performance or adverse health effects for exposed horses.The driving factor in these events is that Zilpaterol is dissolved in molasses for incorporation into cattle feed. Inadvertent incorporation of Zilpaterol containing molasses into horse feed was the source of the California and Hong Kong Zilpaterol identifications. A second factor in the 2019 Mauritius and 2020 French identifications was the sensitivity of testing for Zilpaterol in Mauritius and France, with the French laboratory reportedly testing at a "more sensitive level for Zilpaterol". As of January 1, 2021, the new FEI Atypical Finding (ATF) policy specifies Zilpaterol as a substance to be treated as an Atypical Finding (ATF), allowing consideration of inadvertent feed contamination in the regulatory evaluation of Zilpaterol identifications.
© 2022. The Author(s).
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Publication Date: 2022-05-14 PubMed ID: 35568924PubMed Central: PMC9107120DOI: 10.1186/s13620-022-00215-8Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The article reviews incidents of Zilpaterol detection in racehorses. Zilpaterol, a cattle feed additive, sometimes makes its way into horse feed. Its detection in horse urine has led to a series of “clusters” of Zilpaterol identifications in racehorses across the globe.

Research Background

  • Zilpaterol is a β2-adrenergic agonist drug that is used in some countries to improve the quality of cattle carcass. It is highly bioavailable in horses and is excreted as unchanged Zilpaterol in horse urine.
  • Studies indicate that Zilpaterol can indeed get transferred to horse feed via contamination, which subsequently leads to the detection of the drug in horse urine.
  • The drug is resistant to biotransformation and has a terminal half-life in horses of approximately five days, reaching urinary steady-state concentrations about 25 days after ingestion through contaminated feed.

Zilpaterol Clusters in Racehorses

  • The core of this study revolves around the global “clusters” of feed driven Zilpaterol identifications in racing horses, beginning in April 2013 with 48 cases in California.
  • Subsequent clusters occurred in July 2013 involving 15 to 80 racehorses in Hong Kong; March 2019 with 24 racehorses in Mauritius; September/October 2020 with around 18 identifications in France and most recently, July 2021 with 10 new cases in South Africa.
  • The 2019 cluster in Mauritius could be traced back to South African feedstuffs, thereby sounding an alarm about possible Zilpaterol feed contamination in South African racing.

Impact and Regulatory Response

  • Despite the identifications, there has been no severe penalty directed towards horsemen and feed companies, given the accidental nature of Zilpaterol contamination. It was also recognized that the minimum exposure to Zilpaterol posed little threat to the horses’ health or their racing performance.
  • Zilpaterol contamination mainly occurred due to the inadvertent inclusion of Zilpaterol-infused molasses into horse feed as seen in the California and Hong Kong “clusters”.
  • The 2019 and 2020 Zilpaterol clusters in Mauritius and France were caused due to a second factor – the enhanced sensitivity of Zilpaterol testing in these countries, with France’s test being “more sensitive”.
  • As a new regulation, since January 1, 2021, the FEI Atypical Finding (ATF) policy has considered Zilpaterol a substance to be treated as an ATF, thus acknowledging the potential for unintentional feed contamination in any investigation of Zilpaterol detection.

Cite This Article

APA
Machin J, Brewer K, Morales-Briceno A, Fenger C, Maylin G, Tobin T. (2022). Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis. Ir Vet J, 75(1), 11. https://doi.org/10.1186/s13620-022-00215-8

Publication

Irish veterinary journal
ISSN: 2046-0481
NlmUniqueID: 0100762
Country: Ireland
Language: English
Volume: 75
Issue: 1
Pages: 11
PII: 11

Researcher Affiliations

Machin, Jacob
  • Department of Toxicology and Cancer Biology and the Maxwell H. Gluck Equine Research Center, Dept. of Veterinary Science, University of Kentucky, Lexington, KY, 40546, USA.
Brewer, Kimberly
  • , 15775 Cypress Creek Lane, Wellington, FL, 33414, New Zealand.
Morales-Briceno, Abelardo
  • ALSHULA Pharmacy-Veterinary Technical Support, Doha, Qatar.
Fenger, Clara
  • Equine Integrated Medicine, 4904 Ironworks Rd, Georgetown, KY, 40324, USA.
Maylin, George
  • New York Drug Testing and Research Program, 777 Warren Rd Ithaca, New York, NY, 14853, USA.
Tobin, Thomas
  • Department of Toxicology and Cancer Biology and the Maxwell H. Gluck Equine Research Center, Dept. of Veterinary Science, University of Kentucky, Lexington, KY, 40546, USA. ttobin@uky.edu.

Conflict of Interest Statement

The authors cite no competing interests or specific funding other than those referenced in acknowledgements. All authors contributed to the review, analysis and drafting of the manuscript and all reviewed and approved the final product for publication. Authors JJM, KB, CF, AMB, GAM and TT are researchers and participants in areas of equine forensic science and have presented and at times testified as experts such matters. The corresponding author, TT, has at times advised parties with respect to matters involving Zilpaterol identifications.

References

This article includes 41 references
  1. Montgomery JL, Krehbiel CR, Cranston JJ, Yates DA, Hutcheson JP, Nichols WT, Streeter MN, Bechtol DT, Johnson E, TerHune T, Montgomery TH. Dietary zilpaterol hydrochloride. I. Feedlot performance and carcass traits of steers and heifers.. J Anim Sci 2009 Apr;87(4):1374-83.
    doi: 10.2527/jas.2008-1162pubmed: 19098247google scholar: lookup
  2. Costello M. IHRB confirms French lab is 'operating to a more sensitive level for zilpaterol' [Internet]. 2020 [cited 2020Nov16]. Available from: https://www.theirishfield.ie/ihrb-confirms-french-lab-is-operating-to-a-more-sensitive-level-for-zilpaterol-577878/
  3. Zilmax (zilpaterol hydrochloride) - Consumer Information Center [Internet]. Zilmax. Merck; 2015 [cited 2020Nov16]. Available from: http://www.zilmax.com/
  4. Brewer K, Dirikolu L, Hughes CG, Tobin T. Scopolamine in racing horses: trace identifications associated with dietary or environmental exposure.. Vet J 2014 Mar;199(3):324-31.
    doi: 10.1016/j.tvjl.2013.12.013pubmed: 24440440google scholar: lookup
  5. Tobin T, Dirikolu L, Brewer K, Hughes CG. A clinician's guide to factors affecting withdrawal times for equine therapeutic medications.. Vet J 2013 Nov;198(2):313-21.
    doi: 10.1016/j.tvjl.2013.07.002pubmed: 23932745google scholar: lookup
  6. Tobin T, Stirling KH, Brewer K. World rules for equine drug testing and therapeutic medication regulation: 2012 policy of the national Horsemen's Benevolent and Protective Association, Inc.. Nicholasville, KY: Wind Publications; 2012.
  7. World Health Organization. World Health Organization; 2019 [cited 2020Nov16]. Available from: https://apps.who.int/food-additives-contaminants-jecfa-database/chemical.aspx?chemID=6191
  8. Lehner AF, Harkins JD, Karpiesiuk W, Woods WE, Robinson NE, Dirikolu L, Fisher M, Tobin T. Clenbuterol in the horse: confirmation and quantitation of serum clenbuterol by LC-MS-MS after oral and intratracheal administration.. J Anal Toxicol 2001 May-Jun;25(4):280-7.
    doi: 10.1093/jat/25.4.280pubmed: 11386642google scholar: lookup
  9. Dirikolu L, Mollett BA, Troppmann A, Woods WE, Bratton C, Cashman CP, Schroedter D, Mayer B, Lehner AF, Karpiesiuk W, Hughes C, Boyles J, Harkins JD, Tobin T. Apparent ELISA detection times for albuterol after administration with the torpex equine inhaler device.. Vet Ther 2002 Fall;3(3):297-307.
    pubmed: 12447838
  10. Shelver WL, Thorson JF, Hammer CJ, Smith DJ. Depletion of urinary zilpaterol residues in horses as measured by ELISA and UPLC-MS/MS.. J Agric Food Chem 2010 Apr 14;58(7):4077-83.
    doi: 10.1021/jf904253tpubmed: 20218607google scholar: lookup
  11. Shelver WL, Smith DJ. Tissue residues and urinary excretion of zilpaterol in sheep treated for 10 days with dietary zilpaterol.. J Agric Food Chem 2006 Jun 14;54(12):4155-61.
    doi: 10.1021/jf060552mpubmed: 16756341google scholar: lookup
  12. Smith DJ, Shelver WL, Chakrabarty S, Hoffman TW. Detection and quantification of residues in sheep exposed to trace levels of dietary zilpaterol HCl.. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2019 Sep;36(9):1289-1301.
    doi: 10.1080/19440049.2019.1627005pubmed: 31219730google scholar: lookup
  13. Shelver WL, Smith DJ. Immunochemical-based zilpaterol measurement and validation in urine and tissues. Food and Agricultural Immunology 2011;22(3):247–58.
    doi: 10.1080/09540105.2011.565038google scholar: lookup
  14. Wagner SA, Mostrom MS, Hammer CJ, Thorson JF, Smith DJ. Adverse Effects of Zilpaterol Administration in Horses: Three Cases. Journal of Equine Veterinary Science 2008;28(4):238–43.
    doi: 10.1016/j.jevs.2008.02.006google scholar: lookup
  15. Dunne A. An iterative curve stripping technique for pharmacokinetic parameter estimation.. J Pharm Pharmacol 1986 Feb;38(2):97-101.
    doi: 10.1111/j.2042-7158.1986.tb04519.xpubmed: 2870170google scholar: lookup
  16. Cronin N. Zilpaterol Feed Contamination Update [Internet]. Irish Horseracing Regulatory Board (I.H.R.B). 2020 [cited 2020Nov20]. Available from: http://www.ihrb.ie/general-press-releases/zilpaterol-feed-contamination-update-2
  17. Yuv Y. COMMUNIQUE - ZILPATEROL INQUIRY (22.03.2019). The Mauritius Turf Club 2019.
  18. Forensic Toxicology [Internet]. QuantiLAB. QuantiLAB; 2020 [cited 2020 Nov20]. Available from: http://quantilab.mu/Services/Analytical-Testing/Forensic-Toxicology
  19. https://www.sportingpost.co.za/2021/07/santa-shock-at-nha-snub-of-ifha-recommendation/
  20. https://www.racingpost.com/news/all-obrien-family-horses-to-be-withdrawn-from-longchamp-on-sunday/453218
  21. Arcella D, Baert K, Binaglia M, Gervelmeyer A, Innocenti ML, Ribo O, Steinkellner H, Verhagen H. Review of proposed MRLs, safety evaluation of products obtained from animals treated with zilpaterol and evaluation of the effects of zilpaterol on animal health and welfare. European Union Joint Expert Committee on Food Additives [JECFA] V14 Issue 9 2016.
    doi: 10.2903/j.efsa.2016.4579google scholar: lookup
  22. . Positive Zilpaterol Tests Cleared, Feed Contamination Cited. 2013 Mar 27.
  23. . Zilpaterol in Purina Horse Feed in California. Horse Authority 2013 Mar 29.
  24. . Hong Kong Positives Due to Contaminated Feed. Bloodhorse 2016 Jun 2.
  25. Aitken A. 17 Hong Kong horses test positive for drugged feed as zilpaterol found in 2nd brand. 2013 Jun 13.
  26. De Chalain S. Accueil. 2019 Mar 22.
  27. http://www.mauritiusturfclub.com/index.php/en/latest-news/local/17382-communique-25-11-19-zilpaterol-warning
  28. Govender T. CAUTIONARY NOTICE: ZILPATEROL. National Horseracing Authority 2019.
  29. Owner - 'NHRA Feeding Us Waffle?' [Internet]. Sporting Post. Sporting Post ; 2019 [cited 2020Nov20]. Available from: https://www.sportingpost.co.za/2019/11/nhra-zilpaterol-warning/
  30. . Zilpaterol found in biological samples taken from horses. 2020 Oct 2.
  31. . Zilpaterol feed contamination: Latest updates and advice. The British Horseracing Authority 2020 Oct 20.
  32. . GAIN EQUINE NUTRITION UPDATE – 14th OCTOBER. 2020 Oct 14.
  33. . BETA Update: Zilpaterol contamination in equine feedstuffs. .
  34. Cronin N. Zilpaterol Feed Contamination Update. 2020 Oct 16.
  35. https://www.scmp.com/sport/racing/article/1280487/ricky-yiu-escapes-punishment-zilpaterol-positives
  36. http://www.mauritiusturfclub.com/index.php/actualites/locales/14855-communique-zilpaterol-inquiry-22-03-2019
  37. https://www.bloodhorse.com/horse-racing/articles/122207/chrb-dismisses-positives-cites-contamination
  38. https://www.horsetalk.co.nz/2020/10/24/doping-moratorium-equestrian-molasses-contamination/
  39. . FEI Online General Assembly 2020 Rules Sesson. Inside FEI 2020.
  40. . Zilpaterol RASFF & Follow up: DAFM (Irish Dept of Ag, Food & Marine) updated members states at the February SCoPAFF. .
  41. https://www.beta-uk.org/pages/news-amp-events/news/beta-update-zilpaterol-contamination-in-equine-feedstuffs..php

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