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

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 hi...

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Autores principales: Machin, Jacob, Brewer, Kimberly, Morales-Briceno, Abelardo, Fenger, Clara, Maylin, George, Tobin, Thomas
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9107120/
https://www.ncbi.nlm.nih.gov/pubmed/35568924
http://dx.doi.org/10.1186/s13620-022-00215-8
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author Machin, Jacob
Brewer, Kimberly
Morales-Briceno, Abelardo
Fenger, Clara
Maylin, George
Tobin, Thomas
author_facet Machin, Jacob
Brewer, Kimberly
Morales-Briceno, Abelardo
Fenger, Clara
Maylin, George
Tobin, Thomas
author_sort Machin, Jacob
collection PubMed
description 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(st), 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.
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spelling pubmed-91071202022-05-15 Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis Machin, Jacob Brewer, Kimberly Morales-Briceno, Abelardo Fenger, Clara Maylin, George Tobin, Thomas Ir Vet J Review 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(st), 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. BioMed Central 2022-05-14 /pmc/articles/PMC9107120/ /pubmed/35568924 http://dx.doi.org/10.1186/s13620-022-00215-8 Text en © The Author(s) 2022 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visithttp://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.
spellingShingle Review
Machin, Jacob
Brewer, Kimberly
Morales-Briceno, Abelardo
Fenger, Clara
Maylin, George
Tobin, Thomas
Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis
title Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis
title_full Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis
title_fullStr Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis
title_full_unstemmed Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis
title_short Sporadic worldwide “clusters” of feed driven Zilpaterol identifications in racing horses: a review and analysis
title_sort sporadic worldwide “clusters” of feed driven zilpaterol identifications in racing horses: a review and analysis
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9107120/
https://www.ncbi.nlm.nih.gov/pubmed/35568924
http://dx.doi.org/10.1186/s13620-022-00215-8
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