Zilpaterol fallout - isn't it time for a European wide threshold testing protocol?
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By Alysen Miller
It was a cruel twist of fate, in a year already overshadowed by the spectre of COVID 19, when another biosecurity scare threatened to cast the longest shadow over the blighted 2020 racing season.
On the eve of its biggest racing weekend of the year, French racing authority France Galop announced that five horses had recently tested positive for zilpaterol, a synthetic substance used to promote muscle growth in beef cattle, which is licenced in the United States and other countries for agricultural use but widely banned in Europe. The common denominator was quickly determined to be their feed: all the positive samples were taken from horses fed on Gain Equine Nutrition—the equine feed brand of Glanbia, an Ireland-based global nutrition group with operations in 32 countries. Irish trainer Aidan O’Brien and his two sons, Joseph and Donnacha, who use Gain products, were forced to withdraw all of their runners from Longchamp, including four horses that were due to run in the Prix de l’Arc de Triomphe.
The culprit turned out to be a contaminated feed ingredient—cane molasses, which was supplied to Gain by a third-party supplier, ED&F Man Liquid Products. (Since then, it has been confirmed by the British Equestrian Trade Association that cane molasses containing Zilpaterol supplied by ED&F Man had been supplied to a further half-dozen feed companies in the UK, although at lower levels than was the case in Ireland.) But the scandal has massive implications for the industry beyond O’Brien’s four non-runners in the €5 million European showpiece and raises questions about biosecurity and testing procedures in general, as well as about the sensitivity and specificity of testing apparatus across different racing jurisdictions, both in Europe and beyond.
What is zilpaterol?
But first, it’s worth explaining what exactly zilpaterol is and how it could have found its way into horse feed. Zilpaterol is a beta-agonist used to increase the size of cattle and the efficiency of feeding them. As of October 2017, it is approved by the Food and Drug Administration in the United States, as well as some 16 other countries, for use in beef cattle; although it has rather fallen out of favour in recent years as many of the countries to which the US exports, including China, do not permit it. It is also strictly prohibited in the European Union. As an anabolic steroid, it is widely banned for use in horses due to its potential performance enhancing properties. “The problem is that the feed manufacturers had no way of predicting this was going to happen,” says Joe Pagan of Kentucky Equine Research. Because of zilpaterol’s declining popularity in the beef industry, in other words, it is not necessarily something that would be on their radar: “It’s so completely out of left field that it’s not something that they would have thought to test for,” he adds.
Nevertheless, questions remain about how exactly a prohibited substance was able to enter the food chain. Feed manufacturers generally go to great lengths to ensure that their product is safe and free of contaminants by testing a certain proportion of their product before sending it to market—for example, a 300gm sample from each 10 tonne batch. Furthermore, feed manufacturers in the UK and Ireland are subject to the Universal Feed Assurance Scheme (UFAS), which regularly audits a company’s entire operations to ensure that they are in compliance with biosecurity protocols. However, several feed industry representatives, who declined to be quoted in this article, privately acknowledge the reality that it is simply too expensive to test every bag, and occasionally something will slip through the net. Many may remember that in 2014, a batch of Dodson & Horrell feed was contaminated by poppy seeds that had been grown in a field close to their plant, resulting in five horses testing positive for morphine (among them, embarrassingly, the Queen’s Royal Ascot Gold Cup heroine, Estimate). Prior to that, in a long-running legal battle, the Willie Mullins-trained Be My Royal was disqualified after winning the 2002 Hennessy Cognac Gold Cup, the highest-profile casualty among a glut of failed morphine tests at the time.
Test & Trace
O’Brien’s Irish Derby winner Sovereign.
A further difficulty for feed manufacturers is that, even with the most stringent testing regime in place, identifying a possible contaminant among a batch of feed is rather like finding the proverbial needle in a haystack. “How do you test 25,000 tonnes of oats for a poppyseed?” Poses biochemist and equine nutritionist Jim Fielden. “One handful can differ from another handful. You pick up one handful and it’s clear; the next handful has one seed in it, and you’ve got a problem. You will never get an exact reading of both handfuls coming from the same sack.” Furthermore, depending on supply chains and the length of time between contamination, production and ingestion, there is no guarantee that a hormone such as zilpaterol would have been detectable in the feed before it had made its way into the horse. “Zilpaterol, if it’s exposed to air conditions, can degrade within a certain time,” explains Fielden. “If they have not analysed it straight from the bin, within a certain length of time, it might prove negative. When it gets into the body, that hormone works with the rest of the hormone system and that’s why it’s easier to find.” In other words, it’s possible that, in some cases, the only way of knowing if zilpaterol was present is if it shows up in the horse as a positive test.
Specificity & Sensitivity
Aidan O’Brien and his sons, were forced to withdraw all of their runners from Longchamp.
And yet there had been no positive tests for zilpaterol anywhere in Europe until France Galop made its bombshell announcement on October 2nd. The Irish Horseracing Regulatory Board tests all winners on its tracks as a matter of course. Is it conceivable that horses exposed to the contaminated feed could pass a test in Ireland only to fail in France? Of O’Brien’s four intended Arc runners—Mogul, Serpentine, Japan, and Sovereign—Japan and Sovereign had run in Ireland within three weeks of the Arc. Neither had won. The O’Brien family did, however, send out multiple winners in Ireland during the same period; and yet in that period, and despite the fact that the contaminated molasses had made its way to several feed companies the UK by this time, there had only been positives detected under the rules of racing in France from feed originating from one Irish company. …
