05/09/2013 1:48PM

Established feed supplements can help avoid positive drug tests

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It’s the stuff of nightmares for any trainer: A horse grabs a bite of poppy-seed bagel, a batch of bedding straw contains a little jimsonweed, or a new feed supplement turns out to be loaded with caffeine even though that’s not on the label, and the trainer ends up with a positive drug test.

California horsemen got a sharp reminder of the dangers of contamination in March, when contaminated Purina horse feed caused 48 positive tests for the Class 3 drug zilpaterol, prompting the California Horse Racing Board to ban Purina feed from the state’s racetracks for a week. Zilpaterol is used to promote growth in cattle but can have adverse side-effects in horses, including muscle tremors and rapid heart rate.

In this instance, there was little trainers could have done to avoid accidental positives. The drug entered the equine food chain through molasses that another company had supplied to Purina, and the CHRB dismissed the resulting positive tests.

But horsemen can take some steps to prevent contamination and accidental positives, said Dr. Scott Stanley, professor of equine analytical chemistry at the University of California-Davis.

“One of the approaches you can take is to stick with the known, named products,” Stanley said. “Generally, the major feed companies do a good job. Someone just walking around selling their own stuff that they say they’ve determined is good stuff, that’s probably really dangerous. There’s not any requirement that it’s tested, we don’t know what products or materials they’ve used to develop it, and the potential is that there are contaminants or other problematic things. It’s also more likely that it changes batch to batch.

“The other thing to do is to stay away from anything that is developed or designed for human consumption, because the rules are different for humans than for veterinary medicine. We all start our day with a load of caffeine, but that’s not permitted for horses. In addition to that, all the over-the-counter medications that we take, like ephedrine or pseudoephedrine, those are all part and parcel of our normal environment. We don’t think twice about taking Robitussin if we have a little cold, but all of those things result in positives for horses.”

Feed supplements and compounded pharmaceuticals can pose a particular problem.

“Those things are completely unregulated, and nutraceuticals are also completely unregulated,” Stanley said. “So, if my friend and I get some space together and start developing a formula for a nutraceutical product, and we give it a fancy name and promote it, I can sell as much of that as I want. There’s no oversight.”

Dr. Steve Duren, an equine nutritionist and equine exercise physiologist who owns Performance Horse Nutrition in Idaho, noted that trainers should look for products from companies that are familiar with their particular sport – in this case, racing.

“If you choose to use some of the different herbal products from manufacturers that are not aware of the rules of racing, your chances of contamination are actually quite high,” Duren said. “A lot of substances that are in those are on the banned-substances list, and because those people don’t usually sell into the racing jurisdictions, they either have no knowledge of it or make no effort to ensure they’re not there.

“Most of the racehorse trainers I consult for don’t use those types of products, or, if they do, they actually have checked with their veterinarian or equine nutritionist to make sure the products are free of prohibited substances. I would make sure that manufacturer has had the product tested by a lab to make sure that it’s free of prohibited substances, and I’d further ask that they have a letter certifying that it was tested on this date and that it’s free of these substances.”

Stanley recalled a trainer who had used a supplement on his horses after seeing that the label said “no caffeine added.”

“But on the label, it said it had guarana root, which is loaded with caffeine,” Stanley said. “So, he felt he was giving something that didn’t have caffeine, but the company was saying they didn’t add any extra caffeine.”

Duren noted that feed and supplements are much more tightly regulated in other jurisdictions, most notably Japan and Hong Kong, something Duren thinks is a good idea. “A feed manufacturer has to routinely have their feed screened by the racing authorities to make sure that it’s free of these substances,” Duren said, “so they’re much more aggressive than in the United States. Here, we have a tendency to wait and get a positive test and then backtrack to figure out where it came from. In Japan and Hong Kong, before you can even sell your feed at a racetrack, it’s tested.

“I do think that if you’re going to sell a supplement on the racetrack, there should be some uniform testing that it has to go through at least once a year that you’re complying with and that the product’s been tested and checked out,” Duren added. “That way, it gives trainers a list of supplement manufacturers with products that have been tested and are free of potential problems.”

Stanley believes regulation would be helpful in the field of supplements, too. “I totally think that it would protect horsemen and the industry quite a bit if there were more regulations on both nutraceuticals and compounded pharmaceuticals,” he said.

“The other major ingredient that a horse eats – besides grain, which has lots of quality-control measures – is the forage component of their diet, the hay,” Duren said. “There’s no quality control on that.”

Weeds and flowers in hay or straw bedding can cause positive drug tests, and the advice here is to go with reputable suppliers. But Duren points out that it’s nearly impossible to ensure that a bale of hay or straw is completely free of contaminants.

Grooms or other stable staff with drug problems also can accidentally pass drugs into a horse’s system, via tongue ties, for example. One of the things trainers can do to protect themselves is to ask their employees to take a pre-hiring drug test or request help from the racing commission to spot-check for drug use, Stanley said.

As for the occasional contamination via candy bar, poppy-seed muffin, or coffee spilled on a horse’s stall ledge, Stanley said: “It’s all about good housekeeping. If you instruct your people not to share these things or expose the horses to them, then generally it doesn’t happen.”

Pharmacological effects from natural ingredients

Thinking of adding a natural feed supplement to your horse’s diet? Many drugs are derived from natural ingredients, and some ingredients can result in a positive drug test – even though the drug they contain is not specifically listed on a supplement’s label. Before feeding any supplement, it’s worth checking for ingredients, such as the ones listed below, that can cause an inadvertent positive.

Caffeine (xanthine alkaloids) – Kola nut, coffee beans, guarana root, yerba mate, yaupon holly
Cannabis (marijuana) – Hemp
Cocaine – Coca plant
Digitalis – Foxglove
Ephedrine (ephedra) – Ma Huang
Nicotine – Nightshade family of plants, tobacco
Morphine – Opium poppy
Quinine – Cinchona bark
Reserpine – Rauwolfia serpentina
Salicylate – Willow bark, meadow sweet