Last week, horsemen stabled at Gulfstream Park and Palm Meadows received a text message alerting them to a new policy by The Stronach Group to ban from its stable area injectable products containing iron.
Bill Badgett, executive director of Florida operations for The Stronach Group, said the policy change was made after a horse experienced a sudden death at Gulfstream Park after receiving a so-called “iron shot.”
“The iron shots, apparently, if you give them too fast or if you give them just a plain iron shot, unfortunately, it can drop them to where it kills them,” he said.
Badgett said the track had seen a small handful of sudden deaths related to injectable iron supplementation in recent years, and the most recent case was the final straw.
“I think it was a good call; I don’t think the horses really need it, anyway,” said Badgett, himself a former trainer. “I didn’t even know people were still using it, to be honest with you.”
The practice of giving so-called iron shots, which contain iron dextran, to horses is a practice that goes back through the decades. Dr. Mary Scollay, former executive director of the Racing Medication and Testing Consortium and current chief of science for the Horseracing Integrity and Welfare Unit, said the practice probably evolved from concerns about boosting a horse’s red blood cell count.
A lower-than-average number of red blood cells is known as anemia, which can result in weakness, fatigue, and heart palpitations in human. One potential cause of anemia in humans is iron deficiency, most commonly in pregnant women or in people experiencing significant blood loss. One of the treatments for this type of anemia is iron supplementation.
Many trainers have bloodwork done regularly on their Thoroughbreds to monitor for any signs of impending illness, and they pay close attention to the red blood cell count. Scollay thinks that iron supplementation came about because a trainer may see a horse with a count that was in the normal range but not at the top end of that range and figure there were some improvements that could be made.
“That’s sometimes how you get into trouble, with how you get [to the higher end of normal],” said Scollay. “There is a certain argument that says the more red cells you’ve got, to a point, the more oxygen-carrying capacity you’ve got to the tissues and that should increase stamina, decrease the onset of fatigue. In blood doping, that’s why you blood dope.”
The trouble is, most horses (and most healthy humans) probably aren’t anemic or iron deficient without some other strain on the blood supply like pregnancy or internal bleeding nagging at them. Horses who are eating commercially-balanced grain diets are almost certainly getting all the vitamins and minerals they need, including iron. Anemia is rare in horses, and especially rare in active, young athletic horses like Thoroughbreds. When it does occur, it’s usually a side effect of some other illness that would have already reduced a horse’s ability to perform regular exercise.
Read our previous reporting on anemia in horses here.
Scollay said she’s not aware of any studies that have looked at whether iron supplementation in horses has any actual effect on their red blood cell counts, but it’s only likely to aid those numbers if the horse is iron deficient in the first place.
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Iron dextran injectable solution is sold by a variety of reputable and less-reputable outlets on the internet, and it has an appropriate place in veterinary medicine. It’s often used on piglets early in life to combat neonatal iron deficiency anemia, which is one of the more common deficiency disorders in that species. Of course, if a horseman is getting iron dextran from a questionable outlet, they’re running the risk of the product being contaminated. But there are other risks, too.
Iron dextran in horses has been associated with sudden death for decades, and it’s still not quite clear why.
“I’m aware over the years of plenty of horses who either fell off the needle or had an anaphylactic reaction and died shortly after having been injected with iron dextran,” said Scollay. “You send a case off for necropsy and the pathologists are usually able to say that what they found in the examination is consistent with an anaphylactic reaction, but it doesn’t tell you what specifically the horse had the reaction to.”
Scollay said she suspects these reactions are more likely to other ingredients in the iron dextran solution rather than the iron itself, since iron is a mineral found in food, but it’s hard to say.
In 1986, Drs. Thomas Tobin and Steven Kamerling published an article in Equine Sports Medicine News on iron and its metabolism in the horse. The authors were unequivocal.
“Iron dextran injections should not be used to supplement iron,” they wrote.
They cited several case studies of equine death soon after iron injections, in both adult and newborn horses and acknowledged it’s not clear what caused those sudden deaths. They also voiced concerns that iron may negatively impact the horse’s immune system.
Scollay said studies have found a 0.61% risk of anaphylaxis in humans receiving iron dextran. It’s impossible to know whether the rate is the same in horses, but for context, Scollay points out that from current Equine Injury Database figures, the risk of catastrophic breakdown in horses is 0.14%.
“It’s more of an old-time treatment that has largely gone out of style but obviously not completely gone out of style,” she said. “To me, the risk is not justifiable.”
If a trainer wants to supplement a horse with iron anyway, there are plenty of oral products that offer this benefit. Oral iron supplementation has not been associated with the same risk of anaphylaxis in horses as intramuscular injections, according to Scollay.
In her role with HIWU, Scollay said that iron dextran is not on the current list of prohibited substances. There are limits on the use of any injected treatment in relation to post time. It is possible the issue could be taken up in a mortality review, however, if a horse was found to have died with signs of anaphylaxis immediately after receiving an iron dextran injection.
“If we’ve got publications saying you shouldn’t do it, and somebody gave it, they’d better have a pretty good justification for risking that horse’s health,” she said.