Early on the morning of May 26, Kristen Williams and her daughter, Katie, arrived at a barn on the grounds of the Devon Horse Show, where elite competitors in full dress have entertained spectators for the last century on Philadelphia’s Main Line.

Williams had paid thousands of dollars to lease a pony for Katie to ride in a hunter competition, a 12th birthday present. Soon after arriving, their trainer left to administer an injection to a nearby pony, Humble, that Katie’s friend, also celebrating her 12th birthday, was scheduled to ride shortly.

Moments later, with Williams and her daughter watching, Humble collapsed and died. The death of a supposedly fit pony about to carry a young rider over hurdles was worrisome by itself, but circumstances surrounding the death made it even more so.

In the three days before Humble died, he had been scheduled to receive 15 separate drug treatments, including anti-inflammatories, corticosteroids and muscle relaxants, according to his medication chart.

“The average horse that walks in my clinic here doesn’t get anything like that,” said Dr. Kent Allen, chairman of both the veterinary and the drugs and medications committees of the U.S. Equestrian Federation, the sport’s nonprofit governing body. “It gets a diagnosis and then gets a very specific, appropriate treatment.”

Since 2010, random drug tests at various equestrian events, including the Olympic trials, have uncovered dozens of violations for substances like cocaine, antipsychotics, tranquilizers and pain medication.

While show-horse trainers have abused some of the same drugs that have caused problems in racing, the Equestrian Federation has lagged in regulating how they are administered.

The group says it responds promptly to drug concerns, citing its decision in February to ban a popular but potentially lethal drug that sedates horses, making them more manageable during competition. The group has also limited the use of anti-inflammatory drugs in competition. It randomly tests 10,000 to 12,000 horses annually. “We constantly look at issues in our sport and try to be proactive,” Allen said.

Still, a review by The New York Times of federation records, police reports and interviews with veterinarians and others in the sport shows that despite its best intentions, the federation is ill prepared to deal with episodes like Humble’s death.

At racetracks, only veterinarians are allowed to administer intravenous drugs, but on show grounds anyone can stick a needle into a horse before it performs.

The federation also has no detailed protocol on how to respond when a horse dies on show grounds. In Humble’s case, there was no requirement that the vial and syringe be retained so its contents could be tested. And the federation relied on the mother of a competitor who saw Humble fall to collect evidence, hire a lawyer, and file a formal protest.

The federation, often referred to by the acronym USEF, convened a hearing panel, but it had no subpoena power and could not compel Humble’s trainer, Elizabeth Mandarino, to fully answer questions about the pony’s medical care, records show. The panel ultimately dismissed the protest, saying it did not have enough information to conclude whether Mandarino had violated federation rules.

Mandarino declined to be interviewed. Her lawyer said in a statement that she had done nothing wrong, and that Humble had most likely died from an undiagnosed lung disease.

Much of the concern about drugs centers on hunter competitions, where young riders and future Olympians develop their skills.

“This is only a ticking time bomb,” said Julie Winkel, who runs a stable and has judged major shows nationally. “It’s not only the wrong thing to do for the horses, but I think it’s a very dangerous situation that we have created for the rider, handler, even grooms.”

Calming the horses

More than blue ribbons and prestige are at stake in equestrian competitions. Horses that win big events increase in value, rising into the hundreds of thousands of dollars.

Hunters are judged subjectively, with an emphasis on well-mannered horses that jump safely and smoothly over fences. Temperamental horses with unnecessary movement or exuberance show poorly. Time is not an issue.

For these reasons, calming drugs and supplements are popular on the hunter circuit, even though drugs that influence a horse’s behavior are banned in competition.

Calming drugs allow horse owners to lease their animals to less skilled riders willing to pay thousands of dollars to compete. Besides creating an uneven playing field, some calming drugs can endanger horse and rider, and be difficult to detect in post-competition testing.

A prime example: an injectable calming supplement called Carolina Gold. The federation first heard of it from competitors early in summer 2011, according to Dr. Stephen Schumacher, the federation’s chief veterinarian.

“The reason people were talking about it was because they were tired of getting beat by people using this substance,” he said. “We were also hearing reports of horses falling down.”

To see how Carolina Gold affected horses, federation officials injected one with the substance. “The horse nearly collapsed,” Schumacher said. “It starts shaking and was really out of it.” The reaction was so worrisome that the attending veterinarian refused to test it on any more horses.

The federation now knew the drug was dangerous, but there was a problem: it was undetectable in horses.

Dr. Alex Emerson, a Kentucky veterinarian who blogs about horses, wrote this year that he had long worried about Carolina Gold’s “narcoleptic” effect. “How can half-asleep horses jumping 3-foot wooden fences with a live human on their back be considered safe?”

Heavy medication

A week before Devon, Kristen Williams took Katie, her daughter, to a Florida show to try out Royal T, the pony she planned to ride. Katie’s friend Katie Ray had also traveled to Florida to try out her pony, Humble. Both ponies were owned and trained by Mandarino.

Afterward, Williams said she was surprised that Mandarino’s invoice listed $435 for unidentified “supplements.” Katie Ray’s mother, Carrie, had been billed $250 for unidentified supplements, records show.

At Devon, the following week, Williams came across the list of 15 scheduled drug administrations. All the drugs were legal. Saying she was shocked to see the horse so heavily medicated, Williams snapped a picture of the list with her cellphone. The following day, Humble collapsed and died after receiving another injection, this one not listed on the chart.

When told of the list of drugs, Dr. Rick Arthur, chief veterinarian for the California Horse Racing Board, said, “The treatment seems intensive even by racetrack standards, but I am unfamiliar with show-horse practices.”

Allen, who has extensive show-horse experience, said most vets he knew could not imagine using all these drugs, “particularly large amounts of them in multiple combinations.”

“Does it bother me that somebody injected a horse that close to competition? Yes, it does bother me,” said the federation’s Schumacher. “We’ve got to find a way to enforce whatever we want to put in place to curb that behavior.”

The burden for investigating Humble’s death fell largely to Williams who described herself as a relatively inexperienced “pony mom.”

“What if Humble had made it to the ring and collapsed with Katie on his back?” Williams stated in her protest filing in June. “I am extremely concerned for the welfare of the animals and the innocent children that could potentially be victims.”

A post-mortem exam of Humble found an anti-inflammatory and a muscle relaxant, though not in excessive amounts, and no illegal drugs. In addition to emerging lung disease, the exam concluded that the pony could have died from “an overwhelming allergic response to medications or environmental triggers,” but said that was “speculative and impossible to confirm.”

In the end, the federation hearing panel dismissed Williams’ protest, saying it did not have enough evidence to decide if rules had been broken.

Mandarino filed an unsuccessful complaint against the federation’s general counsel with the Kentucky Bar Association and has filed a lawsuit accusing an online publication, Rate My Horse PRO, and various individuals of conspiring to harm her business. Rate My Horse PRO, which says it is an advocate for horses, has filed papers seeking to have that lawsuit dismissed.

A growing number of people in the horse world see another way of thinking about a horse’s behavior in the show ring. This year, Winkel’s committee called for judges to stop rewarding horses for robotic conformity.

“People are realizing that it’s OK if horses are a little fresh and a little happy,” Winkel said. “Why don’t we take a little more time and train these horses properly and educate their clients and give them better horsemen skills, other than to bring out a needle and a syringe every time we have a horse show.”