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How Iditarod dogs outrun Grim Reaper

Jill Burke

The deaths of six dogs during the 2009 Iditarod Trail Sled Dog Race cast a pall over the annual 1,000-mile race across the wilds of Alaska -- a grueling event that tests and celebrates survival. It wasn't unusual that dogs had died. One or two deaths -- sometimes more -- in any given year were predictable. And the deaths that did occur represented a minute fraction of the canine racers, considering that up to 1,000 dogs a year run.

Under any circumstances, the loss of a race dog is heartbreaking. But the truth is they sometimes die. Ultra-fit marathon endurance dogs, like any other extreme athlete, can drop dead without warning. And regardless of how fit a dog may be, the race can pose other lethal obstacles: extreme weather, poor trail conditions, crashes, wild animals.

The stars aligned in 2010 and 2011, delivering great weather, decent trails, and no run-ins with moose. Years of medical research on sled dogs was also starting to pay off, leading veterinarians and mushers toward a potent change in their regimen: heartburn medicine. Just like NFL superstar quarterback Brett Favre, race dogs are popping a small but powerful pill to keep their intestines as finely tuned as the rest of their bodies. It's thought the change has and will continue to save lives.

But years of breeding, improvements in gear and changes in food can only do so much. Two dogs died in the 2011 Yukon Quest International Sled Dog Race, another remote, 1,000-mile race that travels between Fairbanks and Whitehorse in the Yukon Territory. Geronimo, a dog on Tok musher Hugh Neff's team, died from aspiration, and a dog named Taco in Fairbanks racer Brent Sass's team died from something the race's executive director called "runner's syndrome" -- a casual reference to a medical condition in extreme athletes known as "athletic heart syndrome."

"We try to learn from every sad circumstance," said Quest head veterinarian Kathleen McGill from her home in Ohio after this year's race. "Because we know so much more, we are more proactive than reactive," she said.

Twenty years of working dog races has allowed McGill to witness the evolution of dogs and dog care. She's happy to report that the 2012 Quest was "boring" -- no close calls with dogs, no dramatic rescues, no wild weather. But while McGill can comfortably look back at this year's race, the chief veterinarian for the Iditarod isn't resting as easy.

"This year I am concerned about moose," chief veterinarian Stu Nelson said from Iditarod Trail Headquarters in Wasilla one afternoon as he performed dog checks. The heavy snowfall Alaska has received this season has already resulted in run-ins with moose by drivers and trail users. Chances are good they'll show up somewhere along the Iditarod trail.

Nelson and his team of veterinarians hope 2012 will bring a dog care three-peat. "We would all love to have no deaths out there, and we will do everything we can to prevent it," he said.

But, he cautioned, "We don't have the power over life."

Ulcers and antacids

In 2007, a lead dog named Snickers started the Iditarod, but never finished. About two-thirds into the race, Snickers died unexpectedly. A blood transfusion and emergency care by four veterinarians couldn't save the dog from what was later identified as a bleeding ulcer, according to Snickers' owner, musher Karen Ramstead.

Snickers met the same fate that researchers say has historically been a leading killer of race dogs. Studies by Dr. Michael Davis from Oklahoma State University have shown that exercise-induced stomach disease may affect 50 to 70 percent of the dogs that enter the race, a number far higher than is seen in non-racing dogs. Those that develop the condition are at risk to develop ulcers, a more serious progression of the illness.

Quietly and with no outward signs, ulcers wreak havoc with a dog running intensely. Chronic slow bleeding, an acute onset of major bleeding, and vomiting that leads to choking all can be fatal side effects of this otherwise silent condition. Davis made the discovery about the prevalence of ulcers in racing dogs after 10 years of performing exams on dogs as they finished the Iditarod and other races.

Since there was no way to easily detect the presence of an ulcer, hindering treatment during the race, preventing the condition was key. Before long, a gastric acid suppressant -- sold under the brand name Prilosec -- was added to the dogs' daily race routines. But it wasn't until around 2009 that researchers found giving the medicine on an empty stomach was even better. Nelson calls that discovery the "most dramatic" of the medical research on racing dogs in recent years -- and one that had instant results.

"We have gone to showing we can not just have zero death races, but we can do it . . . more than once," he said.

The ulcers may develop as the dogs' bodies adapt to the stress of a competitive pace. "These are highly athletic animals and they get all pumped up for the race, just like humans do," explained McGill, the Quest chief vet.

Davis has theorized that “in the process of attaining fitness, circumstances will allow the acid in the  stomach to periodically pass through the lining of the stomach and injure the tissue underneath, resulting in inflammation.” Given enough days of rest, this condition can heal. But endurance racers don't get the chance to do this, as it can take more than a week to recover. Race dogs run or lope day after day after day and, according to Davis, end up competing with a “persistent, low-level inflammation of the stomach.”

Other theories suspect the origin of gastric conditions might be dietary, mechanical or related to the physiological aspects of running. Whatever the reason, Nelson and McGill have both credited Davis' work and the incorporation of Prilosec with preventing deaths. “It makes a big difference,” Nelson said.

It's what to eat

Incredible athletes, sled dogs are more efficient, more conditioned than just about any other animal on the planet. They have been shown to have the highest metabolic rate of any mammal, according to Nelson, who points out that the next most efficient calorie burner is a lactating mouse.

The mystery metabolism of sled dogs has even drawn the attention of the Pentagon. Interested in building better soldiers, it has given money to Davis’ research in hopes of finding ways to improve human performance. And still other studies are underway to find out if the incredible ability of race dogs to burn fat can help humans conquer obesity or type II diabetes.

We now know that sometime early in a race, sled dogs undergo a big shift in metabolism. Instead of burning carbohydrates, as human runners do, they begin to burn fat. Mushers adapted by making sure their dogs get the calories they need to run and run and run. Where before dogs might have been taking in 4,000 calories a day, now they're fed fat-rich diets of 10,000 to 12,000 calories daily. That's the equivalent of about 20 McDonald's Big Macs per dog, and to get the same energy a heavier human runner would need to eat more than 50 of the fat-laden burgers.

When Nelson first started working races as a trail veterinarian, dog diets were heavy with fish and meat, supplemented with kibble. Nowadays they are heavy with nutrient-perfected kibble and fat, supplemented with fish and meat. Given the unique metabolism of the dogs, it makes sense. Fat is the most calorie-dense food, followed by carbohydrates and then protein.

Sled dog myopathy

For all of the advances in dog care, a condition called sled dog myopathy still lurks and can be fatal if not caught early.

Known to horse racers as “Monday morning” disease, it surfaces after an animal has had a period of rest before resuming its activity. The name comes from the days when farmers would notice their draft horses, rested on Sundays, would suddenly become ill on Monday when put back to work. They were stiff and sweaty, and some would collapse, generally within the first hour of physical activity.

It's noticeable in sled dogs by their gait, “funny” or “wobbly” running, as some mushers have described it. Muscles and joints may be stiff and sore. But just pulling a dog off the race line isn't enough to save them.

“As sure as the sun comes up, that will kill a dog,” said McGill, referring to an advanced stage of the condition accompanied by dark urine, a sign that the kidneys are processing byproducts of muscle breakdown.

Myopathy is thought to be a metabolic disorder, related to the “switch” the dogs make in what kind of calories they burn to get their energy. Once in fat-burning mode, the glycogen contained in the muscles can stockpile, producing lactic acid which in turn can cause the muscles to break down. It's a nasty cycle. As the dog gets sicker, kidney failure may follow.

It shows generally shows up in the first 300 miles of the race, not surprising as dogs shift into fat burning mode around this same time, after three-to-four days of competition.

Mushers and vets are trained to watch for signs of myopathy and take early action, administering IV fluids.

Four-time Iditarod champion Lance Mackey fretted about this very illness when forced to drop four of his dogs during the 2011 race –Maple, a lead dog, and Lippy, Pimp and Jester. For reasons unknown, the quartet was obviously struggling -- “crab walking,” in Mackey's words – less than 300 miles into the race near Rohn and Nikolai. Although his dogs weren't seriously ill, Mackey feared his dogs were suffering from myopathy, and he made the difficult decision to continue without them, dropping Maple in Rohn and the other three at the next checkpoint. 

Athletic heart syndrome 

 Racing sled dogs are required to get a battery of blood tests and undergo heart monitoring before the race. Electrocardiograms have helped race officials find and pull out otherwise healthy looking dogs discovered to have some underlying heart condition.

Among endurance athletes, the condition is known as athletic heart syndrome, a normal, physiological response of the body adapting to the needs of rigorous exercise. The heart enlarges to enable the body to keep up with the oxygen demands of sustained exertion.

Most athletes, including dogs, won’t have trouble with this condition. But if the heart gets out of rhythm, or has some other abnormality, dogs and humans alike can die suddenly. Through the use of pre-race ECG's, trail veterinarians have “pretty much selected out those dogs that may have that problem,” McGill said. Dogs that don't pass the ECG don't run.

“There can be underlying abnormalities that can make them predisposed to going into an arrhythmia -- and collapse and die,” said Nelson, McGill's counterpart in the Iditarod.

Nelson is careful to point out that athletic hearts aren't a pathological condition. But other heart problems, caused by infection, neurological issues or other abnormalities, can be.

Evolution of elite racers

So much has changed over the years in long-distance races that it's difficult to pinpoint one “magic formula” that has led to better dog health and performance. If one had to be chosen, it would likely be attentiveness. Breeding, feeding, training, race equipment and medical advancements all play a role.

Some issues, like frostbitten feet, seem to have been eliminated with breeding, said McGill of the Quest. Dogs with feet better able to withstand the rigors and extreme cold of the race require less care, and the introduction of hound dogs into the blood lines have created smaller, faster runners.

Racing has evolved to a point where most dogs are full-time athletes, trained specifically for competition instead of other duties throughout the year like hauling wood, bringing in the mail or working trap lines. In fact, only one musher in this year's Yukon Quest race, a man from Russia, brought working dogs – used to hunt and fish – to the start line, said the event's executive director, Marty Steury. He finished last.

Mushers have also become mini vet-techs in their own right. Educated about dog care, in tune with their teams, they know their dogs best and have adapted their protocols as new research comes out. With this vigilance, it's likely problems are detected quickly and dealt with before small problems become big problems. Rookie mushers, still learning the nuances of distance racing and dog care, are closely watched. With veterinarians at every checkpoint, swift care is accessible.

“Every dog is unique. They eat differently. They have different ways of moving. They have different personalities,” Nelson said, who encourages mushers to pay attention to the smallest  of details. Changes in energy, in performance and even poop can be early indicators of problems that need attention.

Still, the six dog deaths during the 2009 Iditarod weren't all performance related. One dog died when the plane it was riding in hit severe turbulence. The dog was knocked into position that caused it to choke on its collar. Two other dogs died from hypothermia, part of a rookie musher's team that was suffering in the brutal, minus-45 F weather. And two of the six dogs died from fluid-filled lungs, a condition likely caused by some heart abnormality, according to race officials.

As the 2012 race approaches, Nelson carries with him the difficult reminder that humans can only do so much to care for the dogs they love.

"Obviously there is no reason on earth that anybody would want a dog to die. It all has to come together," he said.

Contact Jill Burke at jill(at)alaskadispatch.com