By Sally Simon, Finalist for Target® 2011 Iditarod Teacher on the Trail™, New York
The Alaskan sled dog is widely known as being the most athletic dog in the world. These marathon runners are revered for their strength and endurance. However, just like human athletes, they’re not problem free. Some of their issues arise from characteristics inherent to their breed; others arise from their athletic training similar to humans.
While it’s commonly known that the Iditarod dogs go through a regimen of tests and physicals both before and during the race, lesser known is that there’s ongoing research on sled dogs at major universities. For the past twenty years research has been conducted in six major areas concerning sled dogs: enlarged heart, gastric ulcers, muscle metabolism, vaccine titers, red blood cell count, and most recently diarrhea.
It’s a fact that sled dogs have enlarged hearts. It is a genetic trait. The question is, “Is that a problem?” Studies conducted in the 1990s sought to answer that question. ECGs were conducted on dogs and it was found that 50% of sled dogs have heart murmurs naturally, running or not. Heart murmurs may be a problem for other breeds, but it’s not for sled dogs—well, not if the murmur is on the left side. If the murmur is on the right side, however, it’s cause for concern. A dog with this condition will be disallowed to run the race.
The second area of research on sled dogs concentrated on gastric ulcers, a condition also common to human marathon athletes. Approximately 50% of sled dogs experience gastric ulcers; although they’re usually not a threat to their health unless internal bleeding occurs. Additionally, the research showed that no link between gastric ulcers and diarrhea exists. As a result of this research, the Iditarod has recommended mushers give their dogs Pepcid, an antihistamine that blocks the release of stomach acid, in order to prevent gastric ulcers. It’s believed that most mushers follow this advice for the best care of their team.
Another major study of sled dogs started in the early 2000s and is still ongoing. You may be surprise to find out that it was financed by the U.S. government. This 1.4 million dollar endeavor focused on muscle metabolism. The aim was to study how the sled dog can run for such long distances day after day and have metabolic recovery. The ultimate goal was to relate the endurance of dogs to humans, in this case soldiers. Michael Davis from Oklahoma State University’s Center for Veterinary Health Sciences says, “The secret to the dogs’ feats of day-to-day endurance lies in their ability to ‘reprogram’ their bodies’ responses to stress after just one day of competition. Something humans can’t do.” When an athlete, be it human or canine, pounds the pavement for miles, bits of muscle enzymes and proteins leak out of their cells. This is a sign of cell damage. For humans, the cells recover in a day or two. However, as soon as a human goes for another run, the damage happens all over again. For sled dogs, that’s not the case. They adapt their systems within a day, and the leakage doesn’t occur.
Davis also found that sled dogs have voracious appetites. During race season, a sled dog that weighs 55 pounds can consume up to 12,000 calories a day. Human athletes can do the same, but their body weight is three times more than a sled dog. Sled dogs diets need to be very high in fat and protein. It’s comparable to a human marathoner training by “eating the Atkins’ diet,” says Erica McKenzie, researcher at Oregon State University who once worked under Davis. As a runner herself, she also wishes that there’d be more transfer of the dog research they’re conducting to the human world of sports medicine. But, “we just aren’t there yet.”
In 2006 & 2007 two studies were conducted at Oregon State University. The first concentrated on vaccine titers. The question explored was, “Does the stress on a sled dog affect the effectiveness of their vaccines?” The study showed that some dogs did experience a weakening of vaccines. However, the study also revealed that when these same dogs were exposed to various diseases during race, their immune system built up a tolerance 4x that of the vaccine. The second study focused on red blood cell count. It was discovered that for every day of a race, the red blood cell count dropped by 1% in 40-45% of the dogs tested. This phenomenon also happens in human athletes in races such as the Tour de France. After the race, however, the red blood cell count returns to normal levels. The conclusion reached is that the lowering of the red blood cell count is a natural response to exercise for both humans and dogs, and it has no harmful effects.
The most recent research conducted on sled dogs is in the area of diarrhea, which is a widespread and poorly understood problem. Erica McKenzie has been a leader in this area of research for the last few years. She took samples of dogs before the race and after 400 miles of running and conducted testing. Although there’s still research to be done in this area, her studies showed that the diarrhea was not a result of disease, rather a natural response to the stress of running. Again, this same issue is not foreign to human athletes. She said that in most cases, the diarrhea is more of an annoyance than a health issue. Dogs usually regain normal regularity within a day or two. There’s one exception though. If the diarrhea is 9% watery, then it’s a sign of a health issue. If the watery condition continues for more than a day, a dog will probably be dropped.
This research is hot off the presses and was shared this year with the mushers at their meeting the Thursday before the Iditarod start. The practice of veterinary research being shared with mushers is a long standing practice. Mushers are receptive to finding out about health issues concerning their dogs. I’ve seen first-hand how the care for their dog team is the ultimate priority of a musher. Now I know it’s also a priority with several researchers around the country. It’s been said the sled dog is the most cared for athlete in the world. I think it’s safe to say they’re also the most researched athlete in the world, at least the ones with fur. Hopefully the research being done on sled dogs will be transferred more consistently to humans marathoners and help them as well.
(Special thanks to Erica McKenzie of Oregon State University for graciously giving of her time for an interview so I could learn about this fascinating subject).
For More Information:
Why Sled Dogs are Super Dogs: http://www.msnbc.msn.com/id/26889282/
Iditarod Dog Car Measures: http://www.iditarod.com/learn/vet-10.html
Sled Dogs and Enlarged Hearts:
*http://www.gi.alaska.edu/ScienceForum/ASF12/1223.html
Sled Dog Endurance:
*http://www.nytimes.com/2008/05/06/science/06dogs.html
*http://www.scienceline.org/2008/11/28/bio-teyan-sled-dog-metabolism-iditarod/
*http://www.faculty.uaf.edu/ffmew1/krista_west/magazine/SledDog_KristaWest_1p.pdf
*http://www.newser.com/story/26658/what-we-can-learn-from-being-dog-tired.html
Sled Dogs Diet:
*http://jn.nutrition.org/cgi/content/full/128/12/2686S
Sled Dogs and Insulin/Diabetes Research:
* http://newsok.com/dogs-could-help-diabetes-studies/article/3335362?custom_click=lead_story_title
*http://spkenneldoglog.blogspot.com/2009/11/physiology-research-at-sp-kennel.html
Sled Dogs and Diarrhea:
*http://www3.interscience.wiley.com/journal/122686405/abstract
NOTE: For high school students conducting scientific research, or who are involved with the INTEL science program, sharing this area of research might spark an interest in a related topic.
