Ask the Vet with Dr. Mike Davis 1/19-1/31

Here we'll stuff all those things we want to keep for later reading. Like the "Ask the musher"-series.

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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby runaway_sibe » Mon Jan 24, 2011 9:43 pm

Hi Dr. Mike.

Thanks a lot four time to answer all my questions. Your expertise, and your answers been for so much help to me, and the mushing. And that is, because its so easy critics from a nice and warm office in México, (or Florida), but if one is there, in Alaska, living with 80 dogs, wow, what a difference.
I'm almost finish to read the book "César's way" from César Millán, and he menctioned something very important, at least for me. He cites dr. David L. Mech and his observations about the wolfs, and the fact that no more than 5% of the wolfs' hunting got success. But he mentioned that the wolves keep doing, and it compares in a way to the clasic "go to work" in the humans. They also says that its in the dogs nature, the necesity to walk with a leader.
So, if I see in this way, mushing is almost a thing way deep in the nature of the dogs, an hence, it could be more inhumane, more cruel, to have a dog in a 4 walls bedroom all the time. Right?

Thanks a lot, once again, you help a lot. :D
"A bone to the dog is not charity. Charity is the bone shared with the dog, when you are just as hungry as the dog"
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby eorogers » Mon Jan 24, 2011 11:04 pm

Dr Mike

Thank you for sharing your expertise with us.

Can you give us an idea of what is going on during the rest / recovery period in a long race. Specifically, if in a 24 hour period I am going to run for 16 hours and rest for 8, can you talk about the factors that determine the best way to distribute that rest? I.e. should I run for 8 and rest for 4, run for 16 and rest for 8, run for 4 and rest for 2, go asymmetric and run for 8, rest for 2, run for 8 and rest for 6, or something else?

Thanks

Eric
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby Leaddog » Tue Jan 25, 2011 5:10 am

Hi, Flowerpower
I guess in a way you could say that all athletes that undergo extreme exercise are at risk for vomiting. Depending on the broadcast philosophy and standards, you may get to see more vomiting than you can stand while watching a recap of an Ironman competition. Up to 80% of triathletes have some form of stomach irritation or ulcers, and the irritation is what causes the vomiting. Whether you aspirate in the process depends a bit on your coordination and your head position - it the vomiting is timed between breaths and you get everything clear of the mouth, then you don't aspirate. I don't know what the rate of aspiration is in human athletes so I can't say for certain whether dogs are more or less prone to that part of the process. I am certain, though, that the rate in dogs is low for the simple reason that there is no such thing as a dog aspirating without consequence - 100% are going to get very sick, and we don't see very many of them.
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby Leaddog » Tue Jan 25, 2011 5:13 am

Hi Gabrielle
My opinion is that the dogs value both companionship and exercise. Non-athletic dogs will probably tolerate being kept in a closed room as long as they have company, but athletic dogs need to be athletic, and that takes some room.
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby Leaddog » Tue Jan 25, 2011 5:40 am

Hi Eric. I know you want a simple answer, but I'm afraid I don't have one, and I'm pretty sure you can guess why - not all trails are the same. The key to sled dog racing is sustainable exercise, meaning that you are providing the nutrients as fast as you are burning them, and you are getting rid of waste as quickly as you are producing it. So if you say that the dog's energy reserves are "off-limits", at least from a planning standpoint, then you need to stop and refuel when you've burned the calories you put in the tank since the last stop. The rule of thumb for a reasonably flat, groomed trail is 60 calories/mile, so if you fed 2 meals at the beginning and end of the last break, and the meals totalled roughly 3000 calories, then you've got 50 miles in the tank. From a calorie-burn standpoint, there is actually little difference between a walk, trot, or lope with respect to calories/mile (again, assuming a uniformly flat, groomed trail), provided the dog is capable of selecting whichever gait they chose. They will chose the most energy-efficient one for that speed. The difference is whether internally, they can supply the nutrients and get rid of the heat fast enough. If you assume that all dogs have a uniform-sized stomach that holds 3000 calories (indulge me here for the sake of illustration), a dog that internally can only supply nutrients to support 6 mph will need to stop after 8.5 hrs, but a dog that can supply nutrients to support 12 mph will need to stop after a bit more than 4 hrs - both after having traveled 50 miles. Obviously, the equation starts to shift if it is not a nice, flat groomed trail - if you are going up mountains or breaking trail in soft snow, calories/mile will be higher and you will be stopping sooner.
We've done a bit of study on rest periods, and to a large extent, the rest period is dictated by how far off that ideal "didn't use reserves" the previous run actually was. Early on in a race, before the dogs have really adapted, their rest periods probably need to be a bit longer to fully recharge and restore the balance. However, later in the race when they've adapted, the rest periods probably don't need to be as long - provided the run speeds and intensity have remained the same. If the run speed or difficulty increases, then the rest period may need to increase because even in the face of that wonderful adaptation, you still tapped in to the reserves.To illustrate - we did a study on the Denali Highway (nice smooth groomed trail) running 6 hr on, 6 hr off, with the runs covering 50 miles. During the first 2 days, the dogs weren't completely recovered metabolically from the run at the end of the 6 hr rest. They were good to go, but they weren't quite back to baseline. During the latter 3 days, the 6 hr rest was more than enough to get them back to baseline for the same run.
I think one of the critical "mistakes" mushers make in planning their races is planning per day, and treating the run times and the rest times as somehow needing to fit a specific ratio (whatever that ratio is). That produces the unavoidable temptation of having everything add up to an even 24 hrs. That 24 hrs makes the math more manageable, but it is an arbitrary endpoint that doesn't necessarily fit what the dogs are doing. The goals and demands of the run period and rest period are different and only partially related to each other, so tightly linking them inevitably makes one or the other an imperfect fit.
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby eorogers » Tue Jan 25, 2011 9:50 am

Dr Mike

That actually helps quite a bit - Thanks!

Eric
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby fladogfan » Wed Jan 26, 2011 2:11 pm

Thanks for visiting with us, Dr. Mike. I'm enjoying all the smart questions from the Iditabuds and all the interesting and informative answers from you. My question doesn't concern sled dogs. I have two poms that use to live about 16 hours a day in cages. When they were 8 and 9 years old they joined my family, almost 2 years ago, and now have the run of the house and several walks on leashes daily. They both spin in circles, the girl only when very excited, but the boy will spin any and all times. His leash is always twisted, helps to have one with swivel hooks. Is this an inbred thing or was he caged too much? When he runs towards me his spine seems to be curved and he runs with a twist. Is this spinning a problem with sled dogs?

I've seen dogs at circuses, etc. come out spinning like he does and always wondered how in the world they could be trained to do that. No training neccessary :lol:

thanks, Gretchen/fladogfan
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby Moose » Wed Jan 26, 2011 5:14 pm

Could you offer some information about "ski asthma"? Cause and treatment (hopefully), asks she whose rec team running has been affected by what's been labeled cold-induced asthma?

And I'd love to hear your thoughts on a 20-day Iditarod finish vs. an 8-day finish. Since the race can only be run as fast as the dogs can move a sled up the trail, with better understanding of the benefits of training, conditioning, nutrition and genetics, are we likely to see still further time reductions in future races? Or are the best teams realistically at the peak of their game?
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby Leaddog » Thu Jan 27, 2011 6:05 am

Hi Gretchen. Funny, one of my students had a Pom that did the same thing - obsessively. He didn't always move in circles, but it took quite a bit of determination not to do so when he was moving at all. She named him Pistol, I named him Dizzy. Guess which one stuck.
Poms, and many other purebred toy dogs, have a tendency to be born with or develop a condition known as hydrocephalus. Basically, due to a mismatch between their brain size and skull size, their brain retains fluid and gets squished. Squished brains dont work well, and in these guys, their coordination suffers. Pretty much no cure (even if you improve drainage, they won't grow a new brain), but in many cases, it doesnt seem to bother them a lot.
My guess is it is not due to their confinement entirely - that type of behavior is not uncommon in the breed.
Sled dogs don't really spin in the same way - they will run in circles when excited, but only when they can't run in a straight line (i.e., they are tied to something). Very different.
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Re: Ask the Vet with Dr. Mike Davis 1/19-1/31

Postby Leaddog » Thu Jan 27, 2011 6:31 am

HI Moose.
Strictly speaking, I'm not sure we can say that sled dogs get "ski asthma", although there are some similarities between a sled dog's lungs and the lungs of an athlete with ski asthma. The condition is a combination of lower airway inflammation and mucus secretion that is very common in athletes that exercise in the cold. The inflammation is from irritation to the lining of the airways by the cold air, and the mucus is the strategy employed by the airway to protect themselves from the cold air. The combination of the two results in airways that behave similiar to someone with mild asthma - the passages temporarily constrict following exercise in cold air. By and large, the constriction resolves on its own, and many athletes don't realize they have the problem because they expect to be out of breath after exercise.
In sled dogs, we've demonstrated that exercise in the cold increases the airway inflammation and mucus, and we've documented changes in the mechanical properties of their lungs. All of this is similar to human athletes, but overall much milder in severity. Similar to the human athletes, these changes don't appear to affect the dog's ability to run - the airway constriction happens after the stop running.
There is another condition that is being investigated in sled dogs in which the dog's larynx (throat) will constrict. Although it can be induced by exercise, it appears to be a genetic thing and not something that they acquire. If you can observe the dogs obviously having to work harder to breathe, then I would be suspicious of this disease instead of ski asthma. Either way, not a lot to do - ski asthma doesn't really require treatment, and the larynx constriction isn't something you can cure (although you can manage it by identifying situations that seem to exacerbate it and avoid those).
I think the different in 20 days and 9 days has been a combination of training and learning how to manage the team during the race. This latter aspect is not just how to be efficient, what to feed, and how to manage the run-rest cycles. It is also learning what the dogs are capable of. It wasn't too long ago that folks thought doing the Quest and Iditarod in the same year with the same dogs was impossible. In fact, in 2006 when a bunch of folks decided to do it, the head vet at the Quest (Vern Starks) asked me to do a study checking the dogs over at the end of the Quest and comparing them to the ones at the start of Iditarod. The idea was to (hopefully) show that there was no difference and thus it wasn't inherently dangerous to the dogs to push them that hard. Well, we never published the study because our meager data showing that the dogs were healthy enough to run Iditarod were overshadowed by the realization that they were healthy enough to WIN Iditaod. Point is, I'm not sure we have found the top end to the dogs even yet.
Will we see someone break the 8 day mark on Iditarod? I doubt it, but I think 8.5 days is achievable with the right combination of training, circumstances, and luck. I think it is possible to average 10 mph, and combining that with a 50:50 run:rest ratio as a ballpark, that is 200 hrs or about 8.3 days. But it will not only take top-quality dog conditioning, it will also take the perfect trail and weather and a very fit musher. Actually, it will take at least 2 very fit mushers - there will have to be competition for them to keep the pedal to the floor all the way to Nome.
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