Please cite a reference that is not PETA or ASPCA that shows these canine athletes are in pain at the end of a race.
I don’t need a reference, nor would I cite anything from anti-pet and anti-meat orgs.
What I do have is 40 years plus of dog ownership. I’ve owned many types of dogs, including various working and hunting dogs. Thirty plus dogs at this point and currently own 7. I’ve dealt with dogs that were in pain from working hard for a day, much less than the herculean effort required for the Iditarod. Many dogs drop out of the race by being withdrawn by their musher or race vets.
I know how tough dogs are. I well know how much they can take. They will work or run for their people far past injury, which is why folks need to be very cognizant of their animals when working them.