The checker records the time and checks on the mandatory equipment that each musher has to carry. The veterinarian asks about the dogs, asks about any concerns and will examine in detail every dog on the team. There will be veterinarians at many of the unofficial stops as well. Dogs can take vitamins during the race as long as there are no injections. Vitamins can be added to the food and water and many mushers will do this, as well as take vitamins themselves.
Most healthy dogs can run for extremely long periods of time.
They have been training for months to years and are like marathon runners. The exact time will depend on the team, the weather and temperature, hills and of course, the team strategy. All dogs are subject to drug testing at all times. Random urine samples are collected during the race, and five or more times from each of the top five teams will be collected at the finish. The testing is done by a laboratory that does race tracks all over Canada and the U.S. and test for almost anything you can think of.