The 51st Iditarod kicks off Saturday with a ceremonial start in Anchorage, Alaska, and the official restart happening at 2 p.m. in Willow, Alaska. The 1,000-mile Last Great Race on Earth tests the limits for the mushers and the dogs as they traverse the frozen landscape of the Last Frontier.

Before the trek begins, the racers are gearing up their sleds and spending time with their fans.

Of course, the Iditarod can’t happen without the dogs. These four-legged stars have a series of events of their own before race day. High on that list: mandatory vet checks.

According to Dr. Stu Nelson, the Iditarod’s chief veterinarian, vets will take blood samples from all of the dogs to get a look at their “overall body condition.” Those blood tests will be followed by ECGs and EKGs to check for any heart abnormalities.

Critics of the race view the race as abusive. PETA has accused mushers of abuse for years.

The group’s executive vice president, Tracy Neiman, said she believes that “as PETA alerts more people to the number of dogs who have died along this thousand-mile trail, the Iditarod will soon have no choice but to call its final race.”

Mushers, naturally, disagree and say they have a special bond with their Iditarod dogs.

“I think people just need to trust that this event is not put on by a bunch of animal abusers. That’s not what you’re seeing here,” Iditarod musher KattiJo Deeter told Straight Arrow News. “What you’re seeing is a bunch of people that love dogs and love spending time with them and being out in the wilderness. And you’re really seeing this awesome relationship of human and animal that we honestly don’t have a lot of anymore.”

The animal rights organization backs up its prediction by noting that the Iditarod has fewer sponsorships this year and low participation.

It’s true that the number of racers is down this year, with 33 mushers compared to least year’s 50. But participants don’t appear worried.

“33 mushers is a low end, but it’ll come back; it’ll bounce back,” musher Matthew Sailor said in interview with Straight Arrow News. “We may not see 80 or 90 mushers like we used to, but dog mushing isn’t going to go anywhere, it’s just some people retire … and maybe it’s just a low rookie class and lots of the mushers are having kids now and lots of their priorities are changing. But dog mushing will be strong no matter what.”

Stick with Straight Arrow News for more footage and interviews from the Last Great Race on Earth.