With just over 24 hours until the start of the John Beargrease Sled Dog Marathon, teams of veterinarians and veterinary technicians checked the paws, heartbeats, lungs and gums of every dog that might race.

Standing in the parking lot of Lake Superior College on Saturday morning, as his crews of vets traveled from sled dog team to sled dog team, Beargrease head vet Gregg Phillips explained it was about ensuring every dog is healthy when they leave the starting line at Billy's bar on Sunday and establishing a baseline of health information that vets can refer to at several mandatory vet checkpoints throughout the race.

"We kind of look at the dog from the top of the nose to the tip of the tail," Phillips said.

The 36th Beargrease begins Sunday at 11 a.m., with events starting at 9 a.m. at Billy's bar on the north edge of Duluth at 3502 W. Tischer Road.

Once a dog is cleared to race, students from the University of Minnesota's doctor of veterinary medicine program marked the dogs with stripe of orange, green or purple grease to show they've been cleared to compete in its respective race.

Peter Breimhurst, one of the students helping the vets record their exams, said it's been a good learning experience.

"The sled dogs have their own niche-specific body conditions for a sled dog, which is a little bit different than what you're looking for in maybe a pet dog," Breimhurst said. "Tracking their heart rates is one of the biggest things that define how well a dog is doing ... if it's not slowing down after each check in, you can suspect infection, or injury, or dehydration."

Volunteering as a U of M student is how Elizabeth Schnabel, now a in vet Milwaukee, first experienced the Beargrease. She's been volunteering at sled dog races ever since.

She said there are vets at the mandatory vet checks along the course and every single checkpoint in case a problem arises.

"When the first teams start getting into the checkpoint, there's always a vet there, and we don't leave until the last dog leaves," Schnabel said. "Sometimes that'll mean being up all night with them, and we sleep whenever we can here and there. We're always available if anything comes up."

Phillips said only about 6 dogs dropped out of last year's race for dehydration, and all were pulled out by their mushers.

"The mushers know their team better than we'll ever know them, and we can help them make the decision," Phillips said.

He expects there could be a few more that will need to drop out as warmer weather this week could lead to exhaustion and dehydration.

Warmer weather could cause challenges

This week's forecast looks good for Beargrease spectators and volunteers along the course with high temperatures along the north shore forecasted in the high 20s and low 30s while overnight lows will be in the mid teens, according to the National Weather Service.

But mushers and vets both said the dogs would prefer temperatures in the 10-20 below zero range.

Sam Louters, of Hollandale, will be racing the mid-distance race as a junior. He said his dogs will be kept hydrated with plenty of water and a sports-drink like mix formulated for dogs.

"We'll just keep them hydrated and see how well they do, see how the trail is," Louters said. "Hopefully it will cool down good at night."

As for cooling down, the dogs usually roll around in the snow at each stop, he said.

This week's warmer temperatures can also affect the trails.

The trails will likely be softer this year than last year's Beargrease, when temperatures were regularly below 0 in some of the coldest few days in Minnesota history.

When it's cold, the trails are firm and fast, but when it warms up, a dog's paw can puncture the snow with each step.

Kelsey Beber is worried about the potential for her dogs to punch their paws through "mushy" snow.

"This year is going to be warm so the trail is going to be punchy, which can lead to hurt ankles and shoulders," Beber said.

Phillips said that last year's trail was hard so dogs were facing more injuries from the repetitive pounding on a hard surface, whereas punching through a soft surface will result in a more shoulder issues.

But Tony Mai of Big Falls said the weather should be OK.

"I'm not too worried about it," Mai said. "It is what it is ... I'm going to have fun though. That's what my main goal is."