A record 75 mushers and more than 1,400 dogs began their trek Saturday from downtown Anchorage to Nome under sunny skies in the 19th Iditarod Trail Sled Dog Race.

Temperatures were in the teens and 20s, cooler than the 40-degree-plus temperatures during the week that had participants worrying about their dogs' discomfort and soggy trail conditions along the 1,163-mile route across Alaska.Four-time champion Rick Swenson was unconcerned as he surveyed his dogs before the race.

"The trail doesn't matter much to the dogs. Warm weather is more conducive to the type of race I want to run, to fast races," Swenson said.

Swenson is trying to win a record fifth Iditarod victory before defending champion Susan Butcher does.

Waving to fans, talking to sponsors, giving orders to her crew and nuzzling with her dogs, Butcher said she'll adjust to changing weather "but the main strategy is always to take the best care of that dog team. To give them plenty of rest."

The race began at 9:02 a.m. (11:02 p.m. MST) when Brian O'Donoghue, a newspaper reporter and rookie musher from Fairbanks, sent his dogs sprinting down down Fourth Street. The former wire service photographer and New York City cab driver won his starting spot by lottery, and wore bib No. 2.

The other mushers and their teams followed at two-minute intervals. Bib No. 1 is an honorary bib.

Thousands of fans lined the streets and the howling and barking of waiting dogs could be heard for blocks.

The race, which commemorates the historic 1925 relay of diphtheria serum to ailing gold miners in Nome, follows the southern route this year, winding across tundra, mountain passes, frozen rivers and Bering Sea coast.

Last year, Iditarod mushers faced record snows, corrosive ash from Redoubt Volcano and starving moose on the trail.

This year, the wet trail created by record warm temperatures in Anchorage and Nome will turn icy as temperatures cool. Most of the dogs wore booties as they headed out of Anchorage.

"In weather like this we'll just have to take it easy," said musher Beverly Masek, who will go through her hometown of Anvik during the race. "There'll be a lot of booting up."

Masek tied yellow ribbons to each of her dogs to honor her main handler, Kurt Birkholz, who missed the race because he was called to active duty in the reserves.

While veterans like Swenson and Butcher aimed for the $50,000 first-place purse, many mushers, particularly the 29 rookies, would be happy just to finish.