The Iditarod sled dog race in Alaska has had a messy start, with a five-time champion shooting and killing a moose to protect himself and his dogs, race officials said on Monday.

Under race rules, the musher, Dallas Seavey, had to stop to gut the moose before continuing the 1,000-mile race.

Seavey killed the moose after it became “entangled” with the racer and his dogs during the race, the Iditarod said in a news release. Iditarod Trail Sled Dog Race officials were notified at 1:43 a.m. on Monday.

One of Seavey’s dogs was injured in the encounter and flown to Anchorage to be evaluated by veterinarians, the Iditarod said. The dog, Faloo, was in critical condition on Tuesday after undergoing surgery, according to Seavey’s Facebook page.

The race marshal, Warren Palfrey, said in a statement that he would continue to gather information about the moose killing and make the most of the death. “We are making sure that every attempt is made to utilize and salvage the moose meat,” Palfrey said.

The Iditarod’s Rule 34 addresses the potential killing of “edible big game animals,” including caribou and buffalo, in the course of the race.