The U.S. Bureau of Land Management suspended a wild horse roundup in northeast Nevada on Monday after seven animals died of dehydration and another was shot when it broke its leg in a holding pen.
Animal rights activists were outraged, saying the outcome was predicable given the sweltering temperatures and helicopters used to gather the animals.
The BLM said the animals appeared in otherwise good shape when two groups were herded by helicopter to holding pens in northern Elko County on Saturday. But the roundup was halted Sunday morning after four horses were found dead in the pens and others showed signs of colic and brain swelling.
In all, seven died of what the BLM called dehydration and complications from "water intoxication" that can occur when dehydrated animals drink excessive amounts of water. The condition causes colic and brain swelling, the BLM said.
BLM Director Bob Abbey said the agency was committed to treating the animals humanely and that the roundup was suspended so "options for minimizing mortality of horses weakened by dehydration can be assessed."
Ginger Kathrens, executive director of The Cloud Foundation, a Colorado-based wild horse advocacy group, called the BLM's actions "disgusting."
The horses "were run over volcanic rock by helicopter for mile after mile," she told The Associated Press. "We're talking about the hottest time of the year, the hottest month of the year. I'm not one bit surprised to hear that seven horses have died of dehydration. It's what we've warned."
The mustang deaths came two days after In Defense of Animals joined ecologist Craig Downer in filing an appeal to try to block the roundup in an area known as the Owyhee complex, three management areas covering 750 square miles north of Elko. The appeal argued the roundup should be postponed until after Aug. 15 because it would subject young foals and mares to life-threatening conditions.
The groups ramped up their criticism Monday.
"That the BLM refused to even postpone this roundup knowing full well the life-threatening nature of conducting them during the hot summer months in desert country is yet another example of this agency's unwillingness to change," said Todd Tucci, an attorney with Advocates for the West, a public interest law firm that filed last week's appeal.
"The Interior Department must halt all summer roundups before other horses are subjected to similar inhumane treatment and conditions," he said.
Heather Emmons, a BLM spokeswoman in Reno, said the water holes in the range had withered to mud puddles in recent weeks. She said an aerial survey showed some bands congregating around a dwindling hole, though other water was within migrating distance.
"That's the hard part with wild horse behavior," she said. "If they don't migrate, look for something else, they'll stand there and wait."
The BLM said 32 horses were herded about a mile from a temporary holding corral, and another 196 were driven about eight miles.
Emmons said the animals would be kept at the temporary pens and given food and water until veterinarians determine they are stable.
The BLM had said it intends to remove up to 1,200 horses from the area.