An unusually early and extreme snowstorm over the weekend caught South Dakota ranchers and farmers unprepared, killing tens of thousands of cattle and ravaging the state's $7 billion industry -- an industry left without aid because of the federal government shutdown.

As many as 75,000 cattle have died since the storm battered the western part of the state Thursday through Saturday with snowfall that set records for the entire month of October in just three days, officials said.

State-wide snow totals averaged 30 inches, with some isolated areas recording almost 5 feet, The Weather Channel reported.

The South Dakota Stock Growers Association estimated that 15 percent to 20 percent of all cattle were killed in some parts of the state. Some ranchers reported that they lost half or more of their herds.

The storm was accompanied by hurricane-force wind gusts, especially Friday night, which drove some herds seeking shelter miles from their ranches. A trail of carcasses left a gruesome sight, said Martha Wierzbicki, emergency management director for Butte County, in the northwestern corner of the state.

"They're in the fence line, laying alongside the roads," Wierzbicki told The Rapid City Journal. "It's really sickening."

Ranchers have no one to ask for help or reimbursement. That's because Congress has yet to pass a new farm bill, which subsidizes agricultural producers.

And even if there were a farm bill, the government shutdown means nothing could be done under one anyway.

State Agriculture Secretary Lucas Lentsch called the early-season blizzard "devastating to our producers," saying his agency was trying to figure out a response.

In the meantime, he said, the best farmers and ranchers can do is meticulously document their losses, with detailed photos, for use when and if claims can be processed.

The most immediate concern is proper disposal of the dead livestock, which state law says must be burned, buried or rendered within 36 hours for the health of not only of surviving herds but also for people.

"That can be a significant source of disease spread, so we want to make sure those carcasses are burned, buried or rendered as quickly as possible," Dustin Oedekoven, South Dakota's state veterinarian, told the Journal.

The storm will leave its mark on surviving herds, according to the South Dakota State University Agricultural Extension Service, leaving the remaining cattle vulnerable to diseases like infectious bovine rhinotracheitis, bovine respiratory syncytial virus and bovine viral diarrhea virus.

Most of the diseases have incubation periods of a week or two, so those problems can't yet be assessed, the extension said.

"This is absolutely, totally devastating," Steve Schell, a rancher in Caputa, near Mount Rushmore, told the Rapid City news.