ST. LOUIS – Until recently, Oklahoma rancher Ryan Payne, 37, wasn't worried about anyone stealing or killing his cows and calves. His pasture is so far off the beaten path “you need a helicopter to see it,” he said in a report from The Associated Press. But that changed last month when he found piles of entrails from two Black Angus calves he said thieves gutted. They had stolen the meat and another 400-lb.calf he estimated cost him $1,800.

High beef prices have made cattle attractive for stealing by certain people struggling in the sluggish economy. Six-thousand lambs were stolen from a feedlot in Texas, and nearly 1,000 hogs have been stolen in recent weeks from farms in Iowa and Minnesota. These thefts total millions of dollars in losses for US ranches.

Today's thieves are sophisticated compared to the horseback bandits of the yesteryear, authorities claim. In the middle of the night, they pull up with livestock trailers and know how to coax the animals inside. Investigators figure it is then a quick trip across state lines to sell the animals at auction barns.

"It almost has to be someone who knows about the business, including just knowing where to take the cattle," said Carmen Fenton, a spokeswoman for the 15,000-member Texas and Southwestern Cattle Raisers Association.

Theft statistics among certain states are huge. In Texas – the nation's biggest cattle producer – and to a lesser extent Oklahoma, some 4,500 cattle have been reported missing or stolen this year alone, according to Fenton's group. The association's special rangers managed to recover or account for $4.8 million in stolen ranch property each of the previous two years, most of it steers, bulls, cows and calves.

Investigators have found clues to be elusive, partly because thieves often artfully conceal their crimes by replacing pasture fences they've cut to get to the animals, Thomas said. Ranchers may not realize any are missing for a week or more, and by then, any tire tracks or other evidence may be gone.

Although brands are widely used in the West, Missouri, Oklahoma and Texas don't require them. Although a voluntary national livestock identification system exists, few ranchers and farmers participate in it.

All’s not lost, though, as owners' vigilance occasionally pays off. A Colorado rancher hunting prairie dogs spotted one of his branded, missing cows on another man's property. Deputies swooped in and found 36 cows and 31 calves worth $68,000 and belonging to nine different people.

One Ohio woman has been charged with stealing $110,000 worth of frozen bull semen – which can be valuable to breeders in even small amounts – from a liquid-nitrogen tank at a Moorefield Township genetics company where she once worked.