SACRAMENTO, Calif. (AP) _ In the West, where they used to hang horse thieves, rustling is rising.

''What we believe is causing the rise ... is the increasing cost of the horses on the hoof,'' said Placer County sheriff's inspector Johnnie Smith. ''Horse meat is considered a delicacy in the European and Japanese cultures.''

Sold at regional auctions throughout the country, with little proof of ownership required, the erstwhile cowboy's companion can bring up to 70 cents a pound, a profitable venture for a thief who can haul a 1,000-pound animal.

''There's been a huge increase in horse thefts, considering the number of calls we get from people looking for help,'' said Debbie Tiernan, president of Horse Power Sanctuaries Inc., a northern California citizen group.

The group receives reports of thefts at least weekly, up from an occasional call only months ago, she said.

Horse Power is backing bills before the California Legislature aimed at identifying stolen horses better and ensuring humane treatment. The bills also discourage so-called ''killer buyers'' - people who claim they're giving a pet a good home, then sell it for slaughter.

Particularly upsetting to horse lovers in rodeo country, where sheriffs still muster posses, is the thought of the stolen animals ending up as entrees.

''Nobody in this country is interested in eating Trigger or Silver,'' said Vickie Williford of Beltex Corp., a Fort Worth, Texas, plant that slaughters about 50,000 horses annually for export to Europe.

Horse meat became popular in Europe during World War II shortages. Federal officials say the current demand has made it the biggest U.S. meat export to the 12-nation European Community. It is particularly prized in France and Belgium, where special butcher shops feature it.

While horse meat exports remained constant in 1989 and 1990 at about 125 million pounds annually, the value increased more than 15 percent from $134 million to $156 million, Commerce Department officials said.

Representatives of slaughterhouses said they are providing a humane end for animals that might otherwise die protracted deaths of neglect. They say they do not knowingly buy stolen horses.

But they add that few means, such as brands, exist to protect against that.

''How would we check to see if they are stolen?'' said Williford, secretary to the president of Beltex.

Figures are difficult to ascertain on the rustling problem, which nowadays is reported under the prosaic term of grand theft felony, a broad category.

Sheriff's officials in six counties near Sacramento, where detectives exchange information monthly, said horse rustling has increased from almost none to dozens of cases over the past 18 months.

Recently in Placer County, two stolen horses were traced to an auction, then bought back by their owners from a Texas slaughterhouse.

Fort Worth's Beltex cooperates with owners looking for their horses, Williford said. If a stolen animal is located, the plant goes back to the party that supplied the horse, tries to get its money back, and places the matter in the hands of local law enforcement officials.

But Ursula Liakos of the Hanging Tree Committee, a national network of activists who try to track down stolen horses, maintains that horse thefts and the horse slaughter trade are interwoven.

''The industry, in order to fill a quota, will acquire horses in any old which way it can,'' she said.

Many horses are headed for slaughter because their owners, caught in the economic recession, can no longer afford to keep them, activists said. A change in tax laws also has ended some benefits of owning horses.

Petition drives are under way in the United States and Europe to secure a ban on horse meat exports to European countries until reforms are enacted, Liakos said.

''In the olden days, they hung people for stealing horses,'' Liakos said. ''We can't hang them anymore, but there are other things we can do.''