HARRISBURG (AP) _ Sammy, a Shetland sheepdog, wouldn't touch his food, but instead retreated to a corner of the yard, paced in circles, and dug up and devoured mouthfuls of dirt — behavioral oddities that owner Linda Eroh later learned came from a lifetime of maltreatment Sammy endured as a "stud" in a large dog-breeding operation.

The 10 years of caged confinement Sammy endured would be illegal under a bill signed late Thursday by Gov. Ed Rendell. The governor, who owns two rescued golden retrievers, and dog advocates hope the new law will help Pennsylvania shed its reputation as the "puppy mill" capital of the East.

The Humane Society of the United States has counted Pennsylvania among a handful of states where lucrative, largely unregulated puppy mills are concentrated.

The issue caught the attention of Oprah Winfrey after a suburban Philadelphia rescue organization put up a billboard in Chicago begging her to do a show on dog breeder abuse. And the movement took on new momentum when, in August, operators of two eastern Pennsylvania kennels shot 80 dogs after being ordered to let veterinarians examine some of them.

The new law imposes strict standards on commercial kennels, including at least twice-a-year veterinary exams, larger cage sizes and exercise requirements.

"We've catapulted ourselves into having one of the best laws in the country," said Sarah Speed, the Humane Society's Pennsylvania state director.

At least three other states have passed crackdown measures this year. New laws enacted in Virginia and Louisiana limit the number of dogs that can be housed in kennels, and Arizona law enforcement officials were given the power to impose a $50 fine against anyone caught selling animals along public roads or in public parks in urban counties.

The new law Pennsylvania would target about 650 large-scale commercial breeders, or roughly one-quarter of the state's 2,600 licensed kennels, that sell any dogs to dealers and pet shops or traffic in at least 60 dogs per year. Violators would be subject to both criminal and civil penalties.

The law also gives dog wardens the authority to act on alleged violations, a power previously given only to police and humane officers. Also, only veterinarians will be allowed to euthanize dogs in commercial breeding kennels.

Rendell's administration had initially pushed in 2006 for regulatory changes. It abandoned the effort amid criticism that the mandates were too costly and applied a "one-size-fits-all" approach to home-based breeders and large commercial operations.

This year, Rendell pushed for a new law over the objections of farmers and dog breeders.

The cost of larger cage sizes and exercise areas could drive some kennels out of business, said Mark O'Neill, spokesman for the Pennsylvania Farm Bureau.

The new law is also stricter than federal inspection standards to which kennels are subjected, said Ken Brandt, lobbyist for the Pennsylvania Professional Dog Breeders' Association, which represents about 400 breeders.

"Quality breeders got shortchanged by the ones that have not been operating properly," Brandt said.

Winfrey gave the issue national exposure earlier this year in a show investigating abuses at puppy mills. Bill Smith, the founder of Main Line Animal Rescue in Chester Springs, said his organization paid about $10,000 to $12,000 for a billboard on a Chicago highway to attract her attention.