JEFFERSON CITY, MO. - Missouri voters thought they scored a big victory against some of the nation's most notorious puppy mills when they approved strict new dog breeding regulations last year.

Now state lawmakers are changing the rules.

A state law aimed at cracking down on disreputable breeders and improving animal care has been overhauled by lawmakers who say that the voter-approved version is too costly and that it punished legitimate dog breeders who generate an estimated $1 billion annually in the state.

Animal advocates complain elected officials are overruling the will of the people, and some are prepared to put the issue on the ballot again next year.

Wayne Pacelle, president of the Humane Society of the United States, said public confidence is undercut when about 100 lawmakers change a law backed by about 1 million voters.

"The effort in Jefferson City is a piece-by-piece dismantling of every core provision," Pacelle said.

State Rep. Jerry Nolte, who represents part of a county that passed the ballot measure, said he voted for the overhaul bill because it would help protect dogs by increasing funding for enforcement. "What I was trying to do was interpret what the voter intent was, and what they wanted to do was to lessen the suffering of these animals," said Nolte, a Republican. "And I believe that this, on balance, will reduce the suffering of these animals."

A spokesman for Democratic Gov. Jay Nixon said Thursday the bill would get a careful review and declined comment on whether he planned to sign it.

Swayed by breeders who argued the law would close them down and concerned about possible future regulation for other agricultural industries, a bipartisan group of mostly rural lawmakers voted to change most of the voter-approved law's provisions. For example, a 50-dog cap is scrapped, but breeders would pay more to boost state oversight of the industry.

The voter-approved measure "is just going to put the law-abiding, licensed, legitimate, conscientious, caring breeders out of business, and the only ones remaining will be the illegal people already flying under the radar," said Mindy Patterson with the Missouri Federation of Animal Owners.