A bill that would require the sterilization of most dogs and cats in California was sidelined Wednesday until next year after senators failed to endorse it.

The bill's author, Democratic Assemblyman Lloyd Levine, withdrew his proposal Wednesday rather than have it fail in the Senate Local Government Committee, where it did not gain support during a hearing Wednesday.

The measure would have required most pet owners to sterilize their dogs and cats by the time they are 6 months old or face a $500 fine.

Licensed breeders would be exempt if they applied for a permit from their local animal control authority. Other exemptions included owners bringing animals to the state temporarily for competitions and dogs used for law enforcement, hunting, farmwork and livestock herding.

Critics included breeders, service organizations and rural governments. Professional breeders said the bill would unfairly target them and would do little to address "backyard breeders" who flout existing animal welfare laws.

Levine said he would narrow the bill so it would apply only to owners who let dogs or cats roam free or who violate animal welfare laws. But he said pet overpopulation is still a problem that needs to be solved.

"We've got six months to work and educate the committee," Levine said.

The legislation was crafted primarily by animal shelter workers as a way to reduce the cost of housing and euthanizing the state's unwanted animals. About a million dogs and cats are sent to California animal shelters each year and about half are euthanized for lack of homes.

More than 100 people and several dogs packed the committee room for the culmination of a three-day lobbying effort at the Capitol. Retired "Price is Right" game show host Bob Barker and actor Jon Provost, who played Timmy on the television series "Lassie," were among those who lobbied on the bill.

At least 25 states require that dogs and cats adopted from shelters be sterilized. Last year, Rhode Island passed a law requiring cats to be spayed or neutered by six months of age. Denver; Camden; N.J.; New York; and Fort Wayne, Ind., are among cities that have some kind of sterilization law.