RIVERSIDE (CBSLA.com) — Riverside County supervisors set a public hearing date to consider a public safety ordinance mandating sterilization for pit bulls in unincorporated communities.

The supervisors voted 5-0 Tuesday to further discussion of the ordinance, which would require pit bulls older than four months to be sterilized.

Under the proposed measure, an animal could only be exempted from the law if the owner could prove that the dog belongs to a registered breeder, is trained for law enforcement duties, serves as an “assistance dog” for a disabled person, is in training or licensed in another county or has been certified by a veterinarian as having a health defect that would be aggravated by sterilization.

The purpose of the proposed ordinance is to “protect the public’s health and welfare from irresponsible owners of pit bulls by mitigating the over-population of unwanted pit bulls,” the Department of Animal Services said in a statement.

Pit bulls “historically have very low redemption or adoption rates,” according to department director Rob Miller, who said 20 percent of dogs impounded and 30 percent of animals euthanized in Riverside County are pit bulls.

“We tend to see that many owners of pit bulls are not responsible,” said Supervisor John Tavaglione, who called for tougher penalties against owners in April after an 84-year-old man was mauled by a family pit bull while seated in a wheelchair.

In February, two pit bulls killed their 91-year-old owner in Hemet. A French Valley man was seriously mauled by his son’s 90-pound Mastiff pit bull mix in June.

Two people were arrested in neighboring San Bernardino County Tuesday after a two-year-old boy was mauled to death by five pit bulls while allegedly under the suspects’ care.

Critics of the ordinance have complained in the past that the breed was unfairly targeted and had been “sensationalized.”

Veterinarian Melanie Verrault warned the board of “anti-breed legislation” Tuesday, saying the ordinance could make pit bull owners less willing to seek licensing, training or medical attention for their dogs out of fear of receiving a penalty if the dogs are not spayed or neutered.

“The ordinance in general is to reduce the number of animals that are in our shelters, and there are a lot of pit bulls in our shelters and there’s also a lot of chihuahuas in our shelters,” Verrault told CBS2.

Victims of pit bull attacks argue the breed has a vicious streak that makes them inherently dangerous.

A public hearing is set for Oct. 8.

(©2013 CBS Local Media, a division of CBS Radio Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Wire services contributed to this report.)