BAKERSFIELD, Calif. -- Pet shelters are filled with unwanted pets. But Tuesday is National Spay Day -- the day people can help control pet overpopulation.

People like puppies or kittens, but too many puppies and kittens are being born without a loving home to go to, reported KERO-TV in Bakersfield, Calif.

Statistics show that 7,000 puppies and kittens are born every day in the United States, and 4 million to 6 million pets are euthanized every year because they are homeless, the television station reported.

"Abandoned animals are suffering and are sometimes starved, injured, and terrified," said Ron Faoro, president of the California Veterinary Medical Association. "When brought to shelters, they are often unadoptable and are euthanized."

The Humane Society and other pet-friendly organizations encourage the nation to come together to spread awareness about this problem and get their pets spayed or neutered on Spay Day.

"And there are more consequences of uncontrolled breeding than just the loss of pet lives," Faoro said in a news release. "Abandoned and stray companion animals pose a health hazard to humans and other animals. They are also subject to cruelty and add to public costs of sheltering and euthanizing."

Last February, 29,000 cats, dogs and rabbits were reported spayed or neutered in 315 Spay Day USA events hosted around the country, according to the Humane Society.

The organization also said many veterinary clinics offer discounts or even free spay and neutering service in honor of National Spay Day.

Spay Day was established in 1995 by the Doris Day Animal League, which combined its operations with the Humane Society last year.

Additional Resources:

• The Humane Society of the United States
• California Veterinary Medical Association