WASHINGTON - Pet food labels that indicate the number of calories per serving could help obese animals shed the extra pounds, a veterinarians' association recommended to the Food and Drug Administration on Tuesday.

"Pet owners do not always know how much to feed. They may not realize the high number of calories associated with some of the pet food they are giving their pets," said John Branam, testifying on behalf of the American Veterinary Medical Association.

The FDA held the hearing as part of legislation passed last year that requires the administration's Center for Veterinary Medicine to establish pet food labeling standards in two years.

According to the AVMA, 54 million pets in the U.S. are obese, an "epidemic" that the association says is growing at an alarming rate.

But Nancy Cook, vice president of the Pet Food Institute's technical and regulatory affairs, said that calorie labels are unnecessary and won't prevent obesity in pets.

"It doesn't work for people," said Cook, a voice for the industry's manufacturers.

The labels already contain serving sizes based on a pet's size. Calorie information can be obtained from food manufacturers, she said.

But the AVMA said that it's not consumers' and veterinarians' jobs to track down manufacturers for that information.

A standard nutritional label that lists the number of calories per weight of food and per household item such as a can or a cup would prevent owners from overfeeding their pets, the veterinary medical association said.