CORVALLIS -- Some pet owners are barking mad about a fireworks display during Oregon State University's spring football game on Saturday.

The explosions panicked many dogs and spooked horses at OSU's 17th annual Pet Day, which hundreds of residents and their four-legged friends attended. Six dogs bolted from the event, and one was still missing Saturday evening.

Pet Day spokeswoman and veterinary student Nicole Tomps apologized to people who attended: "There are people very upset. We hate that it happened ... A lot of animals were affected."

Tomps said the veterinary college's dean's office voiced concerns in advance about the fireworks to the OSU athletic department. Pet Day is regularly held this weekend every year, said dog professionals in attendance.

Representatives of the OSU athletic department were unavailable for comment early Saturday evening.

The fireworks, at about 2 p.m., celebrated the groundbreaking for Reser Stadium's expansion, and were met with cheers at the football game.

The fireworks were listed on Pet Day's Internet schedule between 2 and 2:30 p.m., though fliers at the event didn't mention them. Warnings were given at Pet Day and in newspaper articles about "Raising Reser."

Regardless, some people were surprised. So were their pets.

Dogs dragged owners, tried to bite their way out of metal crates, crashed and clawed through holding pens and ran into roads, witnesses said.

Nan Link of Corvallis, of Best Friends Obedience and Agility School, said she and two friends held down her golden retriever to keep it from escaping.

"We were invited by OSU to be here. We do not deserve to be treated that way. They knew there were going to be all these animals here," said Julie Flanery of Philomath, who had two dogs scatter and nearly drove over one of them.

Even two hours later, pets were edgy and some could be permanently traumatized, owners said.

"For a lot of us, this is our lives. This is what we do," said Greg Gustafson of Border Collie International, a performing troupe of dogs from Corvallis.

Five Oregon State Police troopers and an OSU public safety officer helped veterinary students and attendees search for missing dogs.

Pet Day, which includes a pet photo contest, a canine obstacle course, Frisbee competition and other events, is a fund-raiser for the veterinary college. Each year, it brings in about $4,000 dollars for scholarships and the college, Tomps said. She added it's held mostly for the fun it usually brings.