KAILUA, KONA, Hawai'i — The brown and white painter horse had been abandoned in a Hawi field for more than a year when the Humane Society got a call this summer.

The horse had a weepy eye, but otherwise just seemed in need of some good care before he could be adopted like the hundreds of cats and dogs that pass through the Big Island's three animal shelters.

"We'll call him Amigo. He looks like a tough guy," said Natalie Tavares, manager for the Waimea Humane Society shelter after seeing the horse for the first time.

Organizers of the Hawai'i Horse Expo 2008 in Waimea hope to raise awareness about horses like Amigo, one of a growing number of horses that are being abandoned, abused, neglected and mistreated on the Big Island.

Proceeds will establish an Equine Fund to care for abused and abandoned horses on the Big Island.

"We have to develop public awareness of the problem here," said Nancy Jones, expo organizer and owner of Circle J Horse Sanctuary in Waimea. "Traditionally, people here got it, but somehow things have changed. Animals have become as disposable as Styrofoam cups."

Unfortunately, Amigo's story ended sadly.

Veterinarians diagnosed the 10-year-old with cancer, which started in his eye and spread throughout his head. He was euthanized on Wednesday.

Jones said the cancer may not have spread as far and become terminal if Amigo had been properly cared for.

"People don't want to read about stories like that, but it really shows what is happening," Jones said.

The expo, scheduled to last through today, offers lectures, panel discussions, live demonstrations, trail rides and farm tours. It will give horse riders and owners a chance to learn from the field's top experts.