An audible gasp filled a Sonoma County courtroom this week when a photo of a severely underweight dead horse flashed on-screen during a felony animal cruelty trial.

The 28-year-old horse, named Yiyo, was found dead in its stall on a Bloomfield property Nov. 26, 2007, from what prosecutors allege was neglect and abuse at the hands of owners Laura Valencia and Salvador Barrera, both 35.

Valencia and Barrera face a maximum of three years in prison on the felony charge, prosecutor Marianna Green said, and possible fines. They have pleaded not guilty and remain out of custody during the trial.

The couple are facing one felony animal abuse charge in Yiyo's death and three misdemeanor charges in connection with the treatment of two other horses and a dog found on the property when Animal Control officers responded to the dead horse.

The other horses, Jack and Katie, survived and were adopted into new homes after being rehabilitated by a local horse-lovers group called CHANGE, Coins to Help Abandoned and NeGlected Equines, said group member Katie Moore.

Valencia's attorney, David Sherer, denies his client abused Yiyo. Barrera's attorney didn't return a call seeking comment.

Veterinarian Grant Miller testified Tuesday that the horse weighed less than 800 pounds, about 350 pounds under normal weight. He said there was no food or water in the stall and that Yiyo may have resorted to eating feces.

Miller showed photos of other horses considered in ideal health, then showed a picture used in veterinary medical circles to illustrate a severely emaciated animal.

Yiyo's corpse was in a similar state of malnutrition, Miller told jurors, with bony points protruding around its ribs, hips, spine and withers, areas that have healthy fat deposits in a properly cared-for animal.

Yiyo died of colonic torsion, a twisting of the intestine, both sides agree. The painful condition, also called "twisted gut," is treatable, according to the equine health center at the University of California Davis veterinary school.

Sherer maintains the defendants did not mistreat Yiyo and that the medical condition is fatal and common to old and young horses.

"They didn't do anything wrong," he said. "The horse died from a natural cause."

The criminal charge alleges the couple failed to provide sufficient food and water and subjected the horse to unnecessary suffering.

Miller testified that a water pail found near the stall had a layer of "dry dirt" at the bottom. In the dirt surrounding Yiyo's body, he said there were marks in the dust similar to "snow angels," that were consistent with the horse struggling while it was down.

The horse also had several deep abrasions and "extreme bruising" on its eyes, head, knees and feet on both sides of the body. The stomach was empty except for about two cups of acidic liquid, he said, in a cavity that can hold about three gallons of food.

A necropsy showed "not an ounce of fat," in the horse's abdominal wall, Miller testified.

A properly fed horse will defecate about 12 times a day, Mil-ler said. There were no droppings in Yiyo's pen.

More than a dozen horse enthusiasts are attending the trial, hoping to encourage aggressive prosecution of suspected animal cruelty cases.

A neighbor testified Monday that she heard thrashing and banging from the stable the night before Yiyo was found dead. Her call prompted animal control officers to discover Yiyo's body the following morning.

Sherer declined to be more specific in his client's defense, saying more will come out in court as the trial continues. He denied allegations that the defendants failed to provide food and water to the animals.

"That's not true, and it had nothing to do with the death of the horse," he said.

The prosecution rested Thursday. Barrera was expected on the stand to continue testimony this afternoon.

You can reach Staff Writer L.A. Carter at 568-5312 or lori.carter@pressdemocrat.com.