A Windsor man accused of starving a former race horse to death won't serve jail time under a plea bargain with prosecutors Friday that angered animal rights activists.

Mark Ross, 49, was charged with felony animal cruelty in the death of Skimtheexcess, a six-year-old thoroughbred that died on his family's Jensen Lane ranch in 2010.

Advocates said it was allowed to starve beside another horse that received regular feedings. An indentation of the gelding's rib cage was left behind when its emaciated body was pulled from the mud.

On the eve of trial, Ross accepted a prosecution offer that reduced his charge to a misdemeanor in exchange for a $500 donation to a horse rescue group and 200 hours of volunteer work. He also was ordered not to keep horses during his three-year informal probation.

Horse activists who attended his hearing criticized the punishment as a "wrist slap." They heckled Ross as he left the courthouse with taunts of "You got off cheap" and "We'll be watching you."

"What happened to that horse was an atrocity," said Petaluma activist Siobhan Duff.

Ross said he didn't intentionally kill the horse, which was owned by his niece. He switched its food to alfalfa on the advice of an expert and allowed it to graze in an open pasture.

When it collapsed one night, he said he was shocked.

"It was like losing a family member to us," Ross said after the hearing. We did try to help that horse. It's absurd to suggest we didn't."

His niece, Nicole Ross, 29, pleaded no contest last fall to felony animal cruelty and was ordered to serve 45 days in jail.

District Attorney Jill Ravitch said Friday that Mark Ross' punishment was appropriate given his role in the case. He faced up to three years in jail if convicted of the original charge, she said.

"This is about accountability," Ravitch said. "It's also about sending a message to the community that if you can't care for an animal, call someone to assist you. Don't just leave them to die."

Horse lovers said it was among the worst cases of animal neglect in Sonoma County in recent years.

A veterinarian testified at a preliminary hearing that Skimthexcess, which was raced at Bay Area tracks, was about 500 pounds under weight when he died.

Katie Moore, executive director of CHANGE, Coins to Help Abandoned and Neglected Equines, said a necropsy revealed the horse had depleted its fat reserves by not being adequately fed.

Its bone marrow content — a common measure of horse nutrition — was found to be just 2 percent when it should have been closer to 90 percent, she said.

She said the horse died beside an Arabian horse that was boarded next to it.

"The horse absolutely starved to death," said Moore, whose organization will get the $500.

You can reach Staff Writer Paul Payne at 568-5312 or paul.payne@pressdemocrat.com.