KALAMAZOO, MI --

As he's done for nearly a decade, Mack hung out with regulars at

and

on Sunday where they offered him one of his favorite snacks.

But the nearly 13-year-old German Shepherd/Collie mix, a fixture at the popular two-story Irish pub and restaurant in the Vine Neighborhood, didn't have the appetite.

"He wouldn't even eat bacon and that's when the alarm bells went off," O'Duffy's Pub/Cosmo's Cucina owner Jamie Kavanaugh said.

On Tuesday, Kavanaugh took Mack to the veterinarian where tests revealed a large tumor on his liver, as well as other complications. The relaxed, gentle dog known to wander the pub is expected to be euthanized on Friday as "his body is shutting down," Kavanaugh said.

Kavanaugh said Mack is a certified training dog, meaning he passed a series of tests and is allowed in an establishment that also serves food. He spent most every day of the last 10 years at the business. His demeanor meshed with customers, who will be filling the pub next weekend for St. Patrick's Day, one of the busiest days of the year at O'Duffy's.

"He's been a big, calm boy for all of his life. He's very laid back, good with other dogs, people, kids. He's very tolerant and loving," Kavanaugh said. "He's enjoyed being here. He makes his rounds, eats some treats. St. Patrick's Day won't be the same without him."

Since receiving news of Mack's declining health, Kavanaugh said he's showered the dog with companionship and treats, including meatballs from nearby Martini's Pizza and steak bones. Kavanaugh brought Mack to O'Duffy's on Wednesday night where several customers stopped by to say goodbye. Kavanaugh said at points, it was standing room only. One customer ordered a filet and gave the first bite to Mack.

Kavanaugh said he plans to bring Mack to the pub, 804 W. Vine St., at around 5:30 p.m. on Thursday for one last night.

"The number of people who love this guy, I can't imagine what the actually number is. It's people I don't even know who love him, that come here and enjoy his company. It's a real testament to the love of this community," Kavanaugh said.

Kavanaugh struggled to describe how important Mack has been to him for the last two years. Jamie Kavanaugh's wife, Kim, who also owned the businesses,

. She was well-liked and respected by many of their patrons and area restaurateurs.

"When my wife passed away a little more than two years ago... I was really afraid he was going to follow her. Instead, he stuck by my side, stayed by my side and he's been with me on this journey ever since. Now, I think he feels his work is done. And he's tired. All I can do is pass the love on," Kavanaugh said.

Kavanaugh said he plans to have Mack cremated, but isn't sure what he'll do with the remains. He's considering taking Mack to Ireland and "scattering a little bit of his ashes off the coast of the Irish Sea at a very special place."

John Liberty can be reached at 269-370-7372 or jlibert1@mlive.com. Follow me on Twitter @JohnTLiberty