Sherry Shumaker has grooved to "Dancing Queen," "Wild Thing" and "Doo Wah Diddy" with her dancing partner Heidi -- a Doberman pinscher.

At a Woodbridge studio, Heidi has taken lessons in standing on her hind legs, walking backwards and spinning, all in time to music and in sync to Shumaker's dance steps.

Shumaker, 43, a systems analyst who lives in Fairfax County, confesses to spending a "ridiculous" amount of money on her three dogs, giving them such luxuries as acupuncture therapy and organic food.

"I just wish I could use them as a tax deduction every year," she said, laughing. "They're worth every penny."

Last year, pet owners across the country spent plenty of pennies -- $34.4 billion -- caring for their pets, more than double the $17 billion a year spent a decade earlier, according to American Pet Product Manufacturing Association Inc., a Greenwich, Conn.-based trade association. Much of that cash went for routine veterinary visits and over-the-counter food, but more owners are paying for toys, gourmet biscuits and a nice haircut, as well. Cats outnumber dogs, but more of the money is going to the dogs.

Reflecting the trend, services for dogs have become big business in the Washington region, where suburbanites caught up in long commutes and unable to spend much time with their dogs make it up by shuttling them to day care, dance lessons and swimming classes.

"The owners are treating their pets more like family members," said Robin Bennett, who owns All About Dogs Inc. in Woodbridge. Her business specializes in obedience and agility training, including the freestyle dance class that Shumaker takes her dog to.

Besides special services, people also splurge on pricey products for their pets.

That's why companies that once served only humans now consider their animal companions their customers, as well. Paul Mitchell, Omaha Steaks and Harley-Davidson are among the companies extending their brands to pets by offering shampoos, treats and attire, respectively.

Rebecca Kalch carries brand-name pet clothing, leashes and collars at her Four Paws Bakery Inc. in Occoquan. For example, there's the Ruff Wear clothing line, including boots. "This is for the canine that's going places," said Kalch, who also sells polos to match an owner's shirt.

Her bakery, which opened in November, makes Barkday and Bark Mitzvah cakes for those special occasions. Kalch is trying to get other boutique pet stores to carry her homemade treats -- with names like Pupparoni and PNut-Butter Pudy-Tat's -- and pet meals that she learned to make for her cat Mouse, who suffered from diabetes.

Kalch is breaking even on her expenses and sales, which she didn't expect to happen until the end of this year. She attributes some of her sales to couples with fewer or no children, along with senior citizens purchasing treats for their "grand dog" or "grand kitten."

"They realize that that's all they're getting so they might as well spoil something!" Kalch said.

Shumaker says she organizes her life to accommodate her two rescued Doberman pinschers, Heidi and Sable, and her cocker spaniel, Hobbes. She and her husband were thinking of their dogs when they chose their Subaru Outback, their pickup and their Fairfax home with its large yard.

Pet acupuncturists and chiropractors make regular house calls. When five-year-old Heidi broke a tooth, she had a root canal. The elderly Hobbes, now 16, requires the most medical care, including his own cardiologist.

"He has more doctors than I do to keep up with him," Shumaker said.

She tries to reduce expenditures on her pets by frequently making their food, adding organic meats and produce to the mix.

With Heidi already a dancer, Shumaker plans to enroll Sable in the next freestyle class offered at All About Dogs. "It's a lot of obedience as well as putting some fun and music to it," said Shumaker. "It's kind of our time together."

The classes are taught by computer technician Susan Brogan as a hobby. The Nokesville resident sometimes dons a Spanish-style costume while her Australian shepherd, Jazz, sports a color-coordinated collar.

In the late 1980s, dog day-care facilities began appearing on the East and West coasts, said Susan Briggs, co-owner of Houston-based Urban Tails, who is leading an effort to establish operating standards through the American Boarding Kennels Association, based in Colorado Springs.

Now, there are more than 1,500 dog day-care centers, including some operated by such giants as PetSmart and Petco, serving pet owners seeking exercise and socialization for their dogs, Briggs said.

In the past two years they've been growing quickly, spreading from urban areas to the suburbs and charging at least $25 a day for the service.

"I'm not that surprised it keeps growing, and it keeps going farther out because commuters keep going farther out," said Rebecca Bisgyer, a former corporate executive who opened the District's Dog-ma Day Care and Boarding for Dogs in 1998. "I would say that it's probably growing much faster in the suburbs than in the city."

Jessica Rockx, manager of the Waggin' Tails Junction in Manassas, says many of her day-care customers are office workers, teachers and government contractors who spend long days working and commuting and are too tired to exercise their dog or play with their rowdy puppy in the evenings.

"I think they feel guilty," said Rockx, as boxers, retrievers and pit bulls climbed up and down a child's plastic playground set, caught tennis balls and occasionally fought over a toy to the sounds of country music.

Formerly called Lake Jackson Kennels, where customers stowed their pets while on vacation, the company now provides day care to at least a dozen dogs a day.

Bristow resident Thomas Murphy and his wife take their puppy, Sir Duke Duncan, there. Murphy, 45, works as a systems engineer in Alexandria while his wife works as a technical writer in Reston.

"Me and my wife thought he needed to be social and didn't want him to stay home all by himself for eight or nine hours," said Murphy, who typically drops his golden retriever off at Waggin' Tails before boarding the train.

MaryAnn and Michael Settlemyre, who moved to a neighborhood near Manassas National Battlefield Park more than four years ago, take their chocolate Labrador to the Yappie Cuttery, a dog spa in Manassas Park.

When they adopted Bailey, they discovered he was "deathly afraid of water" -- even a puddle, said MaryAnn Settlemyre, 38. Bathing the three-year-old left the couple more soaked than their prized pooch, so they enrolled him in Yappie's canine swimming classes.

"We're the first people to take some teasing because we're taking our dog to swimming lessons," said MaryAnn Settlemyre, a Fairfax County teacher who doesn't have children.

But the couple didn't want Bailey to be terrified during a vacation to a beach or lake.

Like proud parents, they watched from behind a glass wall as obedience trainer Kim Sewell cajoled Bailey into the 40-foot-long pool during his first swim lesson.

The couple also indulge their dog with toys, expensive food and private obedience lessons. MaryAnn Settlemyre jokes that Bailey -- who was rescued from an abusive home -- is a "thousand dollar rescue dog" because they spent nearly $1,000 on an invisible fence for their back yard. Swim classes cost at least $20 a lesson. Now that Bailey has scored well on his personality evaluation, he'll start attending day care at least once a week.

"If you are going to have a dog and take care of him appropriately, it can be costly," said MaryAnn Settlemyre. "I think an animal is a luxury."

In April, Peter Perretta, owner of Yappie, transformed his grooming business into a pet resort, housing it in a fancy lodge with granite floors in the lobby. The building dwarfs the children's day care next door.

Perretta sells spa packages that include a 30-minute run on an underwater treadmill. Suites for overnight guests include beds. Yappie hosts birthday parties to which dogs can invite their closest canine pals. At the day-care center, they can watch episodes of Lassie or classic Benji movies on satellite television.

"A few years ago, I wouldn't have done it," Perretta said. "The mentality has changed in the past five years to the point where people are ready to pay the money for the service."

Of course their dogs are worth it, owners say.

"When we come home, there's nothing better," MaryAnn Settlemyre said. "He's excited to see you."

Scott Gearhart puts Nilla, a Labrador retriever, through a series of agility drills during a training session at All About Dogs in Woodbridge. Kim Sewell takes Bailey, a chocolate Labrador retriever with a distrust of water, for a swim at the Yappie Cuttery in Manassas Park.Rebecca Kalch, owner of Four Paws Bakery, has been surprised at the rapid success of her Occoquan business, which opened in November.