Fourteen-year-old Murphy hisses and growls as Dr. Barb Rossi tries to draw blood from her leg to find out if the cat's kidney failure has progressed.

Rossi has put a muzzle on her and owner Peggy Vanco is holding her on a bed in her Glendale home. Vanco also has two other cats and a springer spaniel that got checkups.

"It's just much more convenient for me and I think the animals react better to have her come rather than going to a vet's office, especially the cats," Vanco said.

Rossi is part of a growing number of veterinarians who make house calls because of the low overhead costs and the freedom that comes with it.

"For older people, for people with disabilities, for animals that hate to go in, it's really nice and it helps me to see animals in their own environment," Rossi said.

Shannon Stanek, president of the 30-year-old American Association of House Calls and Mobile Veterinarians, said the profession is experiencing a revival: Membership has doubled to about 300 members over the last 10 years. She also has received more inquiries lately.

She estimated about 70 percent of her members work out of their cars and the rest have mobile units — recreational vehicles where they perform surgeries, dental exams and X-rays. Two companies that make the mobile units are also seeing an increase in demand.

Stanek, who is based in Pottstown, Pa., estimated that about 5,000 vets make house calls nationwide in both rural areas and big cities.

Stanek, 36, has visited homes for about nine years within about 20 miles of her home.

Her business has grown 15 percent to 20 percent each year and she is looking to add an office to her practice in case her clients need emergency services or medications.

Dr. Michael Andrews, president of the American Animal Hospital Association, said people think more highly of their pets than 15 or 20 years ago.

"We've shifted away from a more agricultural and rural background and that's playing a role," said Andrews, who is based in Riverside, Calif.

People are also more willing to spend money on their pets, he said. What mobile vets charge varies — some charge more and others like Rossi charge less than an area clinic.

According to the American Pet Products Manufacturers Association, the amount pet owners spent more than doubled from $17 billion in 1994 to $36.3 billion in 2005 — an all-time high.

Spending on veterinarians has also increased from 7.1 billion in 2001 to 8.7 billion in 2005, according to the association.

The companies that make the mobile vet units, which cost $130,000 to $200,000 on average, have also seen demand increase.

Dennis Day, a vice president at Humboldt, Iowa-based Dodgen Industries Inc., said last year sales increased 12 percent and he's projecting a 6 percent increase this year.

Gahanna, Ohio-based La Boit has seen sales jump by an average of 30 percent each year for the last five years, said Vice President Jody Blais.

Dr. Lindsey Heard, who is based in Macon, Ga., had his own pet hospital for 15 years until 2002 when he got a La Boit mobile unit. Heard, 54, said he likes that he can set his own schedule and nets more money than before.

He said he tries to stay within a 10- to 15-mile radius, and his top services are spays, neuters, vaccinations and exams.

"I can do pretty much anything else anyone else can do in a practice except board," he said. "I love it. I never would go back."

Heard, who normally has an employee but currently does not, said he keeps his rates reasonable because he has little overhead costs. He charges $40 for travel and an exam, and everything else is extra — about what he charged at his clinic. His average bill is $175 to $200. He said that is inexpensive compared to other parts of the country.

He recently added a $5 fuel surcharge because of rising gas prices. His mobile unit only gets 5 to 6 miles a gallon, he said.

He said one downside is he doesn't have an organized retirement plan and if his mobile unit has a problem, he can be out of commission for days.

Rossi, 51, on the other hand, works mostly out of her car, hauling a suitcase of supplies and a bag with a scale into each home. She even keeps a centrifuge — which spins the blood to ready it for the lab — on her front passenger car floor.

A lab picks up the blood for tests at her house twice a day and she does other routine lab work in her basement.

She charges $55 for an exam, vaccination and travel. She mostly sees dogs and cats within 50 miles of her Fox Point, Wis., home, but works out of a clinic on Fridays for surgeries, which average $150 to $450.

Rossi worked for a clinic for 13 years before deciding to become self-employed as a house-call veterinarian five years ago.

She now earns more than ever and her business has grown about 15 percent each year, Rossi said.

"Most of the time I didn't really need the facilities of the clinic," she said. "It was mostly me using my skill with people to solve the problems."

Rossi, whose business has come from word of mouth, said meeting pets in their environment also helps her recommend treatment. She said she once saw an arthritic older dog that slipped on wooden floors. She recommended the owner get sturdy rugs to help the dog get around, which likely wouldn't have been considered if the pet had visited a clinic.

Rossi said she has done some cat neuters at homes and many euthanasias. She said she takes the euthanized animals to a pet cemetery.

She said a downside to the job is getting blood from cats. She has taught people how to hold a cat so it doesn't get away, but if she or the person gets hurt, she just "aborts the mission," she said.

"For the most part, they are much better at home," Rossi said.