Oh, the things you do for love! For some pet owners, the sky's the limit when it comes to keeping their animals happy and healthy. Sure, it's easy to spoil little Fifi or Tinkerbell with an $800 engraved cardigan, motion-activated litter box or hypoallergenic dog bed with built-in Shiatsu massager. But what about critters that require a serious commitment of TLC: time, love and cash?

But I adore my animals, you argue. I'd do anything to keep them alive and kicking. You've dislodged hairballs with your fingers, force-fed your pooch pills, administered ear drops and massaged foul-smelling ointments into places you'd rather not mention. Maybe you've even gone a step further, dropping a cool grand or two to surgically remove a tumor or clear a chunk of old tennis ball from a bowel.

But how far are you willing to go? Would you custom-order a puppy prosthesis from Europe? Give your kitty expensive IV drugs once a month? Cancel a trip to Cancun because your absence would literally stress your dog into a coma? When it comes to caring for furry friends, commitment can be a slippery slope.

What Marilyn and Leonard Richer of Essex Junction do for their cat, Bunnie, would hardly be considered heroic measures. Bunnie is a 12-year-old Manx who came down with adult-onset diabetes a year and a half ago. Like many fluffy felines her age, Bunnie began showing the classic signs of diabetes: weight gain, excessive thirst and high urine output.

So the Richers called Dr. Gary Sturgis, an Essex vet, who diagnosed the disease and prescribed twice-daily insulin injections, which Marilyn administers herself. "It took us quite a while to get her insulin set to find out how much she should be taking," says Marilyn. "They don't hurt her, unless you go deeper under the hide than you're supposed to."

Sturgis also comes out to the Richers' house every three months to draw Bunnie's blood and check her blood sugar throughout the day to make sure she's getting the right insulin dose. "It's expensive when the vet comes three or four times a day," Marilyn admits. "I tried to convince Dr. Sturgis I could take her blood, too. I'd given allergy shots to my son before. I had three boys, so that makes me part nurse."

Aside from feeding Bunnie a special diet -- many pet-food companies now make food specially formulated for diabetic animals -- caring for a diabetic cat is pretty routine. But what about a paraplegic dog?

Mona is a 10-year-old black-lab mix who cruises around on two legs and two wheels. Mona, who lives with Lauren Gammon and Bobby Stoddard in North Ferrisburgh, ran off from their house along Route 7 about two years ago. Mona was gone for three days before Gammon and Stoddard got a phone call from someone who'd found her lying in a ditch several miles down the road, in shock and covered in blood. Apparently, she had been hit by a truck and left for dead.

Mona was rushed to a nearby animal hospital. There, a veterinary surgeon from Brattleboro installed several metal rods and screws into her spinal column -- her spine had been knocked almost an inch out of whack. Three thousand dollars later, Mona's life was saved, but she'd lost use of her hindquarters.

Stoddard special-ordered a cart from England so Mona could get around. It took the dog some time to adapt to her new wheelbarrow-like prosthesis. Even the slightest incline would stop her dead in her tracks. "But now she cruises on the street like nobody's business," Gammon says. "She'll go over anything. She's gone off cliffs and down stairs. And she's figured out her turning radius."

Mona is also an agile swimmer. Gammon and Stoddard pop her out of her cart, dump her in the water and away she goes. Mona has adapted so well to her disability that she was once featured on an episode of the TV show, "Clifford, the Big Red Dog." Since she doesn't do well in the ice and snow -- Mona's owners have balked at the suggestion that they put her cart on skis in the winter -- Mona spends winters in a first-floor Manhattan apartment.

Mona has other special needs as well. A couple of hours after she eats, Gammon or Stoddard has to take her outside to "transact her business" for her. "You can feel when her bladder is full," Gammon explains. "You start from the top and push your way down and out comes the pee." Same story with number two. They place Mona in a squatting position, squeeze her like a tube of toothpaste and... you get the idea.

You might think you could handle a Bunnie or a Mona. A few hypodermic needles, a can of three-in-one oil to lubricate Mona's wheels -- what's the big deal?

But what about a 165-pound Rottweiler who will literally die if he gets too stressed? Four years ago, Megan Foster of Burlington bought "Z" from a Vermont breeder. "I know they're not breeding anymore because they had a lot of problems with their last litter," says Foster with a cynical laugh. "And mine is the definite lemon."

Talk about an understatement. In August of 2001, Foster and her husband came home to find Z lying on the floor, unconscious and in shock. They rushed him to the doggie ER, where an astute vet recognized his symptoms as Addison's disease, a disorder in which the adrenal glands stop producing hormones. At the time, the vet gave Z a 50-50 chance of survival. The Fosters, who had just gotten married a month earlier, were scheduled to go on vacation in Mexico.

They immediately canceled their trip and transferred Z to the River Cove Animal Hospital in Williston. He spent the next week hooked up to an IV. His weight dropped to 80 pounds. When Z was finally released from the hospital, he was put on a daily dose of steroids, which he has to take for the rest of his life. In addition, every 25 days he gets an injection of Percorten, a drug Foster calls "liquid gold," since it costs her $200 a pop. Z also receives regular blood work-ups three times a year to ensure his medications are working properly. Currently, Z's drug bills alone run about $2500 a year.

Since Z's body cannot produce certain hormones, any spike in his stress levels can be lethal. "We keep a very stress-free environment," Foster explains. That's not as simple as it sounds, since the Fosters' bull-terrier mix, Zola, has epilepsy. They control her seizures with regular doses of Phenobarbital. The Foster's third dog, a miniature pinscher named Zelda, has no physical problems. But Foster says he suffers from "big-dog syndrome." In other words, he's an obsessive yapper who requires a bark collar to keep the neighbors mollified and the police at bay.

Obviously, the Rottweiler cannot be boarded -- separation anxiety is too stressful for him. As a result, Foster and her husband haven't taken a vacation together since their honeymoon two years ago. "I've probably got six unused airline tickets," Foster confides with a laugh.

The rotten Rotty woes don't end there. In Z's short life, he's also been treated for mange and had three hip replacements -- no small accomplishment for an animal with only two hips. "The Rottweiler is like the million-dollar dog," says Foster. That's only a slight exaggeration. In four years Foster estimates she's spent at least $40,000 on Z's medical care. While pet insurance covered a small fraction of those costs, it's since been canceled and Foster has covered most of the dog's medical expenses with credit cards. She even took a second, part-time job just to cover Z's bills.

Adding insult to injury, the steroids make Z excessively thirsty, so he drinks close to 10 gallons of water a day. Because all those drugs are hard on his kidneys, Z needs a doggy door so he can relieve himself at frequent intervals. In the winter the Fosters' heating bills go through the roof. "It's just one thing after another," she laments.

Most pet owners would have thrown up their hands $38,000 ago. But not Foster. "My friends and family thought I was crazy when I was going through all his hip stuff," she says. "But to me, once you get an animal, it's a lifelong commitment and you follow it through."

And what about her spouse? Foster admits he's a bit frustrated that their lives revolve around their dogs. But his wife points out the dogs came before the husband. So he sticks by her.

Now that's love.