The blood-pressure reading was fine, and now the veterinary anaesthestist picked up a small electric clipper to clear a patch of fur from my dog's foreleg, just above the paw. This was too much. Stoic through even the tightening of the blood-pressure cuff, he now began to quaver in a way I'd never seen.

"He's probably just picking up on your anxiety," the vet tech said. I nodded and tried harder to act like a $1400 (about R10 000) veterinary brain scan under general anaesthesia was no big deal.

But the dog knew better, and so did I. Looking down at my companion for more than half of my adult life, I thought, I hope this is the right thing.

Bear was a mutt who looked a lot like a black Lab, until you stood him next to one. He was 14, and he'd survived falls through pond ice, fracas with raccoons, tangles with barbed wire, transatlantic air travel and even a bounce off the bumper of a moving car. Nothing fazed him, except thunder and, oddly, brooms. It was part of his charm.

But now Bear was sluggish. He had loss of sensation in his paws, and was running mysterious fevers. And he wasn't getting better. The vet diagnosed a thyroid condition, but beyond that, he was stumped. He sent us to a veterinary neurologist, who, suspecting a brain tumour, had sent us here, to the IAMS Pet Imaging Center in Virginia in the US.

Pet medicine
"An MRI [magnetic resonance imaging] for a dog?" said an acquaintance. "You're kidding, right?"

I was having trouble wrapping my brain around the idea myself. I'd always been a fan of the approach enshrined in James Herriot's All Creatures Great and Small, where the vet is kindly and competent and does things the old-fashioned way.

And now we were in the middle of an expensive brain scan. And if there was a tumour? How would I know how much treatment was right and how much was too much? And how much could I afford? Already we were flying on credit cards; I'd just refinanced my house to pay off debt, and now the numbers were rising again.

The waiting room was full of other people seeking similarly sophisticated treatments. We were all locked inside our own compartments of worry. Far be it for me to make waves by asking whether anyone else was as surprised by these prices as I was. At leading veterinary teaching hospitals in the US, surgeons now routinely perform procedures that once were reserved just for racehorses and champion purebred dogs: kidney transplants, chemotherapy, hip-joint replacements.

"Pet owners began to ask, 'If medical science can remove my cataracts, why can't it take out my dog's'?" says Jack Walther, past president of the American Veterinary Medical Association. "And the answer was, we could. We'd just never been asked." Now many people think of their animals as members of the family. Pets are living longer, too. From 1987 to 2000, the life spans of the average dog and cat increased by more than one-third, thanks to better food and widespread vaccination. But longer life means a jump in the diseases of old age – cancer, organ failure, arthritis. With the family pet now ensconced on the bed instead of in the garden, medical problems are easier to spot and harder to ignore.

Woman's best friend
I heard him before I met him. He was barking continuously, deep yelps with a clear undertone of panic. An investigation behind the chicken coop of a farm near where I was visiting in Frederick, Maryland, revealed a small dog, emaciated and tethered to the ground with a rusted chain. He appeared to be about a year old. He had a short black coat, a head sleek as a seal's, lively brown eyes and floppy ears.

He was being detained for the crime of chasing sheep, a serious offence in farm country, and was on his way to the pound. He was in trouble, and he seemed to know it.
"Believe me, you don't want that dog," said the farmer.
But I did, and two days later, I had him.
"Good luck," the man said. "You're gonna need it."
As it turned out, that dog was my luck instead. Over the next 13 years, he was a guide into worlds I never would have discovered on my own. We walked in the mornings, in the evenings and late at night. We saw rabbit holes, deer tracks, raccoons and foxes, and heard the unsettling scream of owls long after dark.

He was everything to me. But a dog, as any reasonably sane dog lover knows, is not a child, a substitute spouse, a burglar alarm, status symbol, psychotherapist or even a friend, not in the human sense anyway. A dog is a dog, which turns out to be more than enough.

By the age of ten, what a friend described as Bear's "rambunctious good cheer" had mellowed. He feinted lunges at squirrels instead of giving actual chase. By 12, he was having serious trouble on stairs, and his face was white around the eyes and muzzle, giving him the look of a wise raccoon.

I met each small loss with fierce resistance. Trouble on the verandah steps? My boyfriend built a ramp. Paws slipping on the bare floor? Rugs were laid. Need a boost up the staircase each night? I boosted away.

But the day came when what had seemed mere old age began to look more like disease. Bear was stumbling regularly, his reflexes were slower, and some days he hopped across the garden as if it were covered in hot coals.

The brain scan was negative. But in early March, Bear began to run a high fever and suddenly could not take more than a few steps without help. The vet made an emergency house call. He thought Bear's spleen looked distended. Have an internist check it with ultrasound, he said.

The spleen was fine, but the test revealed something much worse.

Operate or inject?
"Bingo," the internist said, returning with a syringe of dark, plum-coloured fluid pulled from Bear's gut. There was a hole in Bear's intestine, and a massive abdominal infection. There were two options: operate immediately, or, the doctor said, "I'm afraid we have to put him down."

I looked at Bear. He was clearly in pain, but he was alert. It did not seem possible to give up on him. I stroked his head and gave the go-ahead.

If Bear survived the operation, he would need at least two days in intensive care, followed by massive doses of antibiotics. The vet said he'd seen old dogs survive and recover very well. His own dog was one of them.

But Bear died on the operating table, before the surgeon could save him. He was weak from infection, and his heart did not tolerate the anaesthesia, the vet said.

The emergency room vet cried and said how sorry she was. There was no sign of cancer, and we'd never know what caused the intestinal hole.

He will be missed
They brought me Bear's collar and tags, and said they could make a cast of his paw print if I wanted. I asked if I could see him. A nurse led me into a small examining room, where they'd laid him on a pretty pink-and-white striped sheet. His upside ear was cocked, as if he were listening.

In the foyer, they handed me the paw print. I didn't want to go home. I went to a club near my house and listened to a country band, waiting. When my boyfriend arrived, we went to my house and walked out to the garden. It was strange to think we'd never see Bear nosing around in the grass again. The squirrels would be happy he was gone. They'd noticed immediately when he'd begun slowing down, and soon were walking, not running, to the nearest tree when they saw him gingerly step down the back-verandah ramp.

There was a full moon that night. In the sky, a dozen birds moved across the face of the moon in a bright white V. They may have been geese heading north for the summer. Or possibly they were cranes, which also migrate at that time of year. White cranes are a sign of luck in many parts of the world. So, in my head, I made them cranes and hoped they would bring Bear luck, wherever he was.

A few days later, a vase of flowers arrived on the front doorstep. There was a card. It was from my veterinary clinic. "With sympathy for the loss of Bear," it said. "He will be missed."